Research
HVAC demand by climate zone
How heating and cooling equipment changes from the Gulf Coast to the northern border, measured in the homes themselves.
Written by HYRE HVAC Research Desk Primary-source research, data analysis and fact checking
The finding
HVAC demand by climate zone splits the country in two. In the hot zones 1 and 2, homes average 3,912 cooling degree days a year, 94.6% have air conditioning and 26.9% heat with a heat pump.
In zones 5 and 6, gas heats about 66% of homes and heat pumps fall to 4.1% and 2.0%. Air conditioning is near universal everywhere except the coldest zones, where 64.1% of homes have it.
What is an IECC climate zone?
It is the map the energy code uses. The International Energy Conservation Code (IECC) splits the US into zones 1 (hottest) to 8 (coldest), by county.
Many state energy codes use it to set insulation and window rules.
EIA tags every home in its 2020 Residential Energy Consumption Survey with its zone, so we can see what equipment homes in each zone actually use.
We group zones 1 with 2 and 7 with 8, because the extremes hold too few survey homes to stand alone. The labels in brackets (hot, warm, mixed, cool, cold, very cold) are ours, for reading ease.
To look up the degree days for your own area, use our degree day lookup. For how degree days relate to equipment size, see the BTU calculator.
What do homes in each climate zone use?
| Zone | Share of US homes | Heating degree days | Cooling degree days | Any AC | Central AC | Heat pump main heat | Gas main fuel | Electric main fuel |
|---|---|---|---|---|---|---|---|---|
| Zones 1-2 (hot) | 15.5% | 767 | 3,912 | 94.6% (± 0.5) | 85.0% (± 0.9) | 26.9% (± 1.1) | 21.7% (± 0.8) | 59.1% (± 1.1) |
| Zone 3 (warm) | 24.9% | 2,048 | 1,942 | 84.9% (± 0.7) | 70.5% (± 0.7) | 16.8% (± 0.6) | 52.2% (± 0.8) | 37.5% (± 0.8) |
| Zone 4 (mixed) | 25.2% | 4,106 | 1,221 | 88.9% (± 0.5) | 64.7% (± 0.7) | 17.1% (± 0.6) | 49.0% (± 0.8) | 38.7% (± 0.8) |
| Zone 5 (cool) | 26.7% | 5,587 | 938 | 90.4% (± 0.5) | 61.5% (± 0.7) | 4.1% (± 0.3) | 66.2% (± 0.8) | 18.9% (± 0.6) |
| Zone 6 (cold) | 6.8% | 7,210 | 628 | 84.2% (± 1.1) | 52.2% (± 1.2) | 2.0% (± 0.3) | 59.3% (± 1.3) | 14.4% (± 1.0) |
| Zones 7-8 (very cold) | 0.9% | 9,413 | 299 | 64.1% (± 2.6) | 32.4% (± 3.1) | too few respondents | 41.0% (± 3.0) | 19.6% (± 2.4) |
| United States | 100% | 3,729 | 1,693 | 88.7% | 13.9% | 50.8% |
RECS 2020, weighted to all occupied US homes. Degree days are the survey’s base-65°F annual figures for each home, averaged across homes. Standard errors in brackets.
Where do heat pumps beat gas furnaces in the market?
Only in the hottest zones, and only barely. In zones 1-2, 26.9% of homes heat with a heat pump and 21.7% with gas. Zone 3 is already a gas majority at 52.2%, with heat pumps at 16.8%.
From zone 5 north the market is a gas market. Zone 5 heats 66.2% of homes with gas and 4.1% with a heat pump; zone 6 is 59.3% and 2.0%. Zones 7-8 rely more on other fuels, with gas at 41.0% and propane or fuel oil at 31.1%.
HyreHVAC analysis: the zone line is close to a price line. Cold zones tend to have cheap gas and dear electricity, which is the subject of our electric vs gas price ratio study. How new cold-climate heat pumps perform at 5°F is covered in a separate study.
Does cooling demand follow the climate zones?
Mostly, but AC ownership is high almost everywhere. Homes in zones 1-2 average 3,912 cooling degree days a year, against 299 in zones 7-8: about 13 times as much. Yet AC ownership is 84.2% in zone 6 and 90.4% in zone 5, close to the hot zones.
Central AC tracks the climate more closely than AC ownership does. It is 85.0% in zones 1-2, 64.7% in zone 4 and 32.4% in zones 7-8. Window and portable units fill the gap in cooler places: 28.7% of homes in zones 7-8 cool mainly with one.
