Summer is fast approaching and it will soon be time to install your window air conditioners. To ensure the efficiency of your air conditioner and to keep you comfortable, simply follow these three caulking tips.

Choose a latex, silicone, or hybrid sealant

Caulking an air conditioning unit that is placed in a window requires the application of a quality sealant. Different types of sealants are available on the market, so it is, therefore, important to choose a product that is appropriate for indoor residential use.

Latex sealants are water-based and are easy to apply and clean. They can be painted to match the color of your room and are the least expensive to purchase. They are ideal for interior window caulking.

Silicone door and window sealants are UV resistant, resistant to temperature changes, have a good life span, and are flexible. It is necessary to allow a drying time when applied around the air conditioner and there is no need to paint them since paint does not adhere well to this product.

Hybrid sealants are new window caulking products. Their chemical properties combine the qualities of silicone and polyurethane sealants. They are recommended for residential applications since they do not contain solvents or isocyanates.



Be patient: wait for the right day to caulk the air conditioner you are installing in a window.

When it’s time to caulk the air conditioner unit that will be installed in a window in your home, it’s a good idea to wait for a day when the temperature is between 10°C to 25°C. You don’t want the caulking to freeze or melt.

Your workday will be easier if you install your air conditioner and caulk on a day without rain. Water that could seep between the wall and the sealant would reduce its adhesion. The weeks leading up to summer are full of perfect days to caulk your window air conditioners.


Take action by applying yourself at every step

Before caulking the air conditioner that will be installed in a window, take the time to remove the old sealant if it is not the first year of use of your air conditioner. This is an easy step, but crucial to ensure the effectiveness of your caulking. You can do this with a razor blade or knife, or with a hairdryer if it is difficult to remove. Once the old caulking has been completely removed from the air conditioner, clean the surface thoroughly with a damp sponge, and finish with a toothbrush.

 If there has never been any sealant applied to the air conditioner, you can simply clean the areas to be caulked. You’ll finally be ready to apply the sealant. First, cut the spout of the container at 45 degrees. This will facilitate the application in the corners. We then suggest that you apply your first line of caulk where it will be least visible to help you get the hang of it. Keep the same pressure during the whole operation. After applying a line of caulk, proceed to the smoothing step of this line. It is important to do this before the sealant begins to dry.

Finally, clean the area around your air conditioner. The sealant is much easier to remove at this time than when it is dry. Do not touch the caulking around or on your window air conditioner for 24 hours. 


Calfeutrage Apex is a caulking company on the south shore of Montreal. We caulk residential, commercial, and industrial buildings. For caulking quotes fill out our online form