Before you call a local installer — what a fair tankless quote looks like
Searching "installation near me" usually means you're ready to book someone — so the useful thing isn't another list, it's knowing what a fair quote looks like before the truck shows up. A straightforward gas tankless replacement (like-for-like fuel, existing gas line adequate) typically runs $1,500–$2,500 installed; add $500–$1,500 if the gas line needs upsizing or the venting must change. Electric installs hinge on your panel — a simple swap is cheaper, but a needed service/panel upgrade can add $1,000–$3,000. Questions worth asking any local installer: Is the unit condensing (cheaper venting)? Does my gas line / panel need upsizing? Is the quote permit-and-inspection inclusive? What's the labor warranty on top of the manufacturer's heat-exchanger warranty? Get 2–3 quotes — tankless install pricing varies widely by region and by how comfortable the installer is with tankless specifically. The tool below helps you walk in knowing the best-value unit to request; every slider is yours. For line-item costs, see our installation cost calculator.
What about installation cost?
Sticker price is only half the story — condensing units need special venting, electric units may need a panel upgrade. The tool ranks on unit value; use the fuel filter to compare within an install type (all-gas vs all-electric) so you're not comparing a cheap electric against a gas unit that costs $1,500 to vent. (A dedicated installation-cost calculator — the highest-demand tankless search — is live.)
Condensing vs non-condensing: the choice that drives both your bill and your install
This is the first real fork. A non-condensing unit (e.g. the Rinnai V75iN, ~0.81 UEF) is cheaper up front (~$780) but vents hot exhaust through expensive stainless-steel or Category III venting and wastes more heat. A condensing unit (Navien NPE, Rinnai RX, Rheem Prestige — 0.93–0.98 UEF) captures a second pass of heat from the exhaust, running cool enough to vent through cheap PVC and cutting gas use meaningfully. Rule of thumb: condensing costs $300–600 more for the unit but is usually cheaper to vent and pays back the difference in gas savings within a few years — especially if you run a lot of hot water. The tool's UEF axis is where this shows up; sort by it to see the efficiency spread directly.
Gas vs electric tankless: which one fits your house
The honest limiter on electric tankless isn't efficiency — electric units hit ~0.99 UEF — it's flow in cold climates and your electrical panel. The best electric units here (Stiebel Eltron Tempra 29, Rheem RTEX-27) top out around 2.9–3.1 GPM at a 70° rise and can demand 100+ amps of dedicated service, often forcing a panel upgrade. That's fine for a warm climate, a point-of-use application, or a small household — and electric wins on up-front price ($430–850) and needs no venting at all. Gas (natural gas or propane) is what a cold-climate whole-house family wants: 4.5–5.7 GPM at rise, no panel upgrade, but it needs a gas line and venting. Use the fuel filter above to compare like-for-like instead of pricing a $430 electric against a $1,500 gas unit that solves a different problem.
Why we don't just name a winner
"Best tankless" depends entirely on your fuel, climate and household size. A cold-climate family cares about flow; a bill-watcher cares about UEF; a landlord cares about warranty. One name buries that — the Value Score keeps it in your hands, formula in the open right above. (Sizing for a specific household? See our tankless sizing for a family of 4 walkthrough.)
The specs, briefly
UEF = efficiency, how much energy reaches the water (higher = lower bills). Flow @ 70° rise = real cold-weather simultaneous-shower capacity. HX warranty = years on the heat exchanger, the part that fails. Recirculation = instant hot water at the tap (built-in pump only — "recirc-capable" without a factory pump doesn't count here). Min-flow = how little flow fires it (low = no cold-water sandwich).
Specs verified Aug 2026 against manufacturer spec sheets + ENERGY STAR product finder. Prices are approximate street prices (unit only, not installed) pending live-retailer verification. Some links may be affiliate; that never changes the Value Score — the math runs on published specs, not payouts.