Sleep Better in the Summer Heat

Summer nighttime temperatures in Vermont are usually in the 50s and low 60s, allowing Vermonters to open their windows and let in cooler air for a comfortable night’s sleep. However, not every summer night is that pleasant.

Low elevation areas in Vermont like the Champlain Valley tend to see 10 to 15 nights per summer when the temperature stays above 65 degrees. Higher elevation areas such as the Northeast Kingdom usually have two to five nights per summer where the temperatures remain higher than 65.

Even one hot and muggy evening can make getting to sleep a nightmare. As humans, we are wired to sleep when the temperature drops at night. The ideal room temperature for sleeping is between 60 and 67 degrees. A cooler bedroom allows our core body temperature to drop by several degrees, stimulating the production of melatonin, the hormone that makes us sleepy. It also helps us sleep more deeply and stay asleep longer.

If the bedroom is too warm, like on a hot summer night, our core body temperature doesn’t cool down like it normally does. The brain interprets that as a signal to stay awake and alert, making getting to sleep difficult. Warm temperatures also prevent the body from entering the deep sleep stage, leading to low-quality sleep and waking up not feeling refreshed.

To make sure you’ll always get a good night’s sleep, we share these tips for sleeping better in the summer heat.

Improvements in Air Conditioning

It used to be that very few Vermont homes had air conditioning. Summers were short and fairly comfortable, so not many people saw the need for central air conditioning systems, which can be very expensive to retrofit older homes with.

As Vermont’s summers have gotten longer and warmer in recent years, the popularity of air conditioning has increased in the state. Many Vermonters have chosen to purchase ductless air source heat pumps (also known as mini-splits) that can be easily installed in existing homes without needing costly ventilation ductwork.

Even with the growing popularity of mini-splits, Vermont still has one of the lowest percentages of homes with air conditioning in the country. Only 7% of Vermont homes have centralized air conditioning, compared to 66% of all U.S. homes. About 27% of Vermont homes remain without any form of air conditioning at all.

Using a fan can help you sleep better on a warm evening, as the air moving across your skin helps evaporate sweat and assists with core temperature cool down. However, the effect of a fan can be overwhelmed by stifling heat that builds up inside a house during a hot day. The best solution for sleeping comfortably in summer remains air conditioning.

Noisy traditional window AC units can make it difficult to get to sleep for many people, especially light sleepers and those sensitive to noise. Portable floor-standing AC units, which vent air through a window insert, are now available that are very quiet (about 45 dB). These units, which can cool a bedroom to the ideal sleeping temperature, can be purchased for between $500 and $700. Look for a unit that has dual hoses to bring in outside air and expel warm air. Also look for a unit that uses an inverter design to eliminate compressor cycling noises. Units that don’t require periodically draining condensation water are more convenient.

If you want to take the plunge and install a mini-split system, check out Efficiency Vermont for information on financing options, rebates, and to find a trained installer.

Keeping Cool Without AC

If air conditioning is not an option, here are some things you can do to sleep better on a warm night without AC.

• Keep heat out of your bedroom. When a hot day is forecast, try to keep as much heat as possible out of your bedroom by closing windows and blinds. Shutting the bedroom door may also help.
• Create a cross breeze. Place a fan in a bedroom window blowing air outward. Open a second window on the opposite side of the bedroom or house, allowing cooler outside air to be drawn in. This arrangement creates a cross-breeze, which helps remove heat from your body and lowers your core temperature.
• Chill the air with ice. Spread ice cubes on a baking sheet and place in front of a fan to temporarily chill air passing over the ice. You can also use a large block of ice for a longer effect.
• Switch bed sheets to breathable fabric. Sheets made of synthetic fibers can trap heat and make you sweat. Even high thread count cotton sheets can make you hot. Instead, use more breathable fabrics like linen, bamboo, or lightweight percale cotton.
• Wear clothes made with breathable fabric. The same principle above applies to the clothes you wear while sleeping. Choose pajamas or other nighttime clothes made of lightweight, breathable fabrics like bamboo which help you stay cooler.
• Freeze sheets before bedtime. Put your pillow cases and sheets in a plastic bag and place them in the freezer for at least 20 minutes. Just before bedtime, make your bed with the chilled sheets. They won’t stay cold all night, but the effect can last long enough to help you drift off.
• Sleep in the lowest level of your house. As a house warms up during the day, heat rises and finds its way to the upper level. A bedroom that is upstairs will be warmer than the first floor. Consider creating a spot to sleep downstairs or in a finished basement, where temperatures are naturally lower.
• Take a lukewarm shower before bed. A lukewarm or moderately cool shower right at bedtime will help lower your core temperature. Avoid taking a cold shower, as that will cause your body to generate more heat to warm itself back up.
• Cool your pulse points. Apply ice packs wrapped in towels or washcloths to your body’s pulse points—the places where blood vessels are closest to the skin. These include your wrists, neck, ankles, and insides of your elbows and knees. Doing this at bedtime will help lower your core temperature. 
• Eat earlier and lighter. Don’t eat heavy evening meals as increased digestion can raise your body temperature. Opt for a light dinner and eat earlier than usual, so that digestion will be mostly completed by bedtime.

Practice Good Sleep Hygiene

When it’s hot and getting to sleep can be challenging, it’s more important than ever to practice good sleep hygiene. Limit alcohol and caffeine consumption, as those can interfere with the body’s temperature regulation. Avoid spicy and high-fat foods, which can cause indigestion that keeps you awake. Check out other ways to practice good sleep hygiene in our blog article on tips for successful sleep.