Gas Tankless Water Heater Installation Cost in 2026

$2,100–$5,600
Natural gas installed
$2,500–$6,000+
Propane installed
$700–$1,995
Unit cost range
$600–$1,850
Labor cost

Complete Gas Tankless Cost Breakdown

Cost ComponentRangeNotes
Unit (whole-house gas)$700–$1,995Rinnai/Navien top end; Rheem/Bosch lower end
Labor — standard install$600–$1,200Direct swap, compatible venting, no gas work
Labor — with venting work$800–$1,500New vent run through wall/ceiling
Venting materials$200–$600Direct, power, or concentric vent kit + pipe
Gas line upgrade (if needed)$300–$800Upsizing existing supply line; not always required
Condensate drain (condensing)$75–$200Only for high-efficiency condensing units
Permit$50–$250Required in most US jurisdictions for gas work
Old unit removal/disposal$50–$150Often included in labor quote

Natural Gas vs Propane: Cost & Considerations

Natural Gas
$2,100–$5,600installed
Running cost: $25–$60/month
Pros
  • Lower operating cost than propane
  • Consistent utility pricing
  • Most installer experience
Cons
  • Not available in rural areas
  • Gas line upgrade often needed
  • Cannot convert to propane easily
Propane
$2,500–$6,200installed
Running cost: $35–$90/month
Pros
  • Available anywhere (rural areas)
  • Same tank unit, different orifice
  • Higher BTU per unit than NG
Cons
  • Higher operating cost than NG
  • Tank rent/ownership cost
  • Price volatility
Propane operating cost note: Propane typically costs 2–3× more per BTU than natural gas. If you have access to natural gas, the operating cost savings over 10 years often justify the modest extra installation cost of running a gas line vs staying on propane. See savings guide →

Gas Tankless Water Heater Cost by Brand

BrandUnit CostBTU RangeInstalled TotalWarranty (HX)Best For
Rinnai$500–$1,700120K–199K$2,500–$4,50012 yearsReliability-first buyers
Navien$1,075–$1,535150K–199.9K$3,900–$7,20015 yearsHighest efficiency
Rheem$500–$1,200150K–199K$1,800–$4,00012 yearsBudget-conscious; HD/Lowe's buyers
Noritz$600–$1,400120K–199.9K$2,500–$4,80012 yearsRinnai alternative; commercial use
Bosch$500–$1,100120K–167K$2,200–$4,00010 yearsNon-condensing direct swaps

See full brand comparison with reliability ratings and where to buy →

Labor Cost Detail: What You're Paying For

Labor is the most variable cost in a gas tankless installation. A standard direct-swap job takes 3–5 hours; complex installations with new gas and vent runs can take 2 full days. Here's what a comprehensive quote should include:

Standard install scope
  • Remove old unit and dispose
  • Mount new unit
  • Connect existing water lines
  • Connect to existing gas line
  • Commission and test unit
  • Instruct homeowner on operation
Potential extra charges
  • New vent run ($200–$600)
  • Gas line upsizing ($300–$800)
  • Condensate drain ($75–$200)
  • New water lines ($100–$300)
  • Permit fees ($50–$250)
  • Emergency/weekend rate (+25–50%)
Contractor pricing tip: Labor rates for the identical job vary 40–60% between contractors. Always get 3 quotes specifying the exact model number and full scope of work. Compare quotes line-by-line — a low total quote may exclude venting or permits that others include.

Frequently Asked Questions

Condensing units extract heat from exhaust gases before venting, achieving 90–98% efficiency (EF/UEF 0.90–0.98). They require a condensate drain to remove acidic water produced during the process. Non-condensing units are simpler to install (no condensate drain, higher-temp exhaust) but less efficient at 80–85%. Condensing units cost $100–$400 more to buy and $150–$300 more to install, but recover the difference through lower operating costs within 2–4 years.
Gas vs Electric: Full ComparisonConversion Cost BreakdownBrand ComparisonHow to Save on InstallationCost by State