How To Insulate Ductwork In Basement

How To Insulate Ductwork In Basement

Uninsulated ductwork in the basement may lead to increased utility bills, given the fact that it increases the time your system needs to cool or heat the house. In addition, bare ductwork wastes up to 30% of your cooled or heated air. For this reason, homeowners should consider insulating the ductwork in their basements.

When it comes down to how to insulate ductwork in basement settings, it really should be left to professionals if you have enough in your budget to do so. This will ensure proper insulation without any leaks. However, you can also choose to do the process yourself if you know how to do it properly. It takes checking for leaks, covering them, and insulating them with the right materials such as fiberglass.

Below is a step-by-step guide on how to insulate ductwork in the basement properly. The guide will help you get the work done to conserve more energy and finally reduce those problematic electric bills of yours!

A Guide On How To Insulate Ductwork In The Basement

Prepare the materials needed

Before starting any work, you should gather all the supplies you need to get the job done. This helps conserve your time and effort and ensures that everything runs smoothly. The things you need are a caulk gun, mastic, duct tape, masking tape, foil tape, a box knife, silicone tube, and fiberglass insulation (or any insulation material of your choosing.)

When picking out the insulation material you will use in your basement, check for the R-value. The higher its R-value, the better insulation it provides. Fiberglass batting with at least an R-6 rating is favorable for insulation purposes. Also, you can get foil-faced insulation. If no foil-faced insulation is available, you can use foil tape instead.

Protect yourself

When insulating ductwork, wear protective gear such as goggles, a dust mask, gloves, and protective clothing.

Clean the ductwork while checking for leaks

Before starting the insulation process, wipe down the ductwork to clean it. Next, check for possible leaks by turning on the HVAC system. If you feel air coming from the system, then it’s a sign there is a leak. However, smaller leaks are harder to detect. For small leaks, test by using an incense stick or smoke pencil. Run the stick or pencil along the ductwork and check for air leaks.

Cover the leaks

Once you find leaks, cover them with foiled duct tape. This helps prevent condensation and mold formation. Foiled duct tape is specifically made for ductwork and can handle extreme temperatures, unlike ordinary duct tape.

Measure and cut the insulation to the correct sizes

Measure the area that needs to be insulated. It is recommended you add two inches on both the width and length measurements to keep the insulation securely installed around the ductwork. Cut your insulation material accurately and precisely.

Wrap and secure

How to Insulate Ductwork in Basement
Source: J.A. Dunbar

Slide the insulation around the duct, starting from the bottom. Use properly sized cuts and make sure that both ends of the insulation meet at the top. Tightly secure the insulation in place, but do not compress or dent the ductwork when doing so.

If you use foil-faced insulation, the foil part should be visible on the outside of the ductwork, and the fiberglass insulation touches the ductwork.

Put the duct tape in place to secure the insulation. Wrap the tape around the insulation and the ductwork. Finish it off with foil tape. Close up the ends of the insulation completely by placing one long piece of foil tape along its entire length.

Repeat the above steps

Repeat the steps above until all the ductwork in your basement is completely covered. Do not leave any gaps along the length of the ductwork. Make sure that everything is covered with insulation and foil.

Check and confirm that everything is covered

Examine the ductwork and make sure that each area is properly covered and insulated. You should not find any areas where heated or cooled air has the chance to escape.

Additional Tip: You can use mastic to seal off an area where you cannot fit and seal the insulation properly. Using a caulking gun, apply mastic to the closure of the insulation to seal it off properly.

Frequently Asked Questions

How much does it cost to insulate ductwork?

The average duct insulation cost ranges between $0.95 to $2.00 per sq. ft. Various factors affect the final cost, such as the insulation material used, R-value of the insulation material, ease of access to the ductwork, and whether you choose to have an expert do the insulation or do it yourself.

What is the best insulation for ductwork?

Knowing how to insulate ductwork in the basement requires you to know the best material to use. For insulating ductwork, the most effective choice is fiberglass. Unfortunately, this might be more expensive than other choices on the market. For this reason, not many people choose this insulation material for their basement ductwork.

Is mineral wool insulation worth the price?

Mineral wool is an expensive insulation material that has a more superior R-value than fiberglass insulation. Mineral wool contains 70% recycled material, which makes it an eco-friendly choice for insulation. It also helps reduce sound, thanks to its higher density. Additionally, mineral wool insulation is also water-resistant and fire-resistant.

Is it worth insulating ductwork?

Though some people do not insulate ductwork because it can prove to be costly and labor-intensive, the benefits of insulating ductwork in the basement make it worthy in the long run. Because ductwork insulation helps the air traveling in the system stay at a specific temperature, it helps conserve more energy in the home. Not only will this help decrease your energy consumption and electric bill, but it will also help prolong the life of your HVAC system.

How do you choose the R-value rating of the insulation material for ductwork?

Most HVAC contractors recommend ductwork insulation with at least a 6 R-value rating. However, insulation materials with an R-value of 8 are mostly preferred.

How long will it