Run-Cost & Payback
Calculator

Real climate data, real energy rates, and — if you share your last year's HVAC bill — calibrated to your actual spending.

Step 01

Where is your home?

ZIP Code

We pull your local climate and electricity rate automatically.

Step 02

Your space

Square feet

Whole home, or the single room you're conditioning.

Step 03

Your current heating / cooling

Pick how your home is heated and cooled today. We'll show you which efficiency numbers to enter.

Current system

System type

Furnace AFUE (%)

On the nameplate or manual. Pre-2000 furnaces: ~78–82%. Modern high-efficiency: 90–98%.

Do you also have central AC?

Central AC SEER2

▾

Pre-2023 units report plain SEER — subtract about 1 to approximate SEER2 (e.g., a SEER 16 unit is ~SEER2 15).

Step 04

The new mini-split

Pick the efficiency ratings of the unit you're considering.

New mini-split

SEER2 (cooling)

▾

Typical DIY range: 18–28. Most popular units sell around 22.

HSPF2 (heating)

▾

Typical range: 8–11. Cold-climate units reach 10+.

Step 05

Calibrate with your utility bill — optional

Last 12 months of HVAC spending. When provided, we scale our estimate so it matches your actual spend — the single biggest accuracy boost per NREL ResStock.

Estimated annual HVAC cost ($)

Rough number is fine — skip if unsure. We'll use our model's estimate as a fallback.

1,500 sqft · 1 current system · 1 mini-split