What Size Generator Can My Gas Meter Support?

Step 1: Find Generator Fuel Demand

Standby generator manuals usually publish natural-gas consumption in cubic feet per hour at specified load.

Larger generators can require hundreds of cubic feet per hour.

Step 2: Inventory Other Gas Appliances

Include:

• Furnace
• Water heater
• Dryer
• Range
• Fireplace
• Pool heater

Use appliance input ratings.

Step 3: Add the Loads

The system has to support the generator plus other appliances expected to operate during an outage.

Do not assume the furnace will be off just because the generator is running.

Step 4: Check Meter Capacity

The gas meter has a rated capacity.

But the utility should confirm whether the meter, regulator and service can support the proposed connected load.

Example

Suppose the home already uses:

• Furnace: 100,000 BTU/hr
• Water heater: 40,000 BTU/hr
• Range: 60,000 BTU/hr

Existing total:

200,000 BTU/hr

Then the generator adds another large load.

A 20kW+ generator can push total demand well beyond the original service design.

The example is illustrative only.

Use actual appliance ratings.

Cubic Feet vs BTU

A rough planning assumption is often:

~1,000 BTU per cubic foot of natural gas

Actual energy content varies.

The utility's calculation should control.

Why Meter Label Alone Is Not Enough

Even if the meter appears large enough, the system can still be limited by:

• Regulator
• Service line
• Branch pipe
• Pressure drop

You need the whole fuel path checked.

Can a 250 CFH Meter Support a 22kW Generator?

Do not answer this from the meter number alone.

You also need generator demand, existing appliance loads and utility service conditions.

Can I Just Turn Other Gas Appliances Off?

That is not a robust design.

A standby system should be sized for the loads expected to operate automatically.

High-Pressure Service Changes the Answer

Higher-pressure gas systems can support more capacity through smaller piping with local regulation.

Do not compare a high-pressure service with a standard low-pressure residential setup.

Who Makes the Final Call?

Use:

• Gas utility
• Licensed gas fitter
• Generator installer

The utility often owns the meter and controls service upgrades.