It is not recommended that you run your A/C while the house windows are open, but you should try to insulate your windows and cool down the space.
An air conditioner (A/C) lowers the temperature of your space by moving latent heat and excess moisture to the outside.
This is why running your A/C with the house windows open is not a good idea and can actually end up costing you a lot of money in the long term.
How does an air conditioner work?
An air conditioner can be such a useful addition to any home that requires cooling during the hot summer months. However, few people actually understand exactly how an air conditioner functions to lower the temperature of your space.
The process may seem complicated, but the most important thing to understand is that your air conditioner takes in the warm air that is already in the space and that is making you feel warm and passes this warm air over evaporator coils.
The evaporator coils are part of a system where refrigerant is constantly changing from a gas to a liquid in order to absorb and transport the excess heat from the air outside.
Can you run the A/C with the house windows open?
When you understand that an air conditioner cools your space by removing heat and moisture from the air in your house, and then disposes of this latent heat and moisture outside, while blowing the colder, drier air that remains back into the house to lower the temperature, it is much easier to understand the impact that an open window will have on the system and its effectivity.
Although you can technically run your A/C with the house’s windows open, it is not recommended at all, because it defeats the purpose of having the air conditioner on in the first place.
An air conditioner is designed to cool down a designated space over time, by cooling the air little by little, but when you open your house’s windows, you let all of the hot air from outside the home in again, and the air conditioner will never be able to cool down this volume of air.
In fact, running your A/C while the windows are open will actually end up costing you a lot in terms of repairs and electricity bills in the long run, and experts recommend that you do not leave the windows open.
Instead, they encourage you to ensure that any cracks and gaps in your home’s doors and windows are well-insulated to help your air conditioner work as effectively and efficiently as possible.
There are also other habits that you can implement if you feel like your air conditioner is not making your home cool enough, besides opening a window.
How running your A/C with the house windows open can damage it
When you run your A/C with your house windows open, the hot air from the outside of your house will enter your space and the cold air that the A/C blows out can dissipate outwards.
This means that your air conditioner will struggle to cool down all of this incoming hot air and the space may never reach your desired temperature.
This leads to incorrect cycling, which will cause wear and tear on some of the components, and since the air conditioner will be operating non-stop, this will increase its electricity usage. Both of these factors will end up costing you a lot of money in the long term.
How to insulate your air conditioner for it to work effectively and efficiently
Although it is not a good idea to leave your windows open while your A/C is running, it is a good idea to insulate any gaps in and around the windows and doors in your home.
This will ensure that your air conditioner can cool down your space as effectively and efficiently as possible, as no air will be leaking in or out through these gaps.
There are a variety of insulation materials that work well to fill gaps, spaces, or cracks in or around windows and window frames, but some of the most popular are weather stripping, weather sealing tape, and foam sealant.
Other ways to keep your house cool
If you feel like your air conditioner is not keeping your house cool enough and this is why you want to open your windows, there are better alternatives that will not damage your air conditioner or increase your electricity bill.
This includes drawing your curtains or blinds during the hottest times of the day. This keeps the sun out and the temperature of your home will be lower. Moreover, installing window tint along with your curtains will magnify this effect.