InstaBidsCost for a tankless water heater?
This survey has no tankless water heater installation-specific figure. The figure below covers all "Added or replaced water heater" jobs, so read it as context, not as the price of tankless water heater installation alone.
Context: all "Added or replaced water heater" jobs
$1,300 was the median homeowner survey figure for all “Added or replaced water heater” jobs, not tankless alone, for data years 2021-2023 in the United States. The full “Added or replaced water heater” category, rather than tankless alone, had a typical range (middle half of 1,522 American Housing Survey data points, the United States, 2021-2023) of $850 to $2,000.
Updated 2026-11-03
InstaBids is an AI-run marketplace for homeowners and property managers: describe a home job once, by chat or through your own AI assistant, add photos, and get multiple written quotes on the same scope, compared apples to apples, with no phone calls or home visits before you pick.
For homeowners, property managers, landlords and HOA boards.
| What was measured | Median | Typical range (middle half) |
|---|---|---|
| The full “Added or replaced water heater” category, rather than tankless alone, had | a median of $1,300 | the typical range (middle half of 1,522 American Housing Survey data points, the United States, 2021-2023) was $850 to $2,000 |
How measured: hired-out finished jobs, survey-weighted, not adjusted for inflation. Source: U.S. Census Bureau, American Housing Survey 2023, data read 31 October 2026.
These figures are estimates from U.S. Census Bureau, American Housing Survey 2023, data years 2021-2023, read 31 October 2026, for the United States. They are not a quote, and they are not a promise of what any contractor on InstaBids will charge. Your price depends on your home, the materials and the contractor. Get written bids before you decide.
- Describe it onceBy chat, or through your own AI assistant, and add photos.
- Post it and send itContractors bid in writing on that scope.
- Compare line by lineEvery quote is written against the same scope.
- You chooseContact details stay hidden until you pick and they confirm.
For your AI assistant
MCP connector · REST API · plain HTMLHand any of these to your assistant and it can help you write this job's request; you send the request yourself. What you type in the job box above goes into the prompt these buttons carry. The connector asks you to sign in to your InstaBids account the first time.
- MCP connector URL
https://instabids.ai/api/agent/mcp - Agent API (OpenAPI)
https://instabids.ai/openapi.json - Start-request link
https://instabids.ai/intake?from=cost-tankless-water-heater-install&utm_source=us&utm_medium=page&utm_campaign=cost&page_type=cost&job=tankless+water+heater+install - Prompt for any AI, with your job
- ChatGPTOpens with the prompt
- ClaudeOpens with the prompt
- GrokOpens with the prompt
- GeminiCopies the prompt, then opens
Every page is plain HTML. Steps for every assistant: add to your assistant.
What size tankless water heater do I need?
U.S. Department of Energy, Home Improvement Expert checklist: “The water heater shall be sized based on the maximum demand anticipated and the temperature rise needed (which depends on climate).”
Source: U.S. Department of Energy, Home Improvement Expert checklist, read 31 October 2026.
ENERGY STAR: “Shower and Bathtub - 2.5 GPM”
Source: ENERGY STAR, read 31 October 2026.
ENERGY STAR: “Clothes Washer - 3.3 GPM”
Source: ENERGY STAR, read 31 October 2026.
Put the household hot water needs in your InstaBids job, and plumbers bid in writing on that unit size.
What are the tankless water heater installation requirements?
U.S. Department of Energy, Home Improvement Expert checklist: “The contractor shall determine whether the water heater model to be installed requires an outlet or a hard-wired power supply, confirm the availability of an electrical outlet or supply near the location for the water heater, and install an outlet if necessary.”
Source: U.S. Department of Energy, Home Improvement Expert checklist, read 31 October 2026.
U.S. Department of Energy, Home Improvement Expert checklist: “Collection and disposal of combustion condensate shall be provided if necessary.”
Source: U.S. Department of Energy, Home Improvement Expert checklist, read 31 October 2026.
Describe the install site, gas or electric supply and venting once on InstaBids for every plumber to see.
What does gas tankless water heater installation involve?
U.S. Department of Energy, Home Improvement Expert checklist: “The existing gas service line shall be inspected to determine if the size is adequate for the tankless gas water heater. If not, the gas line shall be replaced with one of adequate size.”
Source: U.S. Department of Energy, Home Improvement Expert checklist, read 31 October 2026.
ENERGY STAR: “Your installer may need time to order the proper model, and it may take longer to install than a standard water heater.”
Source: ENERGY STAR, read 31 October 2026.
A gas tankless job can be posted on InstaBids with the gas line and venting work spelled out.
What tankless water heater venting code applies?
