What Size Standby Generator Do I Need for My Austin Home?

Why Austin Homeowners Are Installing Standby Generators

February 2021 changed the conversation about backup power in Texas. Winter Storm Uri pushed the ERCOT grid to the edge of a complete collapse, leaving millions of Texas households without power for days — in freezing temperatures. Pipes burst. People were hurt. The event was a reminder that grid reliability in Texas is structurally different from the rest of the continental U.S., and that outage scenarios that seemed remote are very real.

But Uri wasn't the only data point. Summer heat in Austin routinely pushes ERCOT into conservation watches and emergency alerts. Severe thunderstorms cause localized outages that can last hours or days in the affected neighborhoods. For households with medical equipment, young children, elderly residents, or simply the expectation that home systems should keep running when the grid doesn't, a standby generator is a practical response to a documented risk.

Unlike portable generators, which require manual setup, fuel management, and outdoor placement with extension cords, a standby generator is permanently installed, connected to your home's natural gas or propane supply, and starts automatically within seconds of an outage. You don't have to do anything. The transfer switch isolates your home from the grid, the generator starts, and your selected circuits restore power. When utility power returns, the process reverses automatically.

How Generator Sizing Works

Generator output is measured in kilowatts (kW). The question of what size you need comes down to how many kilowatts your home requires to run the loads you want to keep powered during an outage — and critically, what those loads require when they first start up, not just when they're running steadily.

Running Watts vs. Starting Watts

Every motor-driven appliance — air conditioners, refrigerators, well pumps, sump pumps — requires more power to start than to run. An air conditioner that draws 2,000 watts while running may require 5,000 to 6,000 watts at startup. A generator must have enough capacity to handle these startup surges without shutting down or causing voltage instability.

This is why undersized generators fail in real use: the numbers look fine on paper when you add up running watts, but the first time the AC cycles on, the generator trips offline. Proper sizing accounts for the largest motor load startup surge, not just the steady-state totals.

Essential Circuits vs. Whole-Home Coverage

The first question to answer is what you actually want to power during an outage. The options generally fall into two categories:

• Essential circuit coverage: HVAC, refrigerator, select lighting, outlets in key rooms, possibly a sump pump or well pump. This approach prioritizes the systems needed for habitability and safety without powering the whole home.
• Whole-home coverage: All circuits in the home, including high-draw appliances like electric ranges, electric dryers, and EV chargers. Whole-home coverage typically requires a larger generator and may involve load management to prevent overloading during peak use.

Most Austin households land somewhere between these: they want HVAC, the refrigerator, a few circuits in the kitchen, key lighting, and possibly a home office or medical equipment circuit. This is well within the capability of a properly sized generator without requiring whole-home coverage.

Generator Size Guide for Austin Homes

10–14 kW: Essential Circuit Coverage

A 10 to 14 kW standby generator is appropriate for a moderately sized home where the goal is essential circuit coverage — HVAC (single system), refrigerator, kitchen outlets, lighting, and a few additional circuits. This range handles a typical Austin home's critical loads without covering high-draw appliances like an electric range or electric dryer simultaneously.

This size is commonly installed in 1,500 to 2,500 square foot homes where the HVAC system is a standard residential unit (3 to 4 ton). If you have a heat pump rather than a gas furnace, the electrical draw is higher than a gas system, which pushes toward the upper end of this range or into the next tier.

18–22 kW: Most Austin Homes

The 18 to 22 kW range covers the majority of Austin residential installations. At this size, a generator handles whole-home coverage for typical loads — both HVAC systems in a larger home, the full kitchen circuit load, lighting throughout the house, office equipment, and most appliances. Electric ranges and electric dryers can typically be run individually, though running them simultaneously alongside HVAC requires attention to load management.

This is the sweet spot for Austin homes in the 2,000 to 4,000 square foot range with standard to moderately upgraded electrical systems. It provides meaningful whole-home coverage without the cost and infrastructure requirements of the largest units.

26 kW and Above: Larger Homes and High-Draw Loads

Homes over 4,000 square feet, homes with multiple HVAC systems (particularly multi-zone systems or separate AC units for a detached studio or guest house), pools, or households that want unrestricted use of high-draw appliances during outages will benefit from a 26 kW or larger unit.

At this tier, generator systems often incorporate automatic load management modules that prioritize circuits intelligently — ensuring the generator never exceeds its rated output even if multiple large loads attempt to run simultaneously.

Natural Gas vs. Propane in Austin

Austin Energy's service territory has extensive natural gas infrastructure, and most homes in established neighborhoods have natural gas service. For these homes, a natural gas standby generator is the most convenient option — the fuel supply is continuous from the utility, there's no tank to fill, and natural gas service was uninterrupted even during Winter Storm Uri in most areas (though some localized outages did occur).

For homes in newer outer-ring neighborhoods, acreage properties, or areas without natural gas service, propane is the standard alternative. Propane generators perform identically to natural gas units but require an appropriately sized propane tank — typically 250 to 500 gallons for whole-home backup use. The tank must be sized to provide adequate runtime, and propane levels need to be monitored between outage events.

Your electrician and your gas contractor will coordinate on the fuel supply side of the installation. In Austin, natural gas connections for generators require coordination with Atmos Energy or Texas Gas Service depending on your location, and the gas line work must meet local code requirements including proper sizing for the generator's BTU demand.

What the Installation Process Involves

A standby generator installation is a multi-trade project that involves electrical work, gas work, and in most cases a concrete pad. Here's what the process looks like end to end.

Site Selection and Pad Installation

Standby generators must be located a minimum distance from windows, doors, and gas meters per manufacturer specifications and local code — typically at least 18 inches from openings and 5 feet from gas meters, though requirements vary by jurisdiction. The unit sits on a poured concrete pad or a pre-cast composite pad, installed level on compacted ground.

Most Austin homeowners place the generator along a side or rear exterior wall, within reasonable distance of both the main electrical panel and the gas meter. Your electrician will assess the site and advise on the optimal placement.

Transfer Switch

The transfer switch is the electrical component that isolates your home from the utility grid when the generator is running, preventing backfeed onto utility lines — which is both a safety issue and a code requirement. Standby generators use an automatic transfer switch (ATS), which monitors grid voltage and initiates the transfer sequence automatically when an outage is detected.

Transfer switches come in two main configurations: a whole-home ATS that transfers the entire main panel, or a load center ATS that manages a sub-panel of selected essential circuits. The right configuration depends on whether you're targeting essential circuit coverage or whole-home coverage, and what your generator's output capacity supports.

Electrical and Gas Connections

The electrical connection runs from the transfer switch to the generator, and the gas connection is made by a licensed plumber or gas fitter from the existing gas supply line. Both connections require permits and inspection in the City of Austin.

Permit and Inspection

Generator installations in Austin require permits from the City of Austin Development Services Department for both electrical and mechanical (gas) work. The inspection process ensures the installation meets code and is documented — which matters for homeowner's insurance coverage and for any future sale of the property. A properly permitted and inspected installation is also your protection if something goes wrong: unpermitted generator work has voided insurance claims in documented cases.

Commissioning and Testing

After installation and inspection, the generator is commissioned: the system is tested under load, the automatic transfer function is verified, and the weekly self-test timer is programmed. Standby generators run a brief self-test cycle weekly to confirm they'll start when needed. Your electrician will walk you through the controls and what to expect during an actual outage.