The long-term trend

Your summers are getting hotter.
Your bills are following.

Cooling demand has risen across nearly every US state for two decades. Here's what the data actually shows - including one counterintuitive twist for solar panel owners.

45 of 48States with rising cooling demand since 2000s
+71%Projected household cooling demand increase by 2050
-0.3 to -0.5%Solar efficiency lost per °C above 77°F
The data

This isn't a forecast -
it's already happening.

An analysis of 25 years of federal NOAA climate data found that cooling degree days - a standard measure of how much air conditioning demand rises with heat - have increased in 45 of 48 contiguous states since the early 2000s.

A separate Climate Central analysis found annual cooling degree days have increased since 1970 in 232 of 240 US locations studied - covering 97% of the areas examined.

Projection: cooling demand to 2050

According to the EIA's latest outlook, projected changes in cooling degree days are expected to drive a 71% increase in household cooling demand by 2050. Commercial buildings are projected to see a 30% increase over the same period.

These are demand projections - how much MORE electricity homes will need for cooling - not predictions about your specific utility rate.

Where it matters most

The South is absorbing
the biggest increases.

The largest cooling cost increases are concentrated in the South, where high temperatures, widespread air conditioning use, and greater exposure to peak electricity demand combine to drive both higher consumption and higher marginal costs.

In contrast, the Midwest's East North Central and West North Central regions are projected to see more modest increases - approximately 4.8% for summer 2026, around $30 per household.

South
Largest absolute increases - highest baseline AC use, highest peak demand exposure.
Midwest
More modest increases - ~4.8% summer cost rise, ~$30/household (2026).
West / Pacific
More variable - can decrease in years with cooler temperatures than the prior year, since baseline usage is more weather-dependent.
Northeast
Historically lower summer electricity use - fewer households rely on AC as heavily as the South.

For perspective: in summer 2025, US households paid an average monthly electricity bill of $178, slightly up from $173 the year before. Weather remains the biggest source of uncertainty in these forecasts - hotter-than-expected summers mean higher-than-expected bills, especially in southern states.

Check your region's rate →
The counterintuitive part

Hotter weather doesn't
mean more solar power.
It can mean less.

This surprises a lot of people: solar panels actually get LESS efficient as they get hotter - not more, even though they need sunlight to work.

The temperature coefficient

Solar panels are tested for efficiency at 25°C (77°F). Most panels have a temperature coefficient between -0.3% and -0.5% per °C above that. For every degree Celsius hotter than 77°F, output drops by roughly that percentage.

On a hot summer day, panel surface temperatures can reach 60°C (140°F) or higher - which can mean a 10-15% decrease in power output compared to the panel's rated efficiency.

Depending on the installation location, heat can reduce solar output efficiency by 10-25% overall.

Why this happens

Heat increases electrical resistance within the solar cells, which reduces the cell's voltage output and, in turn, its overall power production.

Practical implication

This is one reason a balcony solar panel's REAL summer output can run below its rated wattage - even on a cloudless day. Sol Country's savings estimates already account for typical real-world conditions, not just rated laboratory output.

Mitigation

Proper ventilation behind a panel can meaningfully help - increasing the air gap from 2cm to 20cm can reduce panel temperature by up to 10°C. This is part of why mounting position actually matters for real-world output, not just legal placement.

Mounting guidance →
Putting it together

Two trends, one direction:
cooling costs more,
not less.

Here's the honest summary: rising temperatures mean you'll likely use more electricity to stay cool over time (well-documented), while solar panels generate somewhat less per watt of rated capacity on the hottest days (also well-documented). Neither of these facts changes what Sol Country already calculates for you - our savings estimates use NLR's real solar production data, which already factors in regional temperature and weather patterns, not idealized lab conditions.

What we're not claiming

This page does not say climate change is causing any specific utility rate increase. Rate increases have many causes - grid investment, fuel costs, and regulatory decisions among them. What's well-documented is rising COOLING DEMAND (how much electricity you use to stay comfortable) - a separate question from why your specific rate per kWh has changed. See our coverage of electricity rate increases for that separate question.

Practical steps

Three things that help,
regardless of the weather.

Smart thermostat
Automates cooling schedules and reduces waste during peak heat hours. Most renters save $150-300/yr.
Smart thermostats →
Generate your own power
Even with reduced summer efficiency, balcony solar still offsets real cooling costs - and panels perform BETTER in spring and fall when temperatures are milder.
See balcony kits →
Well-ventilated installation
If you do install solar, proper airflow behind the panel meaningfully improves real summer output.
Read the guide →
Sources
NOAA National Centers for Environmental Information2025. Cooling degree day analysis across 48 contiguous US states, ~25-year trend.
Climate Central — States of Change: Cooling Demand2024. Cooling degree days rising in 232 of 240 US locations since 1970.
US Energy Information Administration (EIA) Annual Energy Outlook2025. +71% household cooling demand and +30% commercial cooling demand projected by 2050.
NEADA Summer Cooling Outlook2025. Average US household summer electricity bill of $178; ~$30 / +4.8% projected increase in Midwest for summer 2026.
Shipley Energy — Regional Cooling Cost Analysis2025. South absorbs largest absolute cooling cost increases; West/Pacific year-over-year variability.
Solar.com — How heat affects solar panel output2024. Temperature coefficient range of -0.3% to -0.5% per °C above 25°C (77°F).
Greentech Renewables — Real-world solar panel temperature2024. Panel surface temperatures of 60°C+ on hot days; 10-15% output drop vs rated efficiency.
NREL — Photovoltaic module temperature studies2023. Heat raises electrical resistance and lowers voltage output in silicon cells; ventilation gap from 2cm to 20cm can reduce panel temperature by up to 10°C.

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Sourced · NOAA + EIA data
No false precision
Honest about what's uncertain