NOAA 1991-2020 Climate Normals
AC & Heating Cost Factors for Indianapolis, IN
Real climate and electricity-rate data for Indianapolis, IN — the inputs that actually drive your cooling and heating costs, not a generic national estimate.
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Cooling degree-days
Summed across the year, not a day count
5,776
Heating degree-days
Summed across the year, not a day count
10
Days ≥ 90°F
Per year, average
17.9¢
Electricity rate
IN residential, 2026-04
What this means if you live in Indianapolis: your cooling load is the lowest of the 20 cities we track — about 57% below the average across the metros we track. In practice, that means your AC isn't just running on the hottest afternoons — in a city this hot, it's cycling on and off for a large share of the year, so total runtime hours (not just peak temperature) are what drive your bill up. Heating demand here is the opposite story — the highest of the 20 cities we track, about 84% above the average. Heating still accounts for a meaningful share of your annual HVAC cost here. That imbalance is exactly why a system sized and rated for Indianapolis, IN's specific climate — not a generic national spec — matters more here than in a milder city: an undersized or lower-efficiency AC unit gets exposed fast under this much cumulative runtime, and a contractor unfamiliar with how extreme the local cooling season is can easily under-spec the job.
What's a "degree-day," exactly?
It's not a count of days — it's a cumulative unit. Every day, take how many degrees the average temperature sat above 65°F, then add that number up across all 365 days of the year. A 95°F day contributes 30 (95 − 65); a mild 68°F day contributes just 3. Add that arithmetic up across a full year and you get a number much bigger than 365 — it's tracking total heat load over time, not elapsed days. It's the actual measure HVAC engineers and utilities use to size systems and predict bills, because it captures both how hot it gets and how long it stays hot, which a single "average temperature" figure can't separate.
Degree-day and extreme-temperature data: NOAA National Centers for Environmental Information, 1991-2020 U.S. Climate Normals, station GHCND:USC00124272. Electricity rate: U.S. Energy Information Administration, state-level residential average. Comparison figures are computed across the 20 metros ClearPick currently tracks, not a national survey. An exact annual dollar cost depends on your home's size, insulation, and system efficiency — get a contractor quote for a number specific to your house.
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