How to Lower Your Summer Cooling Costs

Editorial review as of September 3, 2026. Sources cited in the article were verified against their linked origin, and the figures below were re-checked on this date.

In warm climates, summer cooling can be the single largest seasonal expense in a household budget. Air conditioning is energy-intensive, and the higher outdoor temperatures get, the harder the system works. The good news is that cooling costs are highly responsive to small changes, and most households can reduce them by 20 to 35 percent without making the home noticeably warmer.

The framework below covers the highest-impact changes in roughly the order they tend to produce results.

The thermostat is doing most of the work

Each degree higher on your cooling thermostat reduces cooling costs by 2 to 4 percent for the season. The math compounds quickly. Raising the setting from 72 to 78 degrees during the day typically reduces cooling costs by 15 to 25 percent.

Practical settings:

• 78 degrees when home and active
• 82 to 85 degrees when away (or off entirely for short absences)
• 74 to 76 degrees overnight if you find that cooler temperatures support sleep

A programmable or smart thermostat handles the schedule automatically. The 78-degree daytime setting feels warm at first to households used to 72 degrees, but most acclimate within a few weeks.

Ceiling fans extend comfort range

Ceiling fans do not actually cool the air, but they create a wind-chill effect that makes 78 degrees feel like 75 degrees. The fans use far less electricity than the AC.

The combination of higher thermostat setting plus ceiling fans typically produces comfort equivalent to a lower thermostat setting without fans, at significantly lower energy cost.

Turn ceiling fans off when leaving a room. Fans cool people, not rooms. Leaving them running in empty rooms wastes electricity without producing benefit.

For homes without ceiling fans, portable fans work similarly. A box fan or oscillating fan in the room you are using is much cheaper to run than dropping the AC by several degrees.

Manage solar gain through windows

Direct sunlight through windows can raise indoor temperatures noticeably, especially in homes with east, west, or south-facing windows. Managing solar gain is one of the highest-return cooling interventions.

The methods:

• Close blinds or curtains during the hottest part of the day on sunny-facing windows
• Use reflective window film on the worst windows
• Install exterior shading (awnings, shade sails, trees) where practical
• Use thermal-lined curtains, which work in summer as well as winter

For homes with large unshaded windows facing the afternoon sun, these changes can reduce cooling costs by 10 to 20 percent during the hottest months.

Address attic heat

Attic temperatures in summer can exceed 130 degrees Fahrenheit, even when outdoor temperatures are 90 degrees. The hot attic heats the ceiling of the living space below, increasing the cooling load.

The interventions:

• Make sure attic insulation is adequate (the same insulation that helps in winter helps in summer)
• Ensure attic ventilation is working (ridge vents, soffit vents, gable vents)
• Consider an attic fan for very hot climates
• Reflective roof coating on older roofs (more involved, but high-impact)

For under-insulated homes in hot climates, attic insulation is often the single highest-value cooling investment. Payback periods are typically three to seven years through cooling savings alone.

Maintain the AC system

An efficient AC system uses 10 to 25 percent less energy than a poorly maintained one. The maintenance is straightforward:

• Replace the air filter monthly during cooling season
• Have the system serviced annually (clean coils, check refrigerant, inspect components)
• Keep the outdoor condenser unit clear of debris and vegetation
• Make sure indoor vents are unblocked and clean

The annual professional service costs $75 to $200 and typically pays for itself in efficiency improvements. For older systems (over 10 years), the service also catches developing problems before they become summer emergencies.

Reduce indoor heat sources

Several activities add heat to the home, which the AC then has to remove. Reducing or timing these activities can lower cooling load.

The biggest indoor heat sources:

• Oven and stove (cook with small appliances, outside grill, or in cooler hours when possible)
• Clothes dryer (dry full loads, use cool cycles, line-dry when possible)
• Dishwasher heated drying (turn off and let dishes air-dry)
• Hot showers (use exhaust fan and shorter showers in summer)
• Older incandescent bulbs (replace with LED, which produce far less heat)
• Computers and TVs (use sleep modes and turn off when not in use)

None of these are major savings individually. Together, they can reduce cooling demand by 5 to 15 percent in summer.

Open windows when outdoor air is cooler

In many climates, overnight temperatures drop significantly below daytime peaks. Opening windows in the evening and closing them before the heat returns can pre-cool the home without using AC.

The pattern: open windows when outdoor temperature drops below indoor temperature (usually evening to early morning). Close windows and blinds in the morning before outdoor temperatures rise. Run the AC as needed during the day.

This approach is most effective in climates with significant day-night temperature variation. In humid climates, opening windows brings in humidity that the AC must then remove, which can negate the savings.

Zone cooling for unused rooms

Like winter heating, cooling can be zoned to focus on rooms you are actively using. Closing doors and partially closing vents in unused rooms reduces the overall cooling load.

For multi-zone systems with multiple thermostats, this is straightforward. Set unused zones to 84 or 86 degrees and active zones to 78.

For single-thermostat homes, closing doors and partially closing vents in unused rooms achieves a similar effect at the cost of some uneven cooling. The home may feel less consistently cool, but the AC runs less.

Consider larger investments for hot climates

For homeowners in hot climates planning to stay long-term, several larger investments produce meaningful cooling savings:

• Upgraded AC system (especially replacing systems over 15 years old)
• Whole-house attic fan
• Reflective roof or cool roof coating
• Window replacement (especially for old single-pane windows)
• Tree planting for shade (long-term benefit, but real)

These investments are not for every household, but in hot climates they can produce substantial long-term savings.

The honest summary

Summer cooling costs are highly responsive to small changes. The combination of higher thermostat settings, ceiling fans, window management, and basic system maintenance typically reduces cooling costs by 20 to 35 percent. The investments are minimal, the disruption to comfort is small (especially with ceiling fans), and the savings repeat every summer.

For pairings, see our pieces on winter heating and reading electricity bills.