Gas Tankless Water Heater Costs

$1,400 – $2,900 Installed

The average cost of a natural gas tankless water heater is around $700 when installed yourself. Adding in supplies and labor, the installed cost of a tankless system is approximately $2,235.
Average DIY
Average Pro
Typical Range
$1,400 – $2,900
Low End
$650 (DIY)
High End
$3,800 (Pro)
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Last Updated: Friday, December 18, 2020

How Much Does a Tankless Water Heater Cost?

$950 – $2,200
Average Cost Estimate
$1,400 – $2,900
$2,100 – $3,800
Water Flow Rate 2-5 GPM 5-7 GPM 8-10 GPM
Unit Efficiency 80-85% 90% and Above 95% and Above
Unit Cost $250 – $500 $500 – $750 $750 and Up
Install Supplies Cost $200-$550 $200-$550 $200-$550
Labor Costs $450 – $850 $650 – $1,300 $1,100 – $1,750
Permit & Inspection $60 – $300 $60 – $300 $60 – $300
Other Supplies $60 – $300 $60 – $300 $60 – $300

Sections: Overview | Product Costs | Installation Cost | DIY or Pro | Web Compare | Shared Pricing

tankless water heater installed

Overview of Tankless Water Heaters

These space saving and energy efficient water heaters are making their way into more homes every year, in both new construction and replacement. They are smaller in physical size and take up much less space than tank-style water heaters. While many offer higher operating efficiency, the also-higher purchase and installation cost can make them cost prohibitive compared to than conventional water heaters.

In this Costimate, we’ll help you learn about the cost for both gas and propane water heaters. We’ll provide a comparison of tankless unit pricing factors, installation cost, as well as retail versus installed prices, and a section where homeowners have provided the installation details of their own. You’ll also learn whether or not others feel that tankless water heater installation is a DIY or Pro project.

Cost Breakdown and Price Factors

Tankless Water Heaters

The most expensive physical item is going to be the tankless water heater cost itself, and some Pro’s say it’s best to spend extra money on the highest efficiency gas model your budget will allow.  Several factors will determine which unit you need to buy, and you should consult with a plumber, or do your own research on the hot water demands of your home, number of appliances like a dishwasher or faucets, type of installation, showers and bathtubs, number of units you may need, etc.

Regardless of how you learn about the model that is best for your home and usage needs, most areas require the use of a plumber to handle all or part of the installation due to plumbing, inspection, and local building code.

  • Size of Unit (BTU’s) – Higher BTU output water heaters cost more money, but service more fixtures.
  • Flow Rate (GPM) – Higher water flow rates as they relate to temperature rise cost more, but also service more fixtures.
  • Efficiency of Unit (AFUE) – Higher efficiency water heaters save more money when used, but cost more at the register.

Cost of Installation Supplies

Along with the unit cost, you’re also going to need additional supplies to help complete the installation. A plumber will likely provide smaller fittings inclusive of the project estimate.

  • $35 – $100 | Copper, Pex or Poly Pipe
  • $15 – $50 | Misc Pipe Fittings, Valves, Supplies, and Connectors
  • $40 – $200 | PVC or Concentric Venting Kit (Indoor installations)
  • $40 – $250 | Electrical Wire and Circuit Breaker (If needed)
  • $20 – $26 / Foot | New Gas Line if Needed
  • $70 – $100 | Miscellaneous: Mounting supplies, wood, drywall, caulking and sealants, etc.

Permits, Inspection, and Installation Labor Costs

After purchasing the water heater unit and supplies, you still have to factor the cost to install your complete system. Handy homeowners might consider this as a DIY project, but before you touch anything you should consult a licensed plumber. There are very likely to be code requirements, as well as water supply, gas supply, venting, and electrical considerations that are well known by professionals.

Permits and Inspection

  • $35 – $150 ea. | Plumbing, Electrical and Gas Inspection(s)
    Since almost all tankless water heater installation will require connecting to 2 or 3 three utilities, (gas, water, electric) its not uncommon that each will need to have its own inspection per local ordinances.

Installation Cost and Time

While some plumbers do have flat rate pricing for different projects, tankless installation is usually handled on a time and material cost basis. If 2 plumbers show up at your home, you can assume one is licensed and the other is an apprentice. If paying by the hour, you will be charged cumulatively for both.

  • $60 – $90 per-hour | Licensed and Insured Plumber
  • $40 – $75 per-hour | Plumbers Apprentice and Helper

Completed Installation Time

When you calculate time for a project, the following factors need to be taken into consideration.

  • 2-4 hours | Simple Installation, Replacement
    Outdoor, exterior utility closet, or garage installation. Easy access to utilities, simple venting, or a direct replacement..
  • 4-8 hours | Most Common Installation
    Indoor or basement unit location, average connections to gas, water and electric, venting through roof or wood sidewall.
  • 8-12 hours | Difficult Installations
    Attic installations, larger gas line requirements, significant water line changes, long runs of electric service, venting through roof, block or concrete foundation wall.

DIY or Hire a Pro


In my opinion, unless you have very good plumbing skills with knowledge of the tools and skill required to get the system installed to local code and inspected, leave it to a licensed plumber.

  • Requires many specialty tools and skills. (soldering, brazing, etc)
  • You need to be fairly knowledgeable in plumbing, electric, structural.
  • You need to get inspections by local/state officials.
  • Improper installation can cause damage and possibly lives. (gas leak, flood, fire, carbon monoxide poisoning, etc)

Trying to do this type of project yourself could easily outpace the installation cost when handled by a licensed plumber. I consider myself an 8/10 on the handyman scale, and I would hire a pro to do this job every time.

I Suggest a Pro, What do you think?

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Installed Costs from Around the Web

In our efforts to provide the true cost of installing a tankless water heater, we regularly gathered pricing from around the web as well.

Cost Range
$1,400 – $2,900
CostHelper $3,150
$1,800 – $4,500
$300 – $3,500
Suggest a Cost Comparison from Another Website


Costs Submitted by Homeowners and Pro’s

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