Hill Country Backup Power Guide: Generators, Solar Batteries, and Grid-Tie Realities

This guide provides general information about backup power systems in the Texas Hill Country. It does not constitute engineering, electrical, plumbing, legal, or financial advice. Consult with licensed professionals for system design, installation, and compliance with local codes and utility requirements. Bill Ross is a licensed Texas real estate agent, not an electrical engineer, licensed electrician, or energy consultant.

Why Every Hill Country Homeowner Needs a Backup Power Plan

Picture this: A hard freeze shuts down the regional grid. Roads iced over delay repair crews. Your well pump needs electricity. Your septic aerobic system needs electricity. Your propane furnace needs electricity to light and circulate. Your refrigerator is defrosting. Your phones are dying. And the forecast says the cold will last another 48 hours.

Now picture a summer scenario: A thunderstorm knocks out power to your subdivision. The HVAC compressor on your neighbor's roof is silent. Your well pump has stopped. The ice cream in the freezer is melting. And with temperatures in the upper 90s, your home will become uncomfortable within hours.

These are not hypothetical scenarios in the Hill Country. They happen regularly enough that having a backup power plan is not paranoia. It is basic homeownership.

This guide walks you through the real options: generators, batteries, solar, and hybrid systems. It gives you the numbers to compare them, the worksheets to size them, and the checklists to make sure you are not buying a system that cannot actually start your well pump or run your HVAC when you need it most.

The 30-Second Answer

Before we dive deep, here is the quick comparison you came for:

Pricing basis and date: Verified as of August 23, 2026. All figures are cash prices before any incentives. Rows labeled “equipment only” exclude every home-connection cost; standby, battery, and solar figures are turnkey installed ranges for a critical-loads (partial-home) transfer scope unless a whole-service scope is specifically quoted. Inclusions and exclusions vary by project — see the line-item breakdowns in Section 5. Where the evidence does not support a narrow range, treat the figure as a planning allowance — not a quote.

A code-compliant connection to household wiring can add the cost of an inlet, transfer switch or approved interlock, breakers, wiring, permits, and electrician labor. A portable generator used only with individual extension cords does not have those home-connection costs but must never be connected to house wiring through a receptacle.

Costs are approximate installed price ranges for 2026. Real-world quotes in the Hill Country vary significantly based on site-specific factors. Turnkey pricing typically includes the core equipment, an automatic or manual transfer switch, standard electrical labor, and utility commissioning. Project costs may also include a pad or mounting system, trenching, transfer or isolation equipment, service upgrades, permits, inspections, engineering, utility review, and HOA review. Which items apply depends on the equipment, site, authority having jurisdiction, utility, and recorded restrictions. Always secure a line-item, site-specific estimate from a licensed Texas contractor.

Critical Distinctions to Understand First

Before choosing any system, you need to understand a few things that are often confused:

1. "Off-grid" means no utility connection at all. Most systems discussed here are grid-connected. They provide backup power during outages but normally rely on the utility.
2. A grid-tied solar array alone does NOT keep your house powered during an outage. A standard grid-tied photovoltaic system normally shuts down during a utility outage so it cannot energize utility lines. Limited daytime backup without a battery is possible only with equipment specifically designed, listed, configured, and approved for that function. For example, Enphase's IQ8 Sunlight Backup architecture can serve selected essential loads while adequate sunlight is available; it is not equivalent to battery-backed or whole-home power. enphase.com/sunlight-backup
3. A battery stores energy; it does not create it. During a long outage, a battery must be recharged by solar, a generator, or the restored grid. A fully charged battery with no recharge source will eventually run out.
4. A generator produces electricity as long as it has fuel and is functioning. But fuel runs out, generators need maintenance, and they produce exhaust that must be safely vented.
5. "Whole-home backup" does not mean every appliance runs simultaneously. Even a large generator or battery system may require load management to avoid overloading the system during peak demand.
6. Kilowatts (kW) measure power. How much electricity equipment can deliver at one moment. Kilowatt-hours (kWh) measure energy. How much is stored or used over time. Dividing 13.5 kWh of nominal energy by an 11.5 kW output gives a theoretical nameplate duration of about 70 minutes. Real backup duration is lower or otherwise different because the battery may preserve a reserve, output may vary, usable energy can differ from nominal energy, and conversion and environmental losses apply.
7. Not every outage is an ERCOT failure. A tree falls on a neighborhood transformer. A car hits a utility pole. Ice weighs down a distribution line. Many outages can be local and short, while severe weather can also cause longer, wider disruptions.
8. Utility interconnection, permitting by the applicable authority having jurisdiction, and HOA review are distinct processes that may apply. Not every property is inside a municipality or HOA, and a non-paralleling generator is not reviewed under the same utility process as exporting solar.

Section 1 - Start With the Loads, Not the Equipment

The biggest mistake homeowners make is shopping for generators or batteries before they know what they actually need to power. The right system depends entirely on what you are trying to keep running.

