This is how to cool down a bedroom fast, even if you don't have an air conditioner

Summer is upon us, and while many of us enjoy basking in the heat and sun outdoors during the day, it’s a very different story trying to sleep at night. An overly warm bedroom can make sleep difficult, sometimes even impossible. 

Of course, for those of us with air conditioning, keeping a bedroom cool is easily solved by turning down your thermostat. But what if you don’t have air conditioning, or it has failed for whatever reason? Depending on where your bedroom is located it will heat up before you know it - so, how do you cool it down, and fast, before you get into bed? 

We’ve consulted HVAC professionals; here are their top tips for cooling down a bedroom fast. Plus, we’ll explore a few of the common issues around being too hot at night and how to fix them.

1. Take measures to cool down bedroom during the day

Cooling a room that's a little stuffy takes much less time than one that's boiling. While it’s understandable that you may not always be able to control the temperature in your bedroom - for example, if you’re away from home for a week - there is still a lot you can do to prevent your bedroom from getting too hot in the first place. 

If the sun hits your bedroom directly during the day, you need to invest in heavier or blackout shades for your bedroom windows. Guy Caldwell, HVAC Master Instructor at The Refrigeration School, highly recommends installing ‘heavier window shades and closing them during the day when the sun is beating in through the windows.’ 

When choosing your shades or blinds, look for one made from a material that has thermal insulation/UV protection. Thermal insulation shades (which can be bought on Amazon) are made from a thicker fabric than regular shades and are better at keeping the heat out of your bedroom. If you live in a climate with cold winters, they’ll also be useful for keeping the cold out. 

Keeping your blackout blinds down throughout the day is the bare minimum you can do to keep your bedroom cooler at night. The less your bedroom heats up during the day, the less time and effort you’ll need to put in to cool it down at night.  

2. Keep your ceiling fan running

If you have a ceiling fan, keep it running, ’Leaving your fan running helps maintain constant air circulation and keeps temperatures consistent throughout your room,' says Caldwell. 

Make sure that the ceiling fan is running counterclockwise during the summer months: this creates a breeze by pushing the air around, which in turn helps cool down your bedroom. 

Don’t worry too much about the energy costs: even if you left a standard ceiling fan running 24 hours a day, you likely would only pay around 84 cents per week. 

Guy Caldwell

Guy Caldwell is an HVAC Master Instructor at The Refrigeration School, Inc. (RSI) in Phoenix, Arizona. Guy has been in the electrical and HVAC/R field for over 18 years, and currently works to train future HVAC/R technicians at RSI.

3. Be strategic about when you open windows

The most obvious solution to a hot bedroom is…opening the window, right? Yes, but only if the outside air is cooler than the air inside. Depending on how hot it gets where you live, this may not be the case, so opening the window may sound like a moot point. 

Nevertheless, it’s still a good idea to open the window. According to a 2015 study, ventilating the bedroom with outdoor air reduces the amount of carbon monoxide in your blood, improving sleep. The trick is to do this after the heat begins to subside, usually during the second half of the night, in the hours leading up to dawn. 

Avoid opening the window during the afternoon and early evening when the heat that's been absorbed by sidewalks and buildings rises into the air, making it stuffy and hot. 

4. Invest in a high-CFM oscillating fan

Despite the ongoing ceiling fan vs air conditioners debate, in our opinion, ceiling fans are a staple in any bedroom. However, if you are finding that a ceiling fan alone just isn’t reducing the temperature in your bedroom enough, it’s time to invest in an oscillating fan as well. 

If you want to cool down a bedroom fast, you need a model that's more powerful than your average fan. Ronald Raymond, an engineer and owner of HVAC solutions provider RSE Energy Group, recommends seeking out a quiet-rated, high-CFM (Cubic Feet of Air per Minute) fan: ‘The greater the CFM, the greater the airflow, making it more effective at cooling your bedroom. Optimum cooling CFM range would be 1600 to 3000,’ advises Raymond.  

If you have a smaller bedroom (under 150 square feet), you may be able to get away with a CFM of 1,000. The Dyson Tower Fan, for example, has a CFU of 1,000 - good for a smaller bedroom, but likely not very effective if used on its own in a larger master bedroom.  Fans with lower velocity than 1,000 generally won’t be effective at cooling down your bedroom - keep those smaller, less powerful fans for your home office desk. 

If you can’t find a fan that is powerful and quiet enough, just use multiple fans. Asif Bux, Owner & Service Manager at Comfort Union, an HVAC & plumbing company, says that ‘using multiple fans to create cross-ventilation can significantly lower the room temperature by circulating the air more effectively.’

Asif Bux

Asif Bux proudly leads Comfort Union, a licensed HVAC, Plumbing and Electrical company in Calgary, Alberta. He is a licensed gasfitter with an eclectic background in Chemical Engineering and Business.

5. Pay attention to humidity

Humid air feels hotter: the higher the humidity of the surrounding air, the less easily sweat evaporates from your body, which is how we keep cool when hot. If you live in a humid climate or have high humidity levels in your home, getting a dehumidifier can vastly improve your sleeping environment. 

The best dehumidifiers won’t cool the air in your bedroom, but they will help you keep cooler by making the air more comfortable. They work fast too, so you should begin to feel a difference in as little as half an hour.

6. Use the power of cold water

We've covered humid air. But air that is too dry is also uncomfortable, especially for your respiratory system, and you may need to add humidity if it is lower than 45% in your bedroom. The fastest way to do this is by placing large bowls of ice-cold water or damp towels in front of your fans.

‘Placing large bowls of water or damp cloths near airflow can help reduce room temperature through evaporation, especially in dry climates,’ says Asif Bux. 

7. Invest in a portable air conditioner

A fast and reliable to cool down a very hot bedroom is with a portable air conditioner. It’s a good idea to have one in your home, even if your bedroom is comfortable most of the time. Heatwaves, in particular, can wreak havoc on bedroom temperatures, making otherwise comfortable bedrooms unbearable to sleep in.

Portable air conditioners are not fans; they work in the same way as built-in air conditioners via condenser coils. They’re just not permanently built into your wall or window. You will need to place the hose outside, either through a window or door. Financially, portable air conditioners are more of an investment than fans, although Amazon Basics offers a decent model for under $400.  

Aesthetically, having a hose sticking out from your bedroom window isn’t the greatest option, but air conditioning is air conditioning: it works, and it works fast. Only you know if your bedroom heat problem is bad enough to warrant the cost of installing central air conditioning. 

8. Rethink your bedding

While a hot bedroom will be uncomfortable no matter what you sleep on, your choice of bedding will make a difference to your overall comfort once you get the bedroom temperature under control. 

Try to avoid synthetic materials and feathers/down. These tend to make you hot at night because they’re insulators. The best sheets for sleeping are body temperature regulators, such as wool and silk. As for your bedlinen, stick to natural textiles like cotton, linen, and silk; avoid polyester and polyester-blend sheets.

What you consider to be the bedroom temperature for sleep may well be too warm or too cold for your partner if you share a bedroom. However, according to The Sleep Foundation, the ideal bedroom temperature for sleeping is 65°F (18.3°C). At any rate, most people find temperatures up to 68F (20C) comfortable. Anything above 68°F likely will affect your sleep quality. Having said that, a bedroom that is cold can also prevent you from sleeping.