The fastest ways to lower indoor temperature without air conditioning
If your apartment has air conditioning, the most direct approach is to use it efficiently: close interior doors to rooms you are not occupying, set the thermostat to 78°F during the day and higher when you are away, and run the unit during cooler morning and evening hours rather than the hottest part of the afternoon. If you do not have air conditioning or want to reduce how much you run it, blocking sunlight and moving air are your two main tools.
Blocking heat before it enters the apartment works faster than trying to cool the air after. Close blinds, curtains, or shades on windows that face the sun during the day—especially south and west-facing windows in the afternoon. Blackout curtains or thermal-lined curtains are more effective than thin fabric, but even regular curtains reduce heat gain. Reflective window film or temporary exterior shading (like cardboard or plywood over a window frame) blocks even more heat, though it looks temporary because it is.
Moving air creates the feeling of cooling even when the actual temperature does not drop. A box fan in a window pulling outside air in, combined with a fan on the opposite side of the apartment pushing warm air out, creates cross-ventilation. Ceiling fans and portable fans circulate air within the room. Fans use far less electricity than air conditioning and work best during cooler parts of the day—early morning, evening, and night.
Key Takeaways
- Close blinds and curtains on sun-facing windows during the day, especially in the afternoon, to stop heat from entering before you have to cool it.
- Use fans to move air across the apartment during cooler hours (morning, evening, night) rather than running air conditioning all day.
- If you have air conditioning, close doors to unused rooms and raise the thermostat when you are away to reduce energy use.
- Avoid using heat-generating appliances like ovens during the hottest part of the day; use the microwave, stovetop, or eat cold meals instead.
- Check your lease or contact your landlord before installing window units or making permanent changes to windows or walls.
Reducing heat from appliances and lighting
Ovens, stoves, and other heat-producing appliances add significant warmth to an apartment. During summer, use the microwave, toaster oven, or stovetop instead of a full oven. Eat cold meals—salads, sandwiches, no-cook pasta, fruit—when possible. If you must cook, do it in the early morning or after sunset when outdoor temperatures are lower and you can open windows without pulling in hot air.
Incandescent and halogen light bulbs generate heat as a byproduct of light. Switching to LED bulbs reduces both heat and electricity use. Use only the lights you need, and turn them off when you leave a room. During the day, rely on natural light from windows rather than turning on overhead lights.
Refrigerators and freezers work harder in hot apartments and generate heat as they cool. Keep the coils clean (usually on the back or bottom of the unit), do not block vents with food or items, and avoid opening the door repeatedly. If you have a second refrigerator or freezer you do not actively need, unplugging it during summer removes a constant heat source.
Using water and humidity to cool your space
Evaporative cooling works in dry climates: wet a sheet or towel, hang it in front of a fan or open window, and the air passing through it cools slightly as the water evaporates. This is less effective in humid climates where the air already holds moisture, but it still provides some relief. You can also place a bowl of ice in front of a fan to cool the air passing through it, though this is a temporary measure.
Taking cool showers or baths before bed lowers your core body temperature and helps you sleep better in heat. Wearing light, loose-fitting clothing made from cotton or linen allows sweat to evaporate and keeps you cooler than tight synthetic fabrics. Sleeping with damp sheets or a damp pillowcase also helps, though it can feel uncomfortable if humidity is high.
Avoid using a humidifier or running a dishwasher or washing machine during the hottest part of the day, as these add moisture and heat to the apartment. If you do laundry, do it early morning or evening, and hang clothes to dry rather than using a dryer.
Managing windows and ventilation
Open windows during cooler hours—typically early morning, evening, and night—and close them before the temperature outside rises above the indoor temperature. In many climates, the outdoor temperature drops significantly after sunset, making nighttime the best time to ventilate. Open windows on opposite sides of the apartment to create cross-ventilation, which moves air through the space more effectively than opening a single window.
If you have a basement or lower-level apartment, it will naturally stay cooler than upper floors because heat rises. If you live on an upper floor, this cooling strategy is less effective, but opening windows at night and closing them during the day still helps.
Check your lease before installing a window air conditioning unit. Many leases require landlord permission, and some buildings do not allow them for structural or aesthetic reasons. If you want to install a unit, get written permission from your landlord first. Portable air conditioners that vent through a window are an alternative if window units are not permitted, though they are less efficient and more expensive to run.
What to do if your apartment stays hot despite these steps
If your apartment remains uncomfortably hot even after closing blinds, using fans, and opening windows at night, the building itself may have poor insulation, inadequate ventilation, or a malfunctioning HVAC system. Document the temperature inside your apartment with a thermometer and take photos or video showing the conditions. Write to your landlord describing the problem, the steps you have taken, and the indoor temperature you are measuring. Keep a copy of this communication.
In many jurisdictions, landlords are required to maintain habitable conditions, which includes keeping apartments within a reasonable temperature range during summer. If your landlord does not respond or refuses to address the problem, contact your local housing authority or tenant rights organization to learn what remedies are available in your area. Some places allow tenants to withhold rent, pay for repairs and deduct the cost from rent, or break a lease if the apartment becomes uninhabitable due to heat.
In the meantime, spending time in public spaces with air conditioning—libraries, community centers, shopping malls, coffee shops—during the hottest part of the day is a practical way to get relief without paying for cooling your apartment.
Frequently Asked Questions
Does leaving a fan on when I am not home help cool the apartment?
No. A fan cools people by moving air across their skin, not by lowering the actual temperature. If no one is in the apartment, a running fan only wastes electricity. Turn fans off when you leave. However, if you have windows open and a fan positioned to pull cooler outside air in and push warm air out, it can help during cooler hours even if you are not there.
Should I close my apartment door to keep cool air in one room?
Closing doors to unused rooms does reduce the space you need to cool, which saves energy if you are using air conditioning. However, it can trap heat in closed rooms and reduce air circulation. If you are using fans and ventilation, keeping doors open usually works better because it allows air to move freely through the apartment.
Is it cheaper to run air conditioning all day or to turn it on and off?
Turning air conditioning off when you are away or during cooler hours is cheaper than running it continuously. Modern air conditioners do not use extra energy to restart, so turning the unit off during the coolest parts of the day and back on when you need it reduces overall electricity use and cost.
Can I use my oven if I cover it with a wet towel?
No. Covering an oven with a wet towel is a fire hazard and does not prevent heat from escaping into the apartment. Use a microwave, toaster oven, or stovetop instead, or cook during cooler hours when you can open windows to vent the heat outside.
What temperature should I set my thermostat to in summer?
The U.S. Department of Energy suggests 78°F when you are home and awake, and higher (80–85°F) when you are away or sleeping. Every degree you raise the thermostat saves roughly 1–3% on cooling costs. Set it as high as you can tolerate, use fans to stay comfortable, and lower it only during the hottest part of the day if necessary.