Three Categories of Loads

Category A - Life-Safety and Essential Loads

These are the loads that protect health, safety, and basic habitability:

• Medical devices (oxygen concentrators, CPAP machines, powered wheelchairs)
• Refrigerated medications (insulin, biologics)
• Heating system controls and blower motor
• Refrigerator and freezer
• Well pump or municipal-water booster pump
• Septic or aerobic treatment system controls
• Communications (router, ONT, phones, charging)
• Essential lighting and a few key outlets
• Garage door or gate access

Category B - Property-Protection Loads

These protect your home and property:

• HVAC or limited heating/cooling
• Pool and spa freeze-protection equipment
• Well-house freeze protection (heat tape, enclosure heaters)
• Sump or grinder pumps
• Water-softener or treatment controls
• Livestock-water systems
• Security cameras and alarm systems

Category C - Convenience and Discretionary Loads

These improve comfort but are not essential:

• Electric ovens and ranges
• Clothes dryers
• Multiple HVAC systems at once
• EV charging
• Pool heaters and large spas
• Nonessential lighting and outlets
• Large entertainment equipment

Understanding Running Watts vs. Startup Watts

This is a critical technical concept in this guide. Obtain running current, locked-rotor or starting current, voltage, phase, and control information from the exact nameplate, manufacturer data, installer, or field measurement. A soft starter or variable-frequency drive may reduce starting demand, but the result must be verified for the specific motor and controller.

The Loads That Surprise People

Private well pumps are the number one surprise. Obtain running current, locked-rotor or starting current, voltage, phase, and control information from the exact nameplate, manufacturer data, installer, or field measurement. A soft starter or variable-frequency drive may reduce starting demand, but the result must be verified for the specific motor and controller.

HVAC Systems and Emergency Heat Strips: Electric auxiliary or emergency heat can add a large sustained load, commonly in staged banks. Determine the installed strip capacity and staging/control behavior from the exact air-handler documentation. A qualified HVAC technician and electrician should decide whether the backup design will carry, stage, automatically shed, or professionally lock out auxiliary heat. Do not instruct an owner to alter HVAC wiring or controls.

Septic and aerobic treatment systems need power for their blowers, pumps, controls, and alarms. For septic systems, record each pump, blower, alarm, and control load and its actual duty cycle; do not assume every component runs continuously.

Aerobic Septic Discharge Pumps: Aerobic septic systems may include an aerator, controls, alarms, and one or more pumps that operate on different schedules. During an outage, reduce water use and ask the system's maintenance provider to identify the actual wattage, duty cycle, pump-chamber reserve, alarm behavior, and maximum safe outage time for that permitted design. Do not promise a universal 24 to 48-hour window.

Two-Pump Well Infrastructure: A well system may include a submersible pump, storage tank, booster pump, controls, and treatment equipment. Determine whether the two pumps can actually start together or whether controls can stagger them. Size for the credible operating sequence, measured/nameplate current, voltage, pressure needs, and any approved soft-start or variable-frequency drive  not an assumed simultaneous startup.

Tankless water heaters: Do not group all tankless water heaters together. A whole-house electric tankless heater may draw tens of kilowatts while heating water; a propane or natural-gas tankless unit generally uses much less electricity for controls, ignition, and the fan. Use the exact unit's nameplate and manual.

Required Load Worksheet

Use the full printable load worksheet in Tool 1: Load Worksheet under Printable Tools and Checklists below. That tool includes the same table with blank lines for every load, the formulas, and space to record nameplate data.

Three Worked Examples

How to read these examples: every nameplate value below is an assumed, illustrative figure for typical residential equipment  it is not a measurement of any specific product. Replace each value with the nameplate, manual, or field-measured data for your own equipment before sizing anything (the blank worksheet in Printable Tools is built for exactly that). Each example then calculates four different quantities, because they answer four different questions: (a) peak coincident running kW sizes the continuous rating, (b) momentary starting kW sizes the surge/transient rating, (c) average kW drives fuel burn and battery drain, and (d) daily kWh sizes stored energy. A single "watts" number cannot do all four jobs.

Example 1: Subdivision Home, Municipal Water (gas heat; air conditioning not on backup)

Sizing against both ratings: continuous requirement 2.1 kW × 1.25 design margin ≈ 2.7 kW; transient requirement 2.9 kW. A quality inverter generator in the 3–3.5 kW class meets both if its manufacturer derating for heat, altitude, and fuel type still clears 2.7 kW  check the derating table for the exact model. A 13.5 kWh nominal battery with a 10% reserve and ~10% conversion losses has roughly 10.9 kWh usable: about 1.5 days at this profile, with both power numbers far inside a modern battery inverter's ratings (verify continuous kW and motor-starting capability on the spec sheet). Adding one 3-ton air conditioner (assumed ~3.5 kW running with a locked-rotor start several times that) changes the sizing class entirely  model it explicitly with its own nameplate before choosing equipment.

Example 2: All-Electric Home with Pool (~3,300 sq ft, two occupants working from home; hot-season model)

Sizing against both ratings: with engineered load management (heat strips locked out by the installer, pool and dryer shed) the continuous requirement is 8.3 kW × 1.25 ≈ 10.3 kW and the transient requirement is 13.3 kW  an 11–14 kW standby class after derating checks, contingent on the soft starter being verified on the actual compressor. With no load management at all, the 19.8 kW running load plus starting surge is what pushes homes like this into the 22 kW-and-up class that whole-home quotes reflect. A single 13.5 kWh battery (~10.9 kWh usable) covers about 4 hours at the 2.7 kW hot-season average  it cannot carry this home through a summer day alone, and the heat strips must stay shed: a 10 kW strip stage would exceed many single-battery continuous ratings and would drain the usable energy in about an hour.

