Water Heater Replacement Cost Calculator

Understanding your result

The headline is the installed price range after rebates, with the midpoint and the heater described in the sub-line. The stats give the low, midpoint and high. The table shows the heater installed, the conversion or fuel-change work, the permit, the totals before and after rebates, and the sources.

The conversion line is the one that separates a like-for-like swap from a bigger job. Converting a gas tank to a gas tankless unit almost always needs a larger gas line and new venting, and changing fuel needs either a gas line and venting or a new 240 V circuit; tick the right option so the range includes it.

The size comes from the tank size calculator, or the tankless size calculator for a tankless unit. The running cost calculator shows what each type costs a year to run, and the upgrade payback calculator combines the two to show whether a more efficient heater pays back.

How we calculate this

The type ranges are a 2026 contractor price list (gas tank $900 to $1,800, electric tank $700 to $1,500, gas tankless $2,500 to $4,500, electric tankless $1,500 to $3,000, heat pump $1,500 to $4,000), consistent with HomeAdvisor’s 2025 ranges (tank $600 to $2,500, tankless $1,400 to $3,900, heat pump $1,200 to $3,500). The size, region and conversion factors are our estimates, set out here so they can be checked, and the permit range is from 2025 cost guides. The UEF ratings that decide running cost are on the efficiency ratings table.

The assumptions behind the numbers

Assumptions last reviewed October 8, 2026.

The calculator does not include moving the heater to a new location, a new expansion tank or drain pan where they were missing, a chimney liner when a gas water heater is left alone in an old chimney, water damage repair from a failed tank, or electrical service upgrades for whole-house electric tankless units. The guide to water heater running costs compares the types over their life, and the guide to what HVAC installations cost puts water heaters next to the rest of the mechanical system.

Two worked examples

Where to find your inputs

Type and size. From the tank size or tankless size calculator, and the space and fuel available.

What it replaces. The old heater’s rating plate gives its fuel and size.

Rebates. Your utility, your state energy office and the ENERGY STAR rebate finder; heat pump water heaters are the most commonly rebated.

Region. High for the Northeast, California, the Pacific Northwest and big metros.

Common mistakes

• Pricing a tankless conversion as a swap. The gas line and venting are most of the extra.
• Replacing with the same size by habit. Size by the first-hour rating.
• No expansion tank. Many codes now require one on closed systems.
• Skipping the permit. Gas connections and relief valves should be inspected.
• A heat pump water heater in a closet. It needs air volume or ducting.
• Waiting for the tank to fail. A burst tank can do more damage than the heater costs.

Questions people ask

How much does it cost to replace a water heater?

HomeAdvisor puts the average 2025 replacement at $1,333, with most homeowners paying $882 to $1,810. By type, a gas tank costs about $900 to $1,800 installed, an electric tank about $700 to $1,500, a gas tankless unit $2,500 to $4,500 and a heat pump water heater $1,500 to $4,000 before rebates, according to a 2026 contractor price list. A 50-gallon gas tank with a permit comes to about $1,000 to $2,200 in the calculator.

How much does it cost to switch from a tank to a tankless water heater?

The tankless unit itself, installed, is about $2,500 to $4,500 for gas; converting from a tank usually adds $1,000 to $2,500 for a larger gas line, new venting and re-plumbing, so the total is about $3,550 to $7,200. One plumbing company puts the conversion work at $1,800 to $2,500. The calculator's range is widened down for simple cases where the existing gas line is already large enough.

Is a heat pump water heater more expensive to install?

Somewhat. A heat pump water heater costs about $1,500 to $4,000 installed, against $700 to $1,500 for a standard electric tank, and may need a 240 V circuit and a condensate drain. It often qualifies for state and utility rebates of several hundred dollars, and it saves about $500 a year in electricity for a family compared with a standard electric tank, so the extra cost usually pays back in two to five years.

How long does a water heater last?

Tank water heaters typically last 8 to 12 years; tankless units 15 to 20; heat pump water heaters 10 to 15. Signs of the end include rust-coloured hot water, a rumbling tank (sediment), water around the base, and an age over 10 years on the rating plate. Replacing before a tank fails avoids the water damage of a burst tank, which can cost more than the heater.

Do I need a permit to replace a water heater?

In most US jurisdictions, yes; permits typically cost $50 to $200. The inspection checks the gas connection and venting, the temperature and pressure relief valve and its discharge pipe, the expansion tank where required, seismic strapping in earthquake zones, and the electrical connection. Licensed plumbers usually pull the permit as part of the job.

What size water heater should I replace mine with?

Not necessarily the same size. Size by the household's busiest hour of hot water use and the first-hour rating, which the tank size calculator works out. A household that has shrunk can go smaller and save on standby losses; one switching from gas to electric or heat pump usually needs a larger tank, because electric recovery is slower.