Table of Contents
Tankless Cost by Type (2026)
| Type | Unit cost | Installed total |
|---|---|---|
| Electric, whole-house | $500–$1,200 | $1,500–$3,500 |
| Gas (natural gas), whole-house | $800–$2,000 | $3,000–$5,500 |
| Gas (propane), whole-house | $900–$2,200 | $3,200–$5,800 |
| Electric, point-of-use (single fixture) | $100–$400 | $250–$900 |
Ranges from published 2026 guides (HomeAdvisor avg $2,638; Home Depot $2,400–$5,400; BuildCost national data).
Your Install Scenario Matters More Than the Unit Price
| Scenario | Typical cost | What’s involved |
|---|---|---|
| Direct swap (tankless → tankless, same fuel/location) | $1,200–$2,800 | Reuse gas line, venting, mounting |
| Tank-to-tankless conversion, same fuel | $2,000–$4,500 | New venting, gas line sizing check, condensate routing, tank removal |
| Full conversion (fuel change / panel work) | $2,500–$7,000+ | New gas piping, rerouted vent, or electrical service upgrade |
The unit is only 30–50% of the total. Labor, venting, gas/electrical upgrades, permits, and old-tank disposal make up the rest.
The Hidden Costs Nobody Mentions Upfront
- Gas line upsizing: $500–$1,000 (tankless units need much more gas flow than tank heaters)
- Venting: $300–$600+ (stainless steel concentric vent; can’t reuse old B-vent)
- Electrical: electric whole-house units often need 3–4 dedicated 40–60A breakers — a panel upgrade ($1,500–$4,000) if you’re out of space
- Water treatment: hard water kills tankless units; a softener/conditioner ($500–$2,000) is near-mandatory in hard-water areas
- Annual descaling: $150–$250/yr maintenance (skipping it voids most warranties)
Does Tankless Actually Pay Back?
A gas tankless saves roughly $150–$300/year in energy vs. a standard tank. The install premium over a tank replacement ($1,200–$2,500 installed) is typically $1,500–$3,000.
Payback: 7–15 years on energy alone — roughly the unit’s lifespan. The honest reasons to go tankless: endless hot water, 20+ year lifespan (vs. 10–12 for tanks), and space savings — not energy payback. If payback is your only goal, a heat pump water heater (where rebates exist) pencils better.
Tank vs. Tankless: 2026 Snapshot
| Tank (50-gal gas) | Tankless (gas) | |
|---|---|---|
| Installed | $1,200–$2,500 | $2,500–$5,500 |
| Lifespan | 10–12 yrs | 20+ yrs |
| Energy savings | Baseline | $150–$300/yr |
| Hot water | Runs out | Endless |
| Maintenance | Minimal | Annual descaling required |
5 Ways to Save
- Same fuel, same location — every change of fuel or spot adds $500–$2,000.
- Bundle with other plumbing work — one permit, one visit.
- Get 3 quotes specifying the scenario — “conversion” vs. “swap” quotes aren’t comparable.
- Check utility rebates — gas utilities still rebate high-efficiency tankless in many states.
- Size it right — GPM rating must cover simultaneous uses (shower + dishwasher); undersizing is the #1 regret.
Sources & methodology
Ranges from HomeAdvisor (June 2026), Home Depot installation guide, BuildCost, Fixr (Jan 2026), Eccotemp (Aug 2026). Planning figures, not quotes.
Disclaimer: 2026 US national averages. Gas/plumbing work involves safety — use licensed pros. Get 3 written local quotes.