Example 3: Rural Home with Well and Livestock (propane heat; cold-season model)

Sizing against both ratings: the continuous requirement is modest (2.9 kW × 1.25 ≈ 3.6 kW) but the 7.9 kW well-pump start dominates  this profile is sized by its transient, not its running load. That means either a generator whose surge rating clears 7.9 kW (typically the 6.5–8 kW conventional class), or a smaller unit paired with a soft starter or VFD whose performance is verified on this exact pump. A 13.5 kWh battery (~10.9 kWh usable) covers about 16 hours at the cold-season average, provided the battery inverter’s motor-starting rating clears the well pump’s verified starting demand.

Twenty-four-hour fuel requirement for any generator option: calculate it from the exact proposed model’s manufacturer fuel-consumption table at the expected load. Multiply gallons per hour by expected operating hours, then confirm usable tank capacity, required fuel pressure, cold-weather performance, and the refill plan with the installer and fuel supplier. As one model-specific illustration, Generac lists approximately 2.53 gallons of LP per hour at 50% load for a particular 22 kW model [15]; 24 hours at that rate would be about 60.7 gallons. Generac 22 kW Specifications [15]

Section 2 - Generator Options and Fuel Realities

Portable Generators: The Baseline

A portable inverter generator ($500-$2,500, equipment only) is the cheapest entry point. It is quiet, fuel-efficient, and suitable for short outages if you can manage which loads it serves. A portable generator needs approved transfer or interlock equipment only when it is connected to the home's wiring. Individual appliances may instead be supplied directly with properly rated cords, following the generator manual and all carbon-monoxide precautions. Never backfeed through a wall outlet.

A portable conventional generator ($800-$3,000) offers more power at lower cost but is louder, less fuel-efficient, and produces more exhaust. It is a reasonable backup for occasional use if properly maintained and operated.

A listed transfer switch or properly selected panel interlock [9] is required when a portable generator is connected to the home's wiring system. A homeowner powering individual appliances directly with correctly rated outdoor extension cords does not connect the generator to the house panel, but must still follow the generator manual, cord ampacity and length limits, GFCI/grounding instructions, weather-protection rules, and carbon-monoxide precautions [8]. Never backfeed through a dryer receptacle, wall outlet, or homemade cord.

Permanently Installed Standby Generators

A standby generator is permanently installed outside your home, connected to your electrical panel through an automatic transfer switch (ATS). When power goes out, the transfer switch signals the generator and it starts automatically. The startup time depends on the specific ATS and generator controller configuration.

Propane vs. Diesel: Specifications to Request From Your Installer

Rather than presenting universal facts that vary by model, installer, and site, the table below identifies exactly what specifications to request from any propane or diesel standby proposal. A meaningful comparison requires the specific numbers for the proposed equipment on your site, not generic claims.

Natural Gas Option

Natural gas avoids on-site refueling only while the utility maintains service and the generator receives the required pressure and volume. Runtime is still constrained by generator duty, service intervals, load, and the resilience of the gas-delivery system. Verify availability, meter/regulator capacity, and generator load by exact address with the gas utility.

Placement Rules

Generator placement must account for:

• Manufacturer clearances from windows, doors, soffit vents, and HVAC intakes
• Property lines, easements, openings, intakes, combustible construction, fuel equipment, and service access: verify the exact proposed model's listed installation instructions and every applicable local/utility/HOA requirement. Do not use a generic setback copied from another model or city.
• Noise impact on bedrooms and neighbors
• Exhaust direction (away from windows and living spaces)
• Fuel-tank access and delivery routes
• Drainage and flood-prone areas
• Wildfire defensible space (keep vegetation cleared around the unit)
• HOA architectural-review requirements: submit for architectural review if the governing documents require it. Obtain the recorded declaration, all amendments, current architectural guidelines, application form, fee schedule, submission deadline, and written decision. Do not rely only on a management-company phone call. See Texas Property Code Chapter 202 for relevant limitations on HOA authority.

Placement dimensions must be taken from the exact model's listed installation instructions and every applicable local code, utility, easement, and HOA requirement. Do not use a generic setback copied from another model or city.

Section 3 - Battery Storage and Solar

What a Battery Can and Cannot Do

When installed as part of a listed backup system with the required system controller, isolation equipment, protected-loads panel or approved whole-home configuration, a home battery (like a Tesla Powerwall 3 at 13.5 kWh or three Enphase IQ 5P units at 15 kWh total) can provide automatic and quiet backup. A battery installation does not provide outage power merely because a battery is present. It can keep essential loads running for several hours to a day or more, depending on how much you draw. But it has limits:

• Finite runtime. Runtime is estimated by dividing the energy available for the outage by the home's average outage load. A 13.5 kWh battery has a theoretical ceiling of 4.5 hours at a constant 3 kW load or 9 hours at a constant 1.5 kW load. Actual runtime will be lower when a backup reserve is retained and after system losses, temperature effects, and degradation are considered. For example, a 10% reserve alone reduces those ceilings to about 4.05 and 8.1 hours before other effects. Cycling appliances make an hourly load profile more useful than a single peak-watt number.
• Startup limitations. Compare continuous output, short-duration surge output, voltage, and motor-starting performance separately. A battery inverter may respond very quickly but is limited by its inverter rating and stored energy. A 24 kW-class generator has a higher nameplate power rating than an 11.5 kW battery configuration, but its actual motor-starting performance, fuel rating, voltage dip, and allowable load steps remain model-specific.
• Round-trip losses, chemistry, and degradation. Battery specifications are product- and configuration-specific. Compare nominal or usable energy, continuous and short-duration output, AC or DC round-trip efficiency measured on the same basis, operating-temperature derating, expansion limits, and warranty terms. For reference, Tesla publishes 89% solar-to-battery-to-home/grid round-trip efficiency for the applicable Powerwall 3 configuration [13], while Enphase publishes approximately 90% AC round-trip efficiency for the IQ Battery 5P [14]. Warranty duration, cycle limits, retained-capacity guarantees, internet-connectivity requirements, and permitted operating modes differ. Quote the current warranty document for the exact SKU; do not turn a warranty minimum into a prediction of real-world performance.
• Low-state-of-charge recovery. Low-state-of-charge recovery is product- and configuration-specific. A battery-management system normally stops serving loads before the cells are physically depleted, but the restart behavior varies. Tesla states that a Powerwall below 10% enters standby and, when paired with solar, attempts to recharge periodically during specified daytime hours; if solar is insufficient, the system may need the grid to return. Other systems use different reserve thresholds, solar-start or black-start procedures, and manual-recovery rules. Before purchase, require the installer to document the exact low-charge shutdown threshold, protected reserve, solar-restart behavior, manual-restart procedure, communications dependency, and recovery procedure for the proposed equipment [15].