Daly City, California, Building Division: “Generally, tankless water heaters must be vented independently through category III (stainless steel) venting systems.”
Source: Daly City, California, Building Division, read 31 October 2026.
Daly City, California, Building Division: “Tankless water heaters must be installed in accordance with the manufacturer's installation instructions.”
Source: Daly City, California, Building Division, read 31 October 2026.
Name the venting route in the scope you post on InstaBids, so each written bid covers the same vent.
Do you need a permit for a tankless water heater?
Daly City, California, Building Division: “Permits for tankless water heaters require that a gas piping schematic or plan of the gas-piping layout be submitted for review.”
Source: Daly City, California, Building Division, read 31 October 2026.
Daly City, California, Building Division: “At the time of permit application, a gas pipe sizing diagram must be submitted to demonstrate the gas piping is adequately sized for the increased demand created by installation of a tankless water heater.”
Source: Daly City, California, Building Division, read 31 October 2026.
Ask in your InstaBids description who pulls the permit, and each plumber answers it in writing.
How long does a tankless water heater last?
U.S. Department of Energy, Building America Solution Center: “Tankless water heaters are generally considered to last up to 20 years, compared to 10–15 years for tank-type water heaters (IBACOS 2012).”
Source: U.S. Department of Energy, Building America Solution Center, read 31 October 2026.
Write the model and service you want into your InstaBids job, and you choose who gets your number.
What tankless water heater installation includes
Where a quote below names a city or county, it is that office's own rule, shown as one example; the permit office for your home may set different rules.
| What the source says | Where it comes from |
|---|---|
| U.S. Department of Energy, Home Improvement Expert checklist: “The water heater shall be sized based on the maximum demand anticipated and the temperature rise needed (which depends on climate).” | U.S. Department of Energy, Home Improvement Expert checklist, read 31 October 2026. |
| U.S. Department of Energy, Building America Solution Center: “Determine location of water heater. If gas, ensure that required clearances for the equipment and venting are met. If a condensing unit, confirm that a means for removing the condensate is provided that meets local code requirements.” | U.S. Department of Energy, Building America Solution Center, read 31 October 2026. |
List the tankless choices above in your InstaBids job, and plumbers bid in writing on that install.
Line items a written bid should list
- U.S. Department of Energy, Home Improvement Expert checklist: “The existing gas service line shall be inspected to determine if the size is adequate for the tankless gas water heater. If not, the gas line shall be replaced with one of adequate size.”
Source: U.S. Department of Energy, Home Improvement Expert checklist, read 31 October 2026.
- U.S. Department of Energy, Home Improvement Expert checklist: “The contractor shall determine whether the water heater model to be installed requires an outlet or a hard-wired power supply, confirm the availability of an electrical outlet or supply near the location for the water heater, and install an outlet if necessary.”
Source: U.S. Department of Energy, Home Improvement Expert checklist, read 31 October 2026.
- U.S. Department of Energy, Home Improvement Expert checklist: “Collection and disposal of combustion condensate shall be provided if necessary.”
Source: U.S. Department of Energy, Home Improvement Expert checklist, read 31 October 2026.
- U.S. Department of Energy, Home Improvement Expert checklist: “All operation and maintenance procedures shall be reviewed with the homeowner.”
Source: U.S. Department of Energy, Home Improvement Expert checklist, read 31 October 2026.
Tankless bids on InstaBids come in writing, so the items above become a list to read each bid against.
How to compare written bids like for like
Ask every contractor to bid in writing on the same line items listed above, then compare the written bids line by line.
ENERGY STAR: “Request cost estimates in writing.”
Source: ENERGY STAR, read 31 October 2026.
Plumbers on InstaBids all bid on the one tankless scope you posted, so you compare plumbers, not jobs.
Get written bids
Contractors who take part bid on one written scope card, so nobody visits before you see any prices.
Sources for the figures on this page
- U.S. Census Bureau, American Housing Survey 2023, https://www.census.gov/programs-surveys/ahs/data/2023/ahs-2023-public-use-file--puf-.html, read 31 October 2026. U.S. government work; no endorsement implied.
- U.S. Department of Energy, Home Improvement Expert checklist, basc.pnnl.gov/home-improvement-expert/checklists/gas-tankless-water-heater, read 31 October 2026.
- ENERGY STAR, www.energystar.gov/products/whole_home_tankless_gas_water_heaters, read 31 October 2026.
- Daly City, California, Building Division, dalycity.org/219/Water-Heaters, read 31 October 2026.
- U.S. Department of Energy, Building America Solution Center, basc.pnnl.gov/resource-guides/gas-fired-tankless-water-heaters, read 31 October 2026.