Independent HVAC replacement analysis

Will a new system actually pay for itself?

Contractors quote the price. Utilities quote the rebate. Nobody shows you the whole equation. HVACpayback runs the real numbers — your climate, your rates, your old unit — and shows every assumption on screen, so the repair-or-replace decision is yours — made on complete information.

Calculate cooling savings Calculate heating savings
Free · no sign-up · every source cited

How to decide

1

What does the old unit cost you?

Energy at its degraded efficiency, plus repairs that climb every year. Most people only see the repair bill. How to total it →

2

What would a new one save?

Savings scale with the efficiency ratio — SEER2 for cooling, AFUE or HSPF2 for heat — times how much conditioning your climate demands. Ratings, decoded →

3

What's the net cost?

Quoted price minus utility rebates and state HEAR/HOMES rebates (the federal 25C credit ended Dec 31, 2025). Net cost is often thousands below sticker. Stack the incentives →

4

When does it pay back?

Payback is where cumulative savings overtake net cost. Under ~8 years is usually a clear yes; the calculators find your exact year. Payback, explained →

The calculators

Bills-based or ZIP-based · every assumption editable · print-ready results

Cooling savings

SEER → SEER2

For central AC and heat pumps in cooling mode. Uses your actual utility bills, or your ZIP’s climate hours and average electricity rate. Every assumption is on screen and editable.

$/yr savingsPayback year15-yr savingsKeep-vs-replace curveCO₂ avoided
Open cooling calculator

Heating savings

AFUE · HSPF2

For gas furnaces — and the question of the decade: high-efficiency furnace, or switch to a heat pump? Compares gas and electric operating cost on the same chart using your gas and electricity prices.

$/yr savingsPayback year15-yr savingsFurnace vs. heat pumpBreak-even $/therm
Open heating calculator
More than the money

The benefits that never
show up on a bill

The calculators measure dollars because dollars can be measured. But a year in, most people talk about something else first: the house finally feels right. If your payback is marginal, this is what you're actually buying with the difference.

Read the full comfort guide
Steadier tempsWithin ~1°F all day — variable speed ends the swing-and-blast cycle. Drier summersLonger, gentler cycles pull real moisture — no more clammy 74°F. Quieter roomsMid-50s dB where old units roared at 75+ — inside and out. Cleaner air potentialNew blowers handle MERV 11–13 filters; longer runs filter more. Even, every roomContinuous gentle airflow finally fixes the hot-upstairs problem. Safer heatFresh heat exchanger — or no combustion at all with a heat pump.

Understand before you buy

The terms, the math, and the trade-offs

Check the math yourself

Most "savings calculators" are lead-capture forms with a marketing model behind them. This one is the opposite: an education tool with the model in the open. Every result ships with a "math behind these numbers" panel that recomputes your inputs step by step, and where a judgment call existed, we took the side that understates your savings.

Climate comes from five years of per-ZIP weather reanalysis, electricity rates from NREL/EIA-861 utility data, grid carbon from EPA eGRID — all cited on the methodology page. If you find an error, we want to know.

  • Conservative by designThe keep-vs-replace model assumes your old unit survives all 15 years without a catastrophic failure — generous to keeping it.
  • Every input stays on screenZIP lookups prefill values; nothing is hidden. Edit the rate, the hours, the escalation — the model updates live.
  • No leads, no affiliationsWe don't sell equipment, capture contacts, or take manufacturer money. The recommendation is whatever your numbers say.