Battery-Only vs. Solar-Plus-Battery vs. Generator-Battery Hybrid

Solar Production in the Hill Country

Solar production in the Hill Country varies significantly by site conditions. A detailed, site-specific PVWatts model (NREL's PVWatts Calculator) with all inputs disclosed  location, weather file, DC nameplate, module type, system losses, tilt, azimuth, DC-to-AC ratio, inverter efficiency, and monthly AC kWh  is required before any production claim can be made.

However, solar production drops significantly in winter (2.5 to 3.5 peak sun-hours per day) and during extended cloudy periods. A solar-plus-battery system may fail to keep up during a multi-day winter outage if daily solar production is lower than daily backed-up consumption. Adequately oversized arrays, larger storage, aggressive load management, or another charging source can change the result. This is why generators remain relevant even for homes with solar and batteries.

When Solar + Battery Makes Sense

• You want to reduce your electric bill AND have backup power
• Your site has suitable orientation, tilt, shading, roof area, ground-mount options, or east/west layouts that work for your production needs; have a site-specific model done
• You plan to stay in the home for 10+ years
• You want silent, automatic backup for short-to-medium outages
• You are comfortable with the higher upfront investment

When Solar + Battery Does NOT Make Sense (Alone)

• You need to power heavy loads like heat strips or well pumps during extended outages
• Your roof faces north or is heavily shaded
• You need reliable multi-day runtime (requires a generator or extended solar recharging)
• Your budget cannot absorb the upfront cost
• You plan to sell within five years and have a financed or leased system  compare payoff balance, transfer terms, appraisal treatment, remaining warranty, electricity savings, and likely ownership period. An owned system generally does not complicate a sale the way a lease or PPA can.

Section 4 - Permits, HOAs, and Grid-Tie Rules

Approvals and coordination that may apply

Utility interconnection or service review. A solar array, battery, generator, or hybrid system that can operate in parallel with the utility grid must follow the serving utility's interconnection rules and must not be energized before any required permission to operate. A non-paralleling standby generator isolated by listed transfer equipment is different from an export-capable distributed-energy system, but some utilities  including CPS Energy  still have a backup-generator application or service-review process. Service-side transfer equipment, meter changes, gas capacity, and utility-owned equipment can also require coordination. Check the actual utility for the service address; do not infer the utility from the county or mailing city.

Government permits and inspections. Ask the city or county authority having jurisdiction which electrical, building, structural, fire, plumbing/fuel-gas, floodplain, or development approvals apply to the specific site and system. Some unincorporated properties do not have the same general permitting process as properties inside a municipality, but state electrical licensing, adopted safety codes, utility rules, easements, deed restrictions, and fuel/fire requirements still apply.

HOA or architectural review. Submit an application before installation only if the recorded declaration or architectural rules require it. Texas law limits certain HOA restrictions on standby generators and solar devices, but it does not eliminate every reasonable placement, screening, safety, or application requirement. Obtain the current recorded documents and written approval or a documented determination that approval is not required.

Texas Property Code Section 202.019 [6] limits an HOA's ability to prohibit a permanently installed standby generator, but the HOA can impose reasonable placement, screening, and operating requirements if those are documented in its recorded restrictions. This protection applies to generators rated at least 7 kW that are enclosed in a manufacturer-supplied sound-attenuating enclosure and connected through a transfer switch; smaller portable units are not covered by this statute and remain fully subject to HOA rules. Texas Property Code Section 202.010 [6] limits an HOA's ability to prohibit solar-energy devices, but certain restrictions and approval procedures remain permissible. Consult the current Texas Property Code Chapter 202 for the applicable limitations. Obtain the recorded declaration, all amendments, current architectural guidelines, application form, fee schedule, submission deadline, and written decision. Do not rely only on a management-company phone call.

Texas SB 1252 [2] took effect September 1, 2025. It prohibits a municipality from adopting or enforcing a local NEC amendment or another municipal measure regulating installation or inspection of a qualifying residential energy backup system. The statutory definition covers a residential backup system capable of providing no more than 50 kW to the residence or having no more than 100 kWh of storage. The law does not remove National Electrical Code compliance [9] or Texas electrical-licensing requirements [5], and it expressly preserves the authority of a municipally owned utility to regulate installation or inspection within that utility's service area. Do not describe this law as a blanket elimination of permits, county authority, utility review, fire/fuel rules, or HOA procedures. Confirm the facts with the authority having jurisdiction and serving utility.

