Repair or Replace a Water Heater: Calculator

Repair a water heater when it is still well within its expected life and the repair costs less than half the price of a new, installed unit. Lean toward replacing it when the repair would cost more than half, and consider replacing it once a tank heater is 10 years old. The cost part is This Old House’s rule: “Generally, when repair costs exceed half the price of a new unit, replacement becomes the more economical choice.” The 10-year mark comes from ENERGY STAR and This Old House. By our rule of thumb, a leaking tank also points to replacement. Enter your heater’s type, age and repair quote below to see where you land.

How the calculator decides

The calculator runs its checks in this order and stops at the first one that applies. Some rules come straight from the sources; where we filled a gap, it says “our rule of thumb.”

1. Safety first. If you smell gas, water is coming from the relief valve or its pipe, or there’s water near outlets or appliances, the calculator shows safety steps instead of a recommendation.
2. Is the tank itself leaking? → “Plan to replace.” This applies when water is coming from the tank body, not a valve or a pipe connection. It’s our rule of thumb, based on Fixr’s note that tanks corroded on the inside “usually need to be replaced. There’s no way to undo corrosive damage.” Fixr also lists tank repairs ($250–$1,000), where a damaged tank “may need to be patched up to prevent leaks,” so our rule is the more cautious one. A plumber should confirm where the water is coming from first, because a leaking drain valve ($100–$200 to replace, per Fixr) is a much smaller job (see water heater leaking from the bottom).
3. Does the repair exceed half the price of a new unit? → “Replacement is likely the better buy.” This is This Old House’s rule. If you don’t have a replacement quote yet, the calculator uses the middle of Fixr’s installed price range for your type (our rule of thumb, not an average from Fixr).
4. Has it reached its age threshold? → “Consider replacing.” For tank heaters, gas or electric, the threshold is 10 years, as ENERGY STAR advises: “If you suspect your water heater is more than 10 years old—it is time to consider replacing it.” For tankless units it is 15 years, the low end of the “15 to 20 years or more” Rheem gives, and for heat pump units 13 years, the lifespan ENERGY STAR assumes in its savings math. Those two thresholds are our rule of thumb.
5. Is it close to the line? → “Repair, but start planning a replacement.” This applies when the repair is 30–50% of the replacement price, or the heater is two years or less from its age threshold (our rule of thumb).
6. Otherwise → “Repair makes sense.” This Old House says “minor issues in newer units warrant repairs.”

Treat the age thresholds as a starting point, not a deadline. The sources disagree on lifespan. For tanks, Rheem, This Old House and Fixr’s installation guide say 8–12 years, Fixr’s repair guide says “around eight to ten years,” and a 2009 U.S. Department of Energy fact sheet says 10 to 15 years. For tankless heaters, that DOE fact sheet says “more than 20 years,” and ENERGY STAR gives “a life expectancy of 20 years,” so our 15-year threshold is on the cautious side. More detail on how long water heaters last.

When repair makes sense

This Old House says “a failing pilot light, faulty heating element, or thermostat problems usually don’t require a full replacement,” and that “minor issues in newer units warrant repairs.” Fixr’s prices for common jobs, labor included:

Fixr puts the average water heater repair at $150 to $750; This Old House says minor issues “often have simple fixes costing $150–$500.” Compare your quote with the replacement prices in the next section. All of these are jobs for a licensed plumber, not DIY.

When replacement makes sense

This Old House puts it this way: replacing “usually makes financial sense when repair costs exceed more than half of the replacement cost or the unit is 10 or more years old.” Other signs it lists: rusty water, several repair calls within a year, visible rust on the tank, water pooling around the base, and not enough hot water for your household. Fixr suggests a new heater may be the better value once a repair quote reaches $1,000 or more.

What a new heater costs:

The two guides use different data, so treat each column on its own terms. This Old House’s tank figure varies with size, too: its table runs from $600–$1,200 for a 40-gallon tank to $1,000–$3,000 for 80 gallons. Fixr’s repair guide prices replacing the tank itself at $600–$2,000 and notes that in some cases “it’s a better value to get a new heater installed instead.”

ENERGY STAR warns that after a sudden failure you may have to schedule an urgent replacement that “can be more expensive” and may “limit your replacement options to inefficient models.”

Other factors: warranty, efficiency, fuel type

Warranty. Check it before paying for a repair. Fixr says most brands offer a 6- to 12-year warranty that usually covers the tank and replacement parts, that most manufacturers also offer a one- or two-year labor warranty, and that you “might be able to claim on the warranty and pay less for repairs.” ENERGY STAR-certified models must carry a warranty of at least 6 years (on the system, the sealed system, or the heat exchanger, depending on type).

Efficiency. A new heater can cost less to run. ENERGY STAR’s heat pump page says a certified heat pump water heater can save a household of 4 “approximately $550 per year” on electric bills compared with a standard electric water heater; another ENERGY STAR article puts it at “more than $330 per year.” That changes the math on an old electric tank, but these are household-of-four estimates, not a quote for your home.

Fuel type. Replacing your heater with a similar-size unit on the same fuel is “usually the most affordable option upfront,” Fixr says. Switching costs more: This Old House says converting from electric to gas “requires installing new gas lines, adding $1,500–$2,300.”

Safety first

The calculator is for planning, not for urgent problems. If you smell gas, leave the house and call your gas utility or 911 from outside. Never plug or cap a leaking relief valve; see pressure relief valve leaking. With no hot water at all, start with no hot water: what to check.

Sources

• This Old House — How Much Does Water Heater Installation Cost? (updated Jun 17, 2026; cost data from The Home Depot and market research)
• Fixr — Water Heater Repair Cost (updated Aug 29, 2025)
• Fixr — How Much Does It Cost to Install a Water Heater? (updated Jan 27, 2026)
• ENERGY STAR — When Should You Replace Your Water Heater? (Feb 2, 2024)
• ENERGY STAR — Save More with ENERGY STAR Certified Heat Pump Water Heaters (undated; accessed Oct 31, 2026)
• ENERGY STAR — Save More with ENERGY STAR Gas Tankless Water Heaters (undated; accessed Oct 31, 2026)
• ENERGY STAR — Water Heater Key Product Criteria (undated; accessed Oct 31, 2026)
• U.S. Department of Energy, Building America — Tankless Water Heaters fact sheet by CARB / Steven Winter Associates (last update Aug 18, 2009; still on a DOE server), p. 1
• Rheem (manufacturer) — Tank vs. Tankless Water Heater Lifespan Comparison: What to Expect Long-Term (Mar 5, 2026)

Checked 2026-10-31