How Long Will a Generator Run During a Houston Power Outage?

Estimated read time: 6 minutes

Last updated: July 2026 By PSL Technology LLC | Authorized Generac & Briggs and Stratton Dealer | Tomball, TX

After Hurricane Beryl knocked out power to over 2.7 million Houston-area customers in 2024 — with some neighborhoods waiting more than two weeks for restoration — the question every generator owner was asking was simple: how long can this thing actually run?

The answer depends on three things: your fuel source, your home's power load, and how well the unit is maintained. Here's the real breakdown, specific to how most Houston homes are set up.

Natural Gas: The Advantage for Houston Homeowners

Most homes in the Houston metro area are connected to natural gas service — and that's a significant advantage when it comes to generator runtime.

A whole-home standby generator connected to your natural gas line can run indefinitely, as long as the gas utility maintains service and pressure. There's no tank to empty, no delivery truck to schedule, and no running out of fuel on day 5 of an extended outage.

Here's something most people don't know: during major hurricanes and storms, Houston's underground natural gas infrastructure has historically remained operational even when the electrical grid was completely down. During Hurricane Katrina, natural gas service remained active across large parts of affected areas even as the power grid was destroyed. The gas distribution system is underground and largely protected from wind and storm damage — which is exactly why standby generators on natural gas are the gold standard for Houston homes.

Practical limit on natural gas: The limiting factor isn't fuel — it's oil. Most manufacturers recommend an oil change every 150 to 200 hours of continuous operation. Running 24 hours a day, that means your first oil change is due around day 6 to 8. With proper maintenance, a natural gas generator can run for weeks or even months during a catastrophic outage.

Propane: Runtime Depends on Your Tank Size

If your home uses propane instead of natural gas (common in newer developments and rural areas outside the metro), runtime is determined by how much fuel you have stored on-site.

Here's a realistic runtime table for common generator sizes at 50% load — which is typical for a Houston home running central AC, refrigeration, lights, and basic appliances:

Generator Size	Tank Size	Estimated Runtime at 50% Load
14kW	250-gallon tank	5–7 days
14kW	500-gallon tank	10–14 days
22kW	250-gallon tank	3–4 days
22kW	500-gallon tank	5–8 days
22kW	1,000-gallon tank	10–16 days

Keep in mind these are estimates at moderate load. On a mild day with lower AC demand, your generator runs below 50% load and fuel lasts longer. On a hot Houston summer day with multiple AC units running, consumption goes up.

Critical for propane users: Top off your tank before hurricane season starts — ideally in May or early June. Propane suppliers get slammed with refill requests once a storm enters the forecast, and delivery trucks may not be able to reach your home if roads are flooded. Never let your tank drop below 30% during storm season.

What Actually Limits Your Generator's Runtime

Oil — The Real Limiting Factor

Whether you're on natural gas or propane, the practical limit on continuous runtime is oil maintenance. Most residential standby generators require:

• Oil check every 24 hours during extended continuous operation

• Full oil change every 150–200 hours of runtime (roughly days 6–8 of continuous use)

Skipping oil changes during a prolonged outage risks engine damage that can shorten the life of your generator significantly. If you're planning to run through a multi-week outage, make sure you have extra oil on hand before storm season.

Air-Cooled vs. Liquid-Cooled Engines

Most residential standby generators (10–26kW Generac and Briggs & Stratton units) use air-cooled engines. These are designed to run continuously for around 500 hours before requiring a major service interval. For context, that's about 21 days of non-stop operation.

Larger liquid-cooled generators (typically commercial or large estate applications) can run 7–10 days continuously and are better suited to extremely prolonged outages, but they're also significantly more expensive and larger.

For the vast majority of Houston homes, an air-cooled 14–22kW standby generator on natural gas is more than capable of handling even a two-week outage comfortably.

How Much Power Does Your Home Actually Use During an Outage?

This is the question most homeowners don't think to ask — and it matters for runtime estimates.

Most homes don't run at 100% of their generator's rated capacity during an outage. Typical Houston home during an extended summer outage:

Appliance	Approximate Draw
Central AC (4-ton unit)	3,500–5,000 watts
Refrigerator	150–400 watts
Lights (10 LED bulbs)	60–100 watts
TV + devices	200–400 watts
Microwave (while in use)	1,000–1,500 watts
Typical total running load	5,000–8,000 watts

A 20kW generator running a typical Houston home at 5,000–8,000 watts is operating at roughly 25–40% of its rated capacity. That means fuel consumption is well below the "full load" figures you might see on spec sheets — and your runtime is correspondingly longer.

After the Outage: What to Do With Your Generator

Once power is restored, don't just shut your generator off and forget about it:

• Check and change the oil if you ran continuously for more than 100 hours

• Run a test cycle after the unit cools down to confirm it's ready for the next event

• Schedule a post-storm service if you noticed any performance issues during the outage — unusual noise, voltage fluctuations, or automatic shutdowns

  
  

Bottom Line for Houston Homeowners

If you're on natural gas — which most Houston-area homes are — a properly maintained whole-home standby generator can power your home through virtually any outage, from a 12-hour grid hiccup to a multi-week post-hurricane restoration. The fuel supply isn't the concern; the maintenance schedule is.

If you're on propane, size your tank appropriately for the outages your area typically experiences. For most of the Greater Houston area, a 500-gallon tank with a 20kW generator gives you a solid 5–8 days of runtime at normal summer loads — enough for most storm scenarios.

Not Sure What Size You Need for Your Home?

The right generator size depends on your home's square footage, your AC tonnage, and which appliances you need to run during an outage. We do a free load calculation during every in-home consultation — no guessing, no oversizing, no undersizing.

Call or text: 346-888-9393 Monday–Friday, 8 AM–5 PM Get Your Free Estimate →

We serve Houston, Tomball, Cypress, Katy, The Woodlands, Spring, Sugar Land, Conroe, Pearland, and surrounding areas.

PSL Technology LLC is an authorized dealer and certified installer of Generac and Briggs & Stratton standby generators. Licensed, permitted, and code-compliant installations across Greater Houston.