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What Does Caulking Mean And Why Is It Important?

May 04, 2015

Air Conditioning
A service technician talking to a man in the basement by a Lennox furnace installed by romaniuk heating.


A furnace is not something that you install at your home and then forget about. As winters get warm and more comfortable with the arrival of your furnace, after-care and maintenance of the furnace comes with the package. So do problems and breakdowns. Those who have had a Furnace installed in their house will be familiar with the common problem of furnace gaps or spaces. These are caused by sheet metal joints that are loosely fit or are not mounted properly. The modern furnace witnesses a lot of furnace gaps because of its structure. There are separations from the fan housing, the heat exchanger and the filter cover which can give rise to these crevices. This is where Caulking comes to our rescue.

What is caulking?

Caulking is the process of sealing joints or cracks on a structure (in a furnace in this case) or even pipes (PVC pipes, furnace vents), using a strong adhesive or sealing element called the “caulk”. Chemicals such as Silicone, Polyurethane and Polysulfide are some of the most commonly used caulks. Caulks should be chosen depending on the problem-area or the area that needs a sealing. For instance, imagine a gap around your furnace vent that needs sealing. You need something that can withstand the high heat, considering the part gets quite hot. Well, that`s what we`re talking about! Once you determine the problem-area, pick the right type of caulk from the nearby hardware store and get to work (if you intend to do it yourself).

Choosing the right caulk

When it comes to your furnace, a normal adhesive wouldn`t do. You need something that can stand the high temperatures and still continues to do its work. One of the most appropriate caulks to be used in/ on the furnace is the silicone caulk. The silicone caulk works on most surfaces except concrete. It is extremely durable and can withstand temperatures up to 400 degrees. But all this greatness comes with an extra price; this caulk happens to be a little high-priced. You can also consider foaming sealants for caulking, although they may not be as effective as the silicone caulk.

The perils of a furnace without caulking

Caulking is very important for the longevity and efficiency of your heating unit. Ever wondered what harm could these narrow gaps on the furnace vents possibly do? The answer is – a lot. They can cause air-leaks and affect the overall performance of your unit. The air-leaks are a potential health hazard and can lead to your hospital bills. The inefficiency, on the other hand, can result in higher electricity bills as an inefficient unit consumes a lot of power. This is why it is extremely important to fill up/seal these gaps as soon as possible. Unattended gaps only lead to bigger problems.

Expert tip – Apart from the Silicone caulk, a foaming sealant can also be used. They can be used separately or together. For deeper gaps, you can inject the silicone as far as it reaches, on the inner side. Once, this has been done, you can cover the outer regions with the foaming sealant and your furnace is good to go.