Water Heater Cost Calculator

A like-for-like electric swap runs about $1,400 installed — $1,120 to $1,890 depending on the market. The same 40-gallon job in gas, with the flue reconnected, is roughly $1,830. Add the expansion tank, permit and haul-away most codes now expect and the realistic planning number is about $1,920, right inside HomeGuide's $600–$3,100 installed range for standard tanks.

Yes, in nearly every US jurisdiction — a water heater is a plumbing and (for gas) fuel-gas appliance, and an unpermitted install can fail a home sale inspection. Permits run $25–$300 depending on the type of unit (HomeGuide lists $50–$200; Angi/HomeAdvisor data $25–$300, plus the same again if a new gas line is involved). Most plumbers pull the permit for you and pass the fee through — that's the $150 line in this calculator.

Usually, yes. When a check valve or backflow preventer closes your supply system, heated water has nowhere to expand and pressure spikes that stress valves and fittings — which is why most modern codes require a thermal expansion tank on a replacement. Installed cost is about $220 here, inside the $100–$400 HomeGuide and $90–$350 Angi ranges. Skipping it on a permitted job fails inspection.

The gas unit itself is only $100–$200 more (HomeGuide's figure), but gas adds venting: an atmospheric reconnect is modest, while a power-vent model needs a blower plus $300–$500 of electrician wiring (per Angi/HomeAdvisor data compiled by Bob Vila). Electric tanks vent through nothing, so the install is cheaper. Operating costs run the other way — gas usually beats electric per gallon of hot water — and converting fuels adds a $275–$825 gas line or $550–$2,300 of wiring.

HomeGuide puts tank life at 8–12 years; contractors compiling the Bob Vila guide say 10–15 with good maintenance. The repair-or-replace call is symptom-driven: water pooling at the tank's base means the glass liner has cracked and no repair exists — replace it; rusty or metallic-tasting hot water means the anode rod has lost the fight with corrosion and the tank is on borrowed time; rumbling means sediment, which a flush can still fix on a younger unit. Replacing the $30–$60 anode rod around year 5 and flushing sediment annually are the two moves that stretch a tank toward the top of its range — on a unit already past 10 years, put that money toward the replacement instead.

HomeGuide's sizing table: 1–2 people, 23–36 gallons; 2–3 people, 36–46; 3–4 people, 46–56; 5 or more, 56–80. The most common replacement in the US is 40 gallons, and matching your old tank's size is usually right unless the household changed. The sharper sizing metric is the First Hour Rating on every unit's yellow EnergyGuide label — the gallons it delivers in your single busiest hour, which you can compare against a real morning of back-to-back showers plus the dishwasher. Oversizing costs you at purchase and every month after in standby losses; a hybrid heat pump at 50–65 gallons covers most families of five.

A relocation isn't a swap — the crew extends or re-routes water, gas and vent lines, may add a drain pan and new seismic bracing, and patches whatever the old run cut through. HomeGuide prices a tank relocation at +$500–$2,500 with supply piping at $12–$15 per linear foot; this calculator models $500 for a move within the room and $1,500 for a new location.

Installed, a 50-gallon hybrid lands around $3,550 in this model — inside HomeGuide's $2,000–$4,600 range for hybrid installs — versus roughly half that for a standard electric tank. It uses about a quarter of the electricity by moving heat instead of making it, but it needs ~1,000 cubic feet of air between 40°–90°F to work efficiently (ENERGY STAR's siting guidance), so closets need louvered doors. Check ENERGY STAR's rebate finder before buying: utility and federal incentives routinely knock hundreds off the premium.