You can use a few different materials to insulate the space between your window air conditioner and your window frame to help improve temperature control.
Window air conditioners need to be properly insulated so that they can work as effectively and efficiently as possible.
In order to insulate the space around your air conditioner, you can add foam panels and other types of insulation materials to fill the smaller gaps between the insulation and the window frame. Proper insulation can also help retain heat in winter.
Why window air conditioners need to be insulated
Window air conditioners operate by pushing cold air into your room and hot air to the outside of your house. This is why these units need to be installed in a windowsill, so that they can properly vent and drain the outdoors.
However, if the warm air from outside your house or even the warm air that is being pushed out by the window unit while it is working, keeps finding its way back into the room, then your window air conditioner will keep cooling down the same air over and over again and this makes the entire system ineffective and inefficient.
How to insulate space on a window air conditioner
A window air conditioner that is not insulated properly will let the warm air and humidity into your space on hot days, which means that your unit will struggle to keep your space comfortable and cool and you can end up wasting a lot of energy in the process.
Although most window units do come with a window installation kit and mounting bracket, it is unlikely that the foldable side panels that these kits often come with will fill all of the gaps and spaces between the air conditioner and your window frame.
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These foldable side panels are also not always as effective at regulating the indoor temperature as other materials are, like foam boards or foam panels.
This is why many window air conditioner owners choose to install this type of insulation in the space between their window air conditioners and the window.
However, the process is not complete once this foam insulation has been installed. Just installing foam board or panels in the space around the window air conditioner can still leave small gaps through which air and dust can enter your space.
This is why you need to go the extra mile and also add other types of insulation materials to these spaces.
Insulating your window air conditioner is not only necessary to keep the warm air out of your room in the summer, but also to stop cold air from freezing up your air conditioner and your space in the winter.
How to insulate the space between your window air conditioner and window frame
In order to properly insulate the space between your window air conditioner and your window frame, you will need the following materials:
- A piece of foam board or foam panels that are big enough to fit the spaces on the sides and above the air conditioner
- A ruler and pencil
- Scissors or a box cutter tool
You need to measure the space around the window air conditioner and between the window frames, to cut the foam pieces to size, so that they will fit around the unit perfectly.
Most of these foam boards and panels have self-adhesive strips that can keep them in place, but you can also use double-sided tape.
How to insulate the space between the window air conditioner insulation and the window frame
In order to really make sure that your window air conditioner is properly insulated and that it can work as effectively and efficiently as possible, you also need to insulate the tiny gaps between the foam panels and the window frame.
Some of the best ways to do this include:
| Type of insulation | Price | Available on Amazon |
| Weather stripping | $13.99 |   |
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| Weather seal tape | $10.79 |   |
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| Expanding foam sealant | $15.87 |  |
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You can apply any of these materials all the way around the window air conditioner and around the window frame to fill any remaining spaces.
How to insulate the space inside your window air conditioner in the winter
For all intents and purposes, window air conditioners can be the same as just having a hole in your wall during winter. This can make your space feel extremely cold and can even cause your air conditioner to freeze over.
To avoid this, many air conditioner owners remove their units completely in winter. However, you can also add a plastic tarp on the inside of the removable cover over the components, or cover the entire unit with a weather-proof cover if you cannot remove the entire unit.
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