Water heater sizing Last reviewed June 2026

What Size Water Heater for Electric vs Gas Homes?

By the WhatSize editorial team 4 min read Standards-reviewed

TL;DR

Choose electric water heaters (40-80 gal) for homes without natural gas — they're cheaper upfront but cost more to operate. Choose gas water heaters (30-60 gal) if you have natural gas — they heat water faster and cost 30-50% less to run.

Looking for a different size? See What Size Water Heater for a 1-2 Person Household? or browse all water heater sizing guides.

Electric vs Gas: Not Just a Fuel Decision

The choice between electric and gas water heater affects sizing, cost, and installation requirements. Electric tanks are physically larger because they need more internal space for heating elements, while gas tanks have a smaller footprint due to the powerful gas burner at the bottom.

For sizing: a 40-gallon gas water heater provides similar hot water availability (First Hour Rating) as a 50-gallon electric model, because gas heats water faster. So if you're switching from electric to gas, you may be able to go down one tank size. However, always check the FHR (First Hour Rating) label — it's more important than the tank size.

Operating costs vary significantly by location. National averages: electric water heaters cost $400-600/year to operate, gas water heaters cost $200-350/year, and hybrid heat pump water heaters cost $150-250/year.

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Electric vs Gas Sizing Guide

Electric — 1-2 people: 40 gallon ($400-500 upfront, $400-500/yr operating)
Electric — 3-4 people: 50 gallon ($500-600, $450-550/yr)
Electric — 5-6 people: 60-80 gallon ($600-900, $500-650/yr)
Gas — 1-2 people: 30 gallon ($500-700 upfront, $200-300/yr operating)
Gas — 3-4 people: 40 gallon ($600-800, $250-350/yr)
Gas — 5-6 people: 50-60 gallon ($800-1,000, $300-400/yr)
Hybrid heat pump — 3-4 people: 50 gallon ($1,000-1,200, $150-250/yr) — best long-term value

Frequently asked questions

What size water heater for an electric vs gas home?

Yes, but it requires significant modifications including running a gas line (by a licensed plumber/gas fitter), installing a vent pipe for exhaust, and possibly upgrading the gas meter. Budget $1,000-2,500 for conversion labor.

How long do electric vs gas water heaters last?

Both last about 8-12 years with proper maintenance. Gas water heaters often last slightly longer because they have fewer components that can fail. The anode rod should be inspected every 3-5 years and replaced if heavily corroded.

Is a heat pump water heater worth the higher upfront cost?

Heat pump water heaters cost 2-3x more upfront ($1,000-1,500 vs $500 for standard electric) but use 60% less electricity. Over a 10-year lifespan, the energy savings of $200-350/year more than make up for the higher purchase price.