# SEER2 vs. SEER: compare cooling efficiency on the same basis

Canonical: https://www.savpwr.com/knowledge/seer2-vs-seer
Market: United States
Author: SAVPWR Editorial (VDX Logic LLC)
Published: 2026-11-09
Sources checked: 2026-11-09

## Can I compare an old SEER rating directly with a new SEER2 rating?

Not as a precise savings calculation. SEER and SEER2 use different test procedures. Obtain ratings on the same basis for an equivalent matched system before calculating a cooling-electricity scenario. Neither rating measures your household bill.

## What the units mean

SEER2 divides seasonal cooling output in Btu by seasonal electricity input in watt-hours (Wh). One kWh is 1,000 Wh: confusing these changes the meaning by a factor of 1,000. The rating describes tested equipment, not a meter reading from your house. [1]

## Why a universal conversion is a poor decision tool

Appendix M1 testing changed operating conditions relative to the earlier procedure. Do not treat a quick percentage conversion as a verified rating for your installed system. Ask for the old equipment documents and the exact proposed indoor/outdoor combination. An advertised maximum for a product family is insufficient. [1][2]

## Turn the rating into a bounded question

Once comparable ratings are available, separate cooling electricity from the rest of the bill. Hold delivered cooling, weather and usage constant in the scenario. If those conditions change, describe the result as a comparison of assumptions rather than a measured saving.

## Decision exercise

If comparable SEER2 values are 10 and 20, a simplified constant-load model uses 10/20 = 0.50 times the cooling electricity. If cooling was 40% of a 12,000-kWh annual bill, estimated savings are 2,400 kWh, not 6,000 kWh. This is a synthetic example, not a forecast.

Numbers are illustrative assumptions, not forecasts.

## Preparation checklist

- Record whether each document says SEER or SEER2.
- Request the matched-system certificate and model suffixes.
- Keep cooling share and electricity price visible in the calculation.

## Does a higher SEER2 guarantee a smaller bill?

No. Installation, weather, usage, tariffs and other electrical loads can offset the rated-efficiency difference.

## Sources

[1] ENERGY STAR — Heat Pump Equipment Key Product Criteria: https://www.energystar.gov/products/air_source_heat_pumps/key-product-criteria
[2] AHRI — Directory of Certified Product Performance: https://www.ahrinet.org/certification/ahri-directory

AI-assisted preparation; no licensed professional review is claimed. Editorial policy: https://www.savpwr.com/editorial