Texas SB 1202 [3], effective September 1, 2025, provides a third-party pathway for reviews and inspections of one- or two-family home backup power installations connected at 600 volts or less. Depending on the task, authorized reviewers may include persons already authorized under Local Government Code Chapter 247, an electrical inspector, or a licensed master electrician meeting the statute's criteria. The reviewer or inspector must follow applicable law and deliver the required notice and records to the regulatory authority. The enrolled law says the authority must issue an applicable approval, permit, or certification by the third business day after receiving an approving notice, and construction may begin upon submission of the notice approving the development document. Utility tariffs and the interconnection/service policies of electric cooperatives and municipally owned utilities remain enforceable. Because this is a legal-process summary, verify the current statute and local implementation before relying on it.

Know Your Actual Jurisdiction and Utility

A Boerne mailing address does not necessarily mean you are in the City of Boerne or served by Boerne Utilities. The same applies to San Antonio, New Braunfels, Spring Branch, Bulverde, Fair Oaks Ranch, Bandera, and Canyon Lake addresses. Your electric bill and meter tell you which utility actually serves you.

Utility Interconnection Quick Reference

Utility requirements and links last checked August 23, 2026. Programs, forms, tariffs, fees, and contacts can change; verify the current requirements with the serving utility before contracting or installing.

Utility territories do not follow county lines. A Boerne mailing address, for example, does not prove that City of Boerne Utilities serves the property. Confirm the provider from the meter/account, utility service-area tool, seller's bill, or written utility confirmation.

Section 5 - Cost, Ownership, and 10-Year Economics

Generator Cost Breakdown

Pricing basis: Equipment-only or installed scope is noted per row. All ranges are for the equipment category and output class listed (portable generators: 5-10 kW; standby generators: 22 kW). "Typical total installed" includes the generator unit, transfer switch or interlock, standard electrical labor, pad, and permits. Excluded: site grading, trenching beyond 50 ft, service upgrades, HOA review fees, and fuel storage beyond what the installer includes. Geographic market: Texas Hill Country (Bexar, Kendall, Comal, Bandera counties). Sources: Industry pricing surveys, manufacturer MSRP data, and licensed contractor estimates (3+ sources). Pricing checked August 2026.

These are illustrative ranges, not quotes. Every property will differ based on equipment selection, site conditions, electrical service, fuel requirements, permitting, utility requirements, and contractor pricing.

Pricing basis and date: Verified as of August 23, 2026. All figures are cash prices before any incentives, for a critical-loads (partial-home) transfer scope unless a row states otherwise. A whole-service transfer, service upgrade, gas plumbing, propane tank purchase, structural work, trenching beyond the stated allowance, utility fees, engineering, commissioning, taxes, monitoring subscriptions, and first-year service are additional unless a row states otherwise. Where the evidence does not support a narrow range, treat the figure as a planning allowance — not a quote.

Battery and Solar Cost Breakdown

Pricing basis: Equipment-only or installed scope is noted per row. All ranges are for the equipment category and output class listed (battery only: 13.5 kWh; solar + battery: 10 kW DC solar + 13.5 kWh battery). "Typical total installed" includes battery modules, inverter/gateway, solar array, standard electrical labor, permits, and interconnection fees. Excluded: panel upgrades beyond 200 A, structural engineering, trenching, and HOA review fees. Geographic market: Texas Hill Country (Bexar, Kendall, Comal, Bandera counties). Sources: Industry pricing surveys, manufacturer MSRP data, and licensed contractor estimates (3+ sources). Pricing checked August 2026.

These are illustrative ranges, not quotes. Every property will differ based on equipment selection, site conditions, electrical service, fuel requirements, permitting, utility requirements, and contractor pricing.

Pricing basis and date: Verified as of August 23, 2026. All figures are cash prices before any incentives — no 2026 federal Section 25D credit is applied (see the tax-credit note below this table). Figures assume a critical-loads backup configuration; whole-home backup, panel upgrades beyond the listed scope, structural work, trenching, utility fees, engineering, commissioning, taxes, and monitoring subscriptions are additional unless a row states otherwise. Where the evidence does not support a narrow range, treat the figure as a planning allowance — not a quote.

Federal tax-credit status as of August 23, 2026: The federal Residential Clean Energy Credit under IRC Section 25D [1] is not available for residential clean-energy property placed in service after December 31, 2025. Do not subtract a 30% federal credit from a 2026 proposal unless a qualified tax professional confirms that a different provision applies to the homeowner's facts. Tax rules can change; verify the current IRS guidance before signing a contract.

Texas property-tax note: Texas Tax Code Section 11.27 [7] provides an exemption mechanism for the appraised-value increase attributable to qualifying solar- or wind-powered energy devices. The Texas Comptroller identifies Form 50-123 as the application [7]. Eligibility, deadlines, and the treatment of batteries or mixed systems can be fact-specific, so ask the county appraisal district and a qualified tax professional rather than assuming the entire project is exempt.

10-Year Cost-of-Ownership Framework

No honest table can tell you a backup system’s 10-year cost, because the answer depends on inputs that are specific to your property, tariff, and equipment. Instead of a table of invented totals, run this framework with your own numbers. Gather these inputs first:

A resilience system can be rational even when this framework returns a negative financial result: avoided losses, habitability, medical continuity, water access, and convenience are real benefits that the cost math does not capture. Do the math anyway — so that whatever you buy, you buy it knowing what it costs.

The Financial Payback vs. Resilience Value Distinction

A generator does not pay for itself through electric-bill savings. It is a resilience expense. You pay for the peace of mind and property protection it provides.

