Can I Save Energy by Sleeping With My Windows Open?

April 14, 2022
Updated: February 16, 2024

opened windowIt can feel refreshing to open your windows in the evenings and let the cool outdoor air in. Fresh air, especially during the evening in Seattle, is conducive to a good night’s sleep. As the outdoor air gets cooler, you may wonder if it is best to open your windows at night and turn off your air conditioning. While opening your window at night does improve natural ventilation and might reduce your energy bill, there are several factors to consider before ditching your AC for open windows.

The Pros and Cons of Natural Air Ventilation

Your home is a collection point for contaminants. Some contaminants come from the paint on your walls, your carpet, the chemicals you use to clean your home, and your furniture. These contaminants can impact your family’s health. Conversely, outdoor air can be cleaner.

If you open two windows on opposite sides of your home, you can get a nice cross breeze that will push bad air out and let good air in. Additionally, allowing cool air to flow through your home at night could reduce the burden on your AC unit. This could extend the life of your AC unit.

On the downside, it’s impossible to leave your windows open every night. Also, as nice as fresh outdoor air is, the reality is that the air in Seattle is not the cleanest. If you live by a busy road, you allow pollutants from vehicles and other sources to enter your home.

Can I Keep My Windows Open at Night and Use the AC During the Day?

This seems like a good strategy. However, contrary to conventional wisdom, opening your windows at night during the summer may not always lower your energy bill. It could have the opposite effect. Typically, even in the evening, outdoor air during the summer is warmer than the air in your home. So, your air conditioner has to work harder to cool your home.

Since the air in your house is cooler than the air outdoors, entropy will force the cold air from in your home outdoors and pull in the warmer air. The next day, if you turn your AC unit back on, it will have to work harder to bring your home down to a comfortable temperature. This is going to cost you more in energy bills.

An air conditioner cools your home by swapping heated air for cool air and removing the humidity from the air. If you let air with moisture into your home at nighttime, even if the outdoor air is cooler than that air inside your home, things become uncomfortable. Your AC unit will work harder to remove that humidity from your home. This is going to cost you more money.

When Is a Good Time to Open the Windows at Night?

During the late fall months in Seattle, outdoor temperatures can drop well below 70 degrees. This is when you might benefit from turning off the AC and opening the windows. The only caveat is that humidity levels must be low.

If you opt to sleep with your windows open at night to take advantage of the cool air, you want to try to trap that cool air in your home in the morning. As soon as you wake up, close your blinds and windows to keep the cool air indoors. If you wait until late in the morning, the outdoor air will have heated up to the point where any cool air in your home will have dissipated. The cooler you can keep your home’s indoor air, the less your air conditioning unit has to work, and the less you spend on energy bills.

No matter if you use your air conditioning unit intermittently or have it constantly running, the best way to save energy is to keep your AC unit in good repair. Our technicians at Brennan Heating & Air Conditioning will be happy to visit your home and ensure that your AC unit works at peak proficiency.

Contact Brennan Heating & Air Conditioning for AC service!

Can I Open My Windows and Keep My AC Unit Running at Night?

Yes. However, it may not be the best for your pocketbook or air conditioning unit.

When Brennan Heating & Air Conditioning professionals install an air conditioner in your Seattle home, we do so based on our calculation of the load necessary for your unit. We want your home to be cooled efficiently. If you open a window, the load on your AC unit increases. The unit must work harder to keep your home at a set temperature while replacing the cool air escaping out the windows.

Turn your AC unit off if you want to sleep with the windows open. This will protect your unit from overheating and breaking down prematurely. There is no reason to spend money on energy to cool your home for it to fly out the windows.

Open Windows and Indoor Air Quality

When your windows are open, you are letting a bunch of debris in your home. Dust, pollen, and mold spores will reduce your indoor air quality and coat your home’s surfaces. Although the fresh outdoor air may smell good at night, it can come at a cost. For example, if it rains while you sleep, you could wake up and find your floors drenched with water. Mold and moisture remediation resulting from this rain infiltration will cost you way more than you might save by turning off your AC unit at night.

Ways to Save Money on Air Conditioning

The cooler you can keep your indoor temperature, the less you will spend on air conditioning. One thing you can do is to keep your curtains or blinds closed, preventing sunlight from entering your home and warming it up.

Consider installing window tinting. On its own, window tinting will not keep your home cool. However, if you combine it with curtains, it can make your home drastically cooler.

Finally, make sure that you have proper insulation. If not, when you turn your AC unit on, heat from outside will be transferred into your home. This forces your AC unit to work harder and makes the overall cooling of your home more expensive.

Your AC Unit Was Built to Run

Your AC unit was designed to run for extended amounts of time. If you leave your HVAC system shut down for a long time, it can collect dust and debris and suffer damage. You purchased your AC unit to keep your home cool. So use it.

Work With Seattle’s Best HVAC and Electrical Company

For more than three decades, Brennan Heating & Air Conditioning has been committed to ensuring our customers are comfortable year-round. We offer Seattle residents, as well as those in nearby counties, the best HVAC services. We offer 24/7 HVAC repair and maintenance services as well as professional HVAC and electrical installation. We provide free energy consultations and do all sorts of residential electrical work.

We guarantee our workmanship, and we treat your home respectfully. Our knowledgeable technicians will keep things running smoothly in your home for years to come. Contact Brennan Heating & Air Conditioning today to learn why we are the trusted name in HVAC and electrical work in our area.

Brennan Heating & Cooling icon