Tankless Water Heater Cost Calculator

A tankless water heater costs $1,000–$4,500 installed for most homes. Gas tankless units cost $1,000–$2,000 for the unit plus $800–$1,500 for installation. Electric tankless units cost $500–$1,000 plus $500–$1,000 for installation. Condensing gas models (highest efficiency) run $1,500–$2,500 plus $1,000–$2,000 installation. Add $200–$800 for venting, $300–$800 for gas line upgrades, and $200–$500 for a recirculation pump.

Tankless water heaters cost more upfront ($1,000–$4,500 installed vs $600–$2,300 for tank) but save $100–$150/year on energy bills. Tankless units last 20+ years vs 10–12 for tank heaters. Tankless provides unlimited hot water on demand, while tanks can run out (40–80 gallon capacity). Tankless takes up less space (wall-mounted vs floor unit). Tank heaters are simpler and cheaper to install. Tankless makes financial sense if you plan to stay 7+ years.

Size tankless heaters by flow rate (GPM). Point-of-use (2–4 GPM, $400–$800) serves one sink or shower. Whole-home medium (6–8 GPM, $800–$1,500) handles 2–3 bathrooms simultaneously. High-demand (8–10 GPM, $1,200–$2,000) serves 3+ bathrooms or high-usage homes. Calculate needed GPM: shower = 2.5 GPM, dishwasher = 1.5 GPM, faucet = 1 GPM. Add simultaneous fixtures to determine your peak demand.

Gas tankless heaters ($1,000–$2,000) deliver higher flow rates (6–10 GPM), ideal for whole-home use in cold climates. They require venting ($200–$800) and a gas line. Electric tankless heaters ($500–$1,000) are cheaper, require no venting, and work well for point-of-use or moderate climates. However, electric models may need a 200-amp panel and dedicated circuits. Condensing gas models ($1,500–$2,500) offer 95%+ efficiency with PVC venting (cheaper than stainless steel).

Labor for tankless water heater installation runs $500–$2,000 depending on complexity. Basic installation (replacing existing tankless or simple swap) costs $500–$1,000. Converting from tank to tankless costs $1,000–$2,000 due to new venting, gas line resizing, or electrical upgrades. Venting installation adds $200–$800 (stainless steel for non-condensing, PVC for condensing). Gas line upgrade adds $300–$800 if existing line is too small.

Annual maintenance costs $100–$200 and extends unit life to 20+ years. Descaling/flushing with vinegar ($10 DIY or $150 professional) removes mineral buildup — essential in hard water areas. Clean inlet filter screen every 6 months ($0 DIY). Check venting annually for blockages. Hard water areas (over 11 grains) should flush every 6 months or install a water softener ($500–$2,000). Most manufacturers require annual maintenance for warranty coverage.

Tankless water heaters last 20–25 years with proper maintenance, nearly double the 10–12 year lifespan of tank water heaters. Gas models average 20 years, electric models 20–25 years. Heat exchangers (most expensive component) are warrantied 10–15 years. Factors that reduce lifespan: hard water (descale regularly), oversized units running at low flow, and skipped maintenance. Replacement parts are available for most brands for 15+ years after purchase.

A recirculation pump ($200–$500 installed) circulates hot water through your pipes so you get instant hot water at fixtures without waiting. Without it, tankless heaters have a 10–30 second delay while cold water in the pipes is displaced. Recirculation pumps use $15–$30/year in electricity. Timer-based or demand-activated models reduce energy waste. Worth it if your fixtures are far from the heater (over 40 feet of piping) or if you value instant hot water.