THE HOMEOWNER’S PLANNING DESK

Natural Gas vs. Propane Planner

Compare documented consumption, local fuel prices, outage scenarios and stored-propane inventory.

Planning estimate

By Standby Generator Guide Editorial Team · Published October 5, 2026 · Updated October 6, 2026 · Method and source checks October 5, 2026

Planning estimate — confirm scope, prices and operating assumptions with qualified installers and fuel suppliers. Tools prepare questions and scenarios; they do not approve an electrical or fuel-system design.

Technical professional review pending.How this guide is reviewed

Prepared by our editorial research desk using linked sources. No licensed professional signoff or hands-on testing is claimed. See the review process and what remains to be reviewed.

These tools need JavaScript for calculations. The sizing worksheet and quote checklist remain available without it.

Manufacturer test point or your documented rate

Custom rates require a model-specific source. Enter the source and conditions below. Selecting a model does not confirm that it can support your home.

Custom source / load and test conditions

Generator planning size (kW)One outage scenario (hours)Total outage hours per yearNG use at selected load (ft³/hour)LP use at selected load (US gallons/hour)Local NG variable price ($/therm)Local propane price ($/US gallon)NG heat content (BTU/ft³)Propane tank nominal capacity (US gallons)Starting liquid fill (% of nominal)Reserve liquid level (% of nominal)Annual maintenance budget (USD)

Prefilled hours, tank levels and heat content are editable scenario assumptions. Use your utility’s billed heat content and delivered marginal fuel rates. Tank runtime is an inventory calculation only; your supplier must confirm usable capacity, safe fill, vaporization and refill reserve.

Two fuel paths, different outage constraints

Natural gas

Utility network → meter / regulator

Sized fuel piping → generator

Propane

Stored liquid → available vapor

Regulation / fuel piping → generator

Conceptual fuel paths only. Installer and supplier must verify pressure, capacity, piping, vaporization and applicable requirements. No installation dimensions are prescribed.

What can change this estimate?

Published consumption reflects a manufacturer’s test point, not a universal real-world rate. A 50% test point on propane can represent different delivered kW from 50% on natural gas. We do not interpolate between test points. Size input describes your scenario; it does not scale the selected test data.

Natural-gas delivery can be interrupted; ask the utility and installer to check meter, regulator, pressure and combined appliance demand. Propane availability depends on stored inventory, deliveries and cold-weather vaporization. Usable stored gallons do not guarantee the engine can draw enough vapor.

Fuel and maintenance totals exclude purchase, installation, tank rental, new utility fixed charges, exercise fuel, price escalation, repairs and financing. Include these separately in the ownership planner. Read the fuel decision guide.

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