Water heaters · tankless gas

Tankless gas water heater cost

A gas instantaneous (tankless) water heater at UEF 0.87 has a certified national retrofit benchmark of $1,773.49 (2023 USD) low, $2,129.14 (2023 USD) typical, and $2,646.99 (2023 USD) high.

Source year. Based on the NREL REMDB Gas Inst class in 2023 dollars.

Geographic scope. United States national modelled benchmark.

Model scope. Gas tankless / instantaneous units. The workbook regression uses UEF only (0.81–0.99). There is no certified gallon input.

Important limitation. Not a storage-tank price, not electric tankless, and not a current plumber quote.

Certified benchmark values

Certified 2023 USD figures for this page. Missing bands are unpublished, not estimated.
Band	Value
installed low	$1,773.49 (2023 USD)
installed typical	$2,129.14 (2023 USD)
installed high	$2,646.99 (2023 USD)

Benchmark estimator

Results are modelled 2023 USD benchmarks, not a contractor quote.

Modelled benchmark: Low $1,773.49 (2023 USD); typical $2,129.14 (2023 USD); high $2,646.99 (2023 USD)

Formula: retail=3885.583326*m1(0.87)+0*m2(0)+-2098.322494; installed=retail*1+847.0100038353082. This modelled range is not a contractor quotation.

Source year: 2023 USD
Scope: Water Heater Gas Inst, national retrofit modelled in 2023 dollars
Limitation: Not a local contractor quote. Inputs outside the published bounds fail closed.
Basis: Water Heater Gas Inst retrofit modelled in 2023 dollars
Matches the certified evaluation point on this page.

What this estimate includes

UEF regression
Gas Inst retrofit adder

What moves the number

Uniform Energy Factor
Fuel and venting, which the equation does not itemize separately

Methodology and sources

Independent REMDB Gas Inst row.
Entering a tank size is not supported because the published equation has no volume term.

Primary source: National Residential Efficiency Measures Database 2024.

How to use this result when planning

The certified gas-instantaneous equation is UEF-only. There is no gallon field because the workbook has no volume term.
Stay inside UEF 0.81–0.99. The default evaluation is UEF 0.87.
Electric tankless and storage tanks are out of scope on this page.

Higher in-domain UEF

Keep the gas instantaneous class. Change only UEF from 0.87 to 0.95.

Engine result: Low $2,108.87 (2023 USD); typical $2,439.99 (2023 USD); high $3,039.39 (2023 USD). Formula: retail=3885.583326*m1(0.95)+0*m2(0)+-2098.322494; installed=retail*1+847.0100038353082. This modelled range is not a contractor quotation.

When to get a contractor quotation

Get a plumber quote when you know gas-line size, venting, and whether the existing water lines can handle a tankless swap.
If the bid includes a gas-line upsize, that work is not inside this UEF regression.

Limitations

2023$ historical REMDB retrofit benchmark, not a 2026 contractor quote.
REMDB may include upstream RSMeans/retail-derived inputs; cite REMDB only.
Gas instantaneous / tankless UEF-only regression. Not a storage-tank total.

Questions this evidence can answer

Can I enter gallons?

No. The certified tankless equation is UEF-only. Gallon inputs would be decorative, so they are not offered.