Before installation, ask the insurer in writing whether the generator, solar array, battery, transfer equipment, and detached fuel tank must be scheduled or disclosed; whether equipment breakdown, electrical surge, service-line, wildfire, wind/hail, flood, and spoilage losses are covered; and whether a deductible, inspection, or installation condition applies. For propane, verify whether the tank is owned or leased, who may fill it, whether a supplier contract transfers at sale, and whether the tank location and delivery route conflict with easements or future construction. Coverage and supplier terms vary  do not promise that adding backup power automatically lowers premiums.

Solar and batteries may have economic benefits through reduced electric bills, export credits, and utility incentive programs, but the payback depends on your tariff, usage pattern, financing, and equipment life. Do not assume solar will pay for itself in a specific number of years without running the numbers for your actual situation.

These examples use stated assumptions that may not match your property. A resilience system may be rational even without a positive financial return because avoided loss, habitability, medical continuity, water access, and convenience are separate benefits.

Section 6 - Decision Guide

Use this matrix to narrow your options. Ratings reflect typical residential configurations in the Texas Hill Country. Every property is different -- verify with a licensed contractor.

Section 7 - Contractor Checklist

Get at least three itemized proposals. Use this checklist to compare them:

• What load calculation was performed, and what loads are included?
• What is the continuous and surge power rating of the proposed system?
• Can it start the well pump and HVAC simultaneously?
• What is the documented fuel consumption at 25%, 50%, 75%, and full load?
• What runtime is promised, and under what assumptions?
• What cold-weather equipment is included (block heater, battery blanket, fuel treatment)?
• Who obtains permits, inspections, and utility permission?
• Is the electrical work performed by a licensed Texas electrical contractor?
• Who is the solar retailer and each salesperson involved in the transaction? Provide the applicable Texas registration details once the statutory registration requirement is in effect, and explain any claimed exemption. Texas TDLR solar retailer/salesperson registration takes effect September 1, 2026. Because this article is dated August 23, 2026, the mandate is not yet in force; verify current TDLR status at the time of contracting.
• Which licensed Texas electrical contractor will perform or supervise the electrical installation? Provide the contractor's name and license number for independent verification.
• Does the company employ design or installation personnel with a relevant NABCEP credential? If so, identify the person, credential, and role. NABCEP is a voluntary professional credential unless a particular program or contract makes it a condition; it is not a substitute for required Texas licensing or registration.
• Who provides warranty service locally, and what is the response time?
• What happens if the installer goes out of business?
• Does the warranty cover labor, travel, shipping, and replacement parts?
• Can the system operate without internet or cloud monitoring?
• Can batteries recharge from solar while the grid is down?
• Can the generator recharge the batteries?
• What maintenance is required, and what happens if maintenance lapses?
• What are the cash and financed prices, and are there dealer fees or prepayment penalties?
• Are there UCC filings, liens, leases, or transfer requirements?
• Is monitoring included, and for how long?

Section 8 - Operating and Maintenance Schedule

The controlling schedule is the current manual for the exact equipment and the installer's approved commissioning documentation. Do not substitute the generic checklist below for the manufacturer's instructions. Tasks involving energized equipment, fuel systems, transfer equipment, battery enclosures, terminals, or control wiring belong to qualified personnel unless the manufacturer expressly identifies them as owner tasks.

Pre-Season and Severe-Weather Preparations

• Ask the propane supplier to verify adequate usable fuel for the modeled load and outage duration. The supplier must follow the tank's lawful fill limit; do not describe an LPG container as filled to 100%.
• Verify battery is fully charged through the manufacturer's monitoring interface.
• Use the manufacturer-approved backup test or commissioning procedure; do not intentionally deep-discharge the system unless the manufacturer directs it.
• Test carbon-monoxide alarms and replace batteries if due.
• Charge all portable devices and battery packs.
• Store drinking water in clean, food-grade containers. Bathtub water should be treated as non-potable and reserved for toilet flushing or cleaning unless an emergency authority says otherwise.
• If on a well, fill storage containers for drinking and cooking.
• Move valuable items away from windows.
• Know where your flashlights and manual garage-door release are.

During an Outage

• If generator auto-starts and transfers, listen for normal operation.
• If an automatic generator does not start, follow only the owner-level checks in its manual; do not open energized equipment or work on fuel/electrical components. Call qualified service when the cause is not immediately identified.
• Do NOT run a portable generator indoors, in a garage, or under a covered porch.
• Maintain the CPSC 20-foot rule for portable generators only: exhaust directed away from buildings and any openings.
• Monitor battery state-of-charge and reduce loads if it drops below 20%.
• When utility power returns, follow the exact generator and transfer-equipment manuals. An automatic standby system should complete its programmed retransfer and cooldown sequence. For a portable or manually transferred system, remove loads, transfer, disconnect, cool, and refuel only in the sequence required by the equipment manuals. If the sequence is unclear, use the installer or a qualified electrician; never improvise at service equipment.

Section 9 - Buying a Home With Existing Backup Power

Treat the equipment as a system that must be documented, inspected, transferred, and tested — not merely as an appliance included with the sale.