The coldest zones keep their air conditioners longest. 24.2% of air conditioners in zones 7-8 are 15 years or older, against 14.4% in zones 1-2. The survey cannot say why; light use is one plausible reason. Our equipment lifespan study looks at age in more depth.
How do equipment type and age differ by zone?
| Zone | Central furnace | Boiler (steam or hot water) | Ductless heat pump | Propane or oil | Ducted home | AC 15+ years old | Heating 15+ years old |
|---|---|---|---|---|---|---|---|
| Zones 1-2 (hot) | 44.8% (± 1.2) | too few respondents | 1.0% (± 0.2) | 0.9% (± 0.2) | 90.4% (± 0.7) | 14.4% (± 0.8) | 19.8% (± 1.1) |
| Zone 3 (warm) | 60.8% (± 0.8) | 0.8% (± 0.2) | 0.8% (± 0.2) | 3.2% (± 0.3) | 84.3% (± 0.7) | 19.5% (± 0.8) | 30.5% (± 0.9) |
| Zone 4 (mixed) | 55.0% (± 0.8) | 11.7% (± 0.5) | 1.3% (± 0.2) | 8.8% (± 0.5) | 78.2% (± 0.7) | 19.6% (± 0.7) | 33.5% (± 0.8) |
| Zone 5 (cool) | 71.6% (± 0.7) | 12.0% (± 0.5) | 0.4% (± 0.1) | 12.2% (± 0.5) | 81.0% (± 0.5) | 22.2% (± 0.7) | 37.4% (± 0.7) |
| Zone 6 (cold) | 69.5% (± 1.5) | 14.1% (± 1.1) | 0.6% (± 0.2) | 21.9% (± 0.9) | 75.0% (± 1.4) | 23.3% (± 1.3) | 39.2% (± 1.2) |
| Zones 7-8 (very cold) | 53.1% (± 2.8) | 22.2% (± 2.6) | too few respondents | 31.1% (± 3.1) | 60.1% (± 3.0) | 24.2% (± 4.9) | 34.7% (± 3.6) |
RECS 2020. Equipment shares are of all homes in the zone; age shares are of homes with that equipment.
A cell reading "too few respondents" has a relative standard error above 30%, the level at which EIA itself stops publishing.
How did we calculate these figures?
The EIA RECS 2020 public use file, version 7, downloaded on October 26, 2026. 18,496 homes, weighted to 123.53 million occupied homes.
The file’s IECC_climate_code variable, which EIA supplies for each home. We grouped 1A, 2A and 2B as zones 1-2, and 7A, 7B, 7AK and 8AK as zones 7-8. Moisture letters (A, B, C) are merged within each number.
Heat pump means the main heating equipment is a central or ductless heat pump. Central AC counts central equipment as main or secondary cooling, matching EIA’s own tables. Ducted means a furnace, central heat pump or central AC.
Each home’s annual heating and cooling degree days (base 65°F) as supplied in the file, averaged with survey weights.
Standard errors use the 60 replicate weights, as in all our RECS studies. Cells with a relative standard error above 30% are not shown.
What does this data leave out?
Installations since 2020 are not reflected. The next RECS cycle will update every figure here.
A home with AC that runs it ten days a year counts the same as one that runs it all summer. Degree days give the climate load, not the actual run hours.
Zone 4 alone includes humid, dry and marine areas (4A, 4B and 4C). A zone figure is an average across very different places, so read it as a pattern, not a forecast for one home.
How should you cite this study?
Please cite it as: HyreHVAC Research Desk, “HVAC demand by climate zone,” hyrehvac.com/research/hvac-demand-by-climate-zone/, from EIA RECS 2020 microdata retrieved October 26, 2026. Charts may be reused with that credit and a link. The CSV below holds every cell with its standard error.
Questions
Which climate zone has the most heat pumps?
Do homes in cold climates have air conditioning?
What climate zone am I in?
What is a cooling degree day?
Is this data current?
Written and audited by
HYRE HVAC Research Desk
Primary-source research, data analysis and fact checking
We are a research desk, not a sales floor. We read the federal microdata file, the statute or the manufacturer data sheet ourselves, and we publish the figure with the document it came from and the date we retrieved it.
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Data as of EIA RECS 2020 microdata v7, retrieved October 26, 2026. Authorship on this site is organizational: the analysis belongs to the desk rather than to a named individual, and we do not publish credentials we do not hold. Our editorial policy sets out how we source, date and correct what we publish.
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Every figure on this page is computed from one file, and that file is published here so the analysis can be checked, disagreed with, or reused.
Sources & retrieval dates
Size by load, not by zone
A zone is a starting point. Equipment should be sized to your own home’s load, which the calculators estimate from your square footage and climate.