How to Keep Your House Cool Without AC

Air conditioners provide instant, chilling relief on hot days and let you sleep peacefully through the night. But they also drive up your electric bill and tax the power grid. With air conditioners' high cost and many environmental downsides, this is an appliance that many homeowners choose not to run.

Fortunately, there are ways to cool a house without AC. Most methods are easy and inexpensive to implement, while a few long-term solutions require greater time and cost. Either way, with this guide you'll find out how to keep your house cool and pull the plug on your air conditioner (or help you stay cool if you don't have one).

Change Ceiling Fan Rotation

During winter, ceiling fan blades should rotate clockwise to better distribute trapped warm air near the ceiling. But during summer, switch the fan blade rotation to counter-clockwise to create a downdraft which is felt as that direct, cooling breeze. You'll find the switch on the side of the fan motor or on the remote control.

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Open Windows at Night

The coolest time in the 24-hour cycle is typically just before sunrise in most regions —between 4:00 and 7:00 am. Take advantage of all of this free cool air by opening every available window at night. This eliminates the hot air that built up in the house during the day.

Open Skylights

While some skylights are fixed in place and inoperable, many others open up. Be sure to open up your skylights at night. 

Close Windows During the Day

It's fine to leave the windows open during the early part of the morning. Eventually, you will want to close the windows to block heat from entering the home.

Close Blinds During Day

Block direct sunlight and all manner of natural light from entering your home by drawing the blinds shut during the day.

Apply Window-Insulating Film

Modern windows typically have low-E coating embedded in the glass to block ultraviolet rays (UV) from reaching the home's interior. Add another layer of UV blockage by applying low-E film to the inside of the window glass. This low-cost film cuts easily with scissors and clings to the glass with a misting of water.

Build a DIY Air Conditioner

You can quickly and cheaply build your own DIY air conditioner. No, this isn't the complicated, power-guzzling type that uses a compressor and refrigerant. Instead, you run an air duct through a Styrofoam cooler filled with ice. Another method uses an aquarium pump to push ice water through copper tubing attached to the front of a fan.

Add Outdoor Window Shades

Residents of tropical areas have long used exterior window shades to block the sun before it reaches the window. Varieties include Bahama shades, Bermuda shades, roller awnings, hood-style aluminum awnings, and roller shutters and sunscreens.

Plant Shade Trees and Vines

Think long-term and cool your house without AC by planting shade trees and vines. Effective shade trees include Red Maple, Autumn Blaze Maple, Sawtooth Oak, Leyland Cypress, River Birch, Tulip Tree, and Crape Myrtle.

Use Room Fans Correctly

Improve on that old standby—the box fan in the window—by setting up a pair of fans that acts like a tag team. At night, one fan in a window pushes air out of the house. On the opposite side of the house, a second fan in a straight line from the first fan pulls cool air into the house.

Replace Incandescent and Halogen Lights

Incandescent and halogen lights generate a lot of heat. In fact, incandescents release up to 90-percent of their energy as heat. Replace heat-generating lights with cooler LEDs.

Reduce or Eliminate Indoor Humidity

Humidity increases discomfort during hot days and nights. For most homes, the relative humidity target range is between 40-percent and 60-percent. Aim for the lower end of the range during hot spells. Curb humidity by limiting hot baths and showers and by avoiding cooking with boiling water (such as with pasta or rice).

Use Heat-Producing Appliances at Night

When you're trying to keep your house cool, the last thing you need is a large device blasting even more heat. Televisions, dishwashers, stoves, clothes dryers, ovens, toaster ovens, and microwaves radiate lots of extra heat. Use these devices at night or avoid them altogether.

Use Bathroom and Kitchen Fans

Along with supplemental fans you may use to cool down the house without AC, you have a few fans that are already built in: bathroom and kitchen exhaust fans. Be sure to run these fans when using the bathroom or kitchen—and keep them running until all of the heat has been expelled.

Install or Improve Attic Ventilation

Think ahead to hot summers in your home's future by installing or improving attic ventilation. Passive attic cooling systems like ridge vents, gable vents, and roof turbines use no electricity. Electric-powered whole house fans and attic fans draw off built-up heat in the attic that prevents the house from cooling down.