Before the option period ends, request:

• make, model, serial number, installation date, invoices, permits, inspection approvals, utility interconnection agreement, and permission-to-operate notice, as applicable;
• installer and current service-provider information, maintenance logs, outage/event history, open fault codes, recall status, remaining manufacturer/installer warranties, and written transfer steps;
• for generators, transfer-switch model, load-management modules, fuel type, fuel-use data, service-hour meter, recent load-bank or operational test, and documentation showing who owns the propane tank;
• for solar/batteries, array and inverter size, battery count and usable capacity, backup-load diagram, current production/health reports, monitoring-account transfer, internet requirements, and expansion compatibility;
• the cash purchase contract or all financing, lease, PPA, UCC filing, lien, payoff, assumption, transfer, and roof-removal/reinstallation documents;
• HOA approval, screening obligations, survey/easement conflicts, insurance disclosures or endorsements, and any outstanding permit or utility correction notices.

Hire appropriately licensed specialists to inspect and demonstrate the system under realistic loads. A general home inspection is not a substitute for generator, electrical, fuel-gas, solar, battery, well, septic, or HVAC expertise. Put ownership transfer, lien/payoff, monitoring access, warranties, manuals, keys, and a successful pre-closing operational demonstration into the transaction checklist. Document the manufacturer monitoring account, installer access, gateway ownership, and transfer process. The seller should initiate the manufacturer's ownership transfer, and the buyer should create or reset credentials in the buyer's own name. Never exchange personal passwords. Never assume an existing solar system may be energized under a new utility account; for example, PEC publishes a specific interconnection process for a buyer moving into a home with existing distributed generation [22].

PEC source: mypec.com/moving-to-a-home-with-existing-solar-or-other-distributed-generation/ [22]

See also: Hill Country home inspection checklist, our septic systems guide, the wells and Edwards Aquifer guide, the Infrastructure & Land hub, and the Hill Country relocation planning guide.

Frequently Asked Questions

Can a solar array keep my house powered during an outage without a battery?

Ordinary grid-tied solar normally shuts down during an outage. A specifically designed and approved system can provide limited daytime power without a battery while sunlight is sufficient; Enphase IQ8 Sunlight Backup is one example. Capability is limited by instantaneous solar production and the approved protected-load configuration, and it is not nighttime or stored-energy backup. Source: energy.gov enphase.com

How long will a Tesla Powerwall 3 run my essential loads?

Runtime is estimated by dividing the energy available for the outage by the home's average outage load. A 13.5 kWh of nominal energy battery has a theoretical ceiling of 4.5 hours at a constant 3 kW load or 9 hours at a constant 1.5 kW load. That simple 13.5 / 3 calculation is a theoretical ceiling, not expected delivered runtime. Actual runtime will be lower when a backup reserve is retained and after system losses, temperature effects, and degradation are considered. For example, a 10% reserve alone reduces those ceilings to about 4.05 and 8.1 hours before other effects (see also reserve/loss qualification). Cycling appliances make an hourly load profile more useful than a single peak-watt number. Tesla Powerwall 3 Install Manual [13]

Can I add more batteries later?

Some systems can be expanded, subject to product generation/SKU compatibility, inverter and gateway limits, electrical capacity, physical space, code, warranty, and a new permit or utility application. Design for expansion before the first installation and obtain written confirmation of what can be added later.

Do I need a permit for a generator or battery in Texas?

It depends on your jurisdiction. Senate Bill 1252 [2] (effective September 1, 2025) limits municipal regulation of residential backup systems up to 50 kW or 100 kWh, but it does not eliminate National Electrical Code compliance [9], licensed electrical work [5], utility approval, fuel rules, or HOA review [6]. Check with your local building department and utility.

Will my HOA allow a generator?

Texas Property Code Section 202.019 [6] limits an HOA's ability to ban a permanently installed standby generator, but the HOA can impose reasonable placement, screening, and operating rules. Solar panels are similarly protected under Section 202.010 [6], subject to certain restrictions. Review the recorded declaration and current architectural rules. Submit an architectural request when those documents require one, and keep the written decision. Even when formal approval is not required, the installation must comply with applicable law, permits, setbacks, safety requirements, and utility rules.

What if I have a medical device that cannot tolerate any outage?

Ask the device manufacturer and clinician for input power, acceptable transfer time, battery compatibility, alarms, and required runtime. Confirm the required power quality, transfer interruption tolerance, runtime, alarm, and backup procedure with the device manufacturer and treating provider; do not infer suitability from generator or battery kW alone. Size a listed UPS for the exact device and test it according to its instructions; a whole-home generator or battery does not by itself guarantee uninterrupted life-safety support. Keep a charged portable backup if approved, register for any utility critical-care program that applies, and maintain a relocation/emergency plan. Critical-care registration does not guarantee priority restoration.

How do I know what size generator I need?

A running-watts-plus-largest-starting-watts calculation is only a screening estimate. Motors can overlap, heat strips add sustained load, fuel type may change generator output, and voltage dip can prevent equipment from starting. Have a licensed electrical contractor perform the applicable load calculation and verify the exact generator's transient response, transfer equipment, load management, and field startup of the well/HVAC loads.

Is diesel or propane better for the Hill Country?

The choice depends on storage, delivery access, cold-weather plan, noise, load profile, maintenance capability, service network, tank ownership, and exact model data. Compare each factor against your specific property rather than relying on general assumptions.

Does solar "net metering" pay the retail rate?

Not necessarily. Terminology and export compensation vary by utility, tariff, and date. Verify the actual export-credit or buyback structure with the serving utility.

Can I connect a generator through a dryer outlet?

No. Never backfeed. Use listed transfer equipment installed by a licensed electrical contractor when connecting to home wiring.

Can a generator and solar/battery system work together?

Sometimes, but only with a designed, listed, manufacturer-supported control/transfer architecture. Compatibility must be engineered rather than assumed.

Can I pre-charge a battery before a freeze?

Many systems offer reserve or storm modes, but internet, forecast triggers, utility programs, and grid-charging rules vary. Set and test the plan before the event.

Do I need a permit outside city limits?

It depends. Check the county authority having jurisdiction, utility, state licensing, fuel/fire/floodplain rules, deed restrictions, and HOA. It is not just about the mailing address.

What happens when I sell?

Cross-reference Section 9 (Buying a Home With Existing Backup Power). Discuss payoff/assumption, UCC filings, leases/PPAs, warranty and monitoring transfer, roof work, permits, and utility account/PTO requirements.

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Related Reading

• Who Do I Call? Hill Country Directory
• Hill Country Emergency Services Directory
• Weather Resilience and Property Preparedness
• Wells and Edwards Aquifer Guide
• Septic Systems in the Hill Country
• Property Insurance in the Hill Country
• Rainwater Harvesting: Designing for Drought and Caliche
• Limestone and Caliche: What It Means for Your Property
• Disposal Directory: Where the Trash Company Won't Take Things

Printable Tools and Checklists

These print-ready worksheets help you evaluate, compare, and document every aspect of your backup power project. Each tool is designed for black-and-white printing.

Tool 1: Load Worksheet

List every load you expect to power during an outage. Use nameplate ratings, owner's manual specifications, or measured values from a clamp meter. Fill in the "Daily kWh" column using the formula below the table.

Daily energy (kWh) = watts x operating hours / 1,000
First-pass battery runtime (hours) = energy available for outage (kWh) / average outage load (kW)

Verify current rules and prices. Last reviewed August 23, 2026.

Tool 2: 24/48/72-Hour Runtime Planner

Fuel Supply Contact Information

Verify current rules and prices. Last reviewed August 23, 2026.

Tool 3: Contractor Bid-Comparison Checklist

Get at least three itemized proposals. Use this table to compare them side by side.

Verify current rules and prices. Last reviewed August 23, 2026.

Tool 4: Buyer Due-Diligence Checklist

Use this checklist when evaluating a home with existing backup power equipment. Verify each item with the seller's documentation and qualified inspectors.

Verify current rules and prices. Last reviewed August 23, 2026.

Tool 5: Maintenance Log

Record every service event by date. Keep this log with the equipment owner's manuals and warranty documents.

Verify current rules and prices. Last reviewed August 23, 2026. This document is for planning purposes only; consult qualified professionals for final decisions.

Sources

1. IRS, Residential Clean Energy Credit. irs.gov Accessed August 23, 2026.
2. TDLR, SB 1252: Changes to Residential Energy Backup System Regulations. tdlr.texas.gov
3. Texas Legislature, SB 1202 Enrolled Bill. capitol.texas.gov
4. TDLR, Residential Solar Retailers. tdlr.texas.gov
5. TDLR, Electricians. tdlr.texas.gov
6. Texas Property Code Chapter 202, including Sections 202.010 and 202.019. capitol.texas.gov
7. Texas Comptroller, Property Tax Exemptions. comptroller.texas.gov
8. CPSC, Carbon Monoxide / Portable Generator Safety. cpsc.gov
9. NFPA 70, National Electrical Code. Article 702 (Optional Standby Systems), Article 690 (Solar PV), Article 705 (Interconnected Power Production), Article 706 (Energy Storage Systems), Article 710 (Stand-Alone Systems). Applicable edition determined by the adopting jurisdiction. nfpa.org
10. U.S. DOE, Solar and Resilience Basics. energy.gov
11. U.S. DOE, Solar Integration: Inverters and Grid Services Basics. energy.gov
12. NREL, PVWatts Calculator. pvwatts.nrel.gov
13. Tesla, Powerwall 3 Specifications. Exact North American configuration. energylibrary.tesla.com
14. Enphase, IQ Battery 5P Limited Warranty and Round-Trip Efficiency Data. enphase.com and enphase.com
15. Tesla, Powerwall Best Practices During Power Outages. Best practices for Powerwall operation, reserve settings, and low-state-of-charge recovery; 10% standby threshold and solar-restart behavior. generac.com
16. CPS Energy, Distributed Generation. cpsenergy.com
17. Pedernales Electric Cooperative, Interconnection Process. mypec.com
18. Bandera Electric Cooperative, Connecting to the Grid. banderaelectric.com
19. GVEC, Interconnection Agreement. gvec.org
20. New Braunfels Utilities, Solar Energy. nbutexas.com
21. City of Boerne, Electric Utility and Distributed Generation Ordinance. ci.boerne.tx.us and Distributed Generation Ordinance
22. PEC, Moving to a Home With Existing Solar/DG. mypec.com

Links and cited requirements were accessed August 23, 2026. Utility tariffs, forms, fees, incentives, laws, manufacturer documents, and contact information can change; confirm the current controlling source before purchase, permitting, or installation.

Materially reviewed August 23, 2026: federal tax-credit status, 2025 Texas statutes, 2026 TDLR solar-retailer status, utility links, product specifications, calculations, and CPSC safety guidance.

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This article provides general information about backup power systems in the Texas Hill Country. It does not constitute engineering, electrical, plumbing, legal, or financial advice. Consult with licensed professionals for system design, installation, and compliance with local codes and utility requirements. Verify all costs, incentives, utility programs, and regulatory information before making purchasing decisions. Bill Ross is a licensed Texas real estate agent, not an electrical engineer, licensed electrician, or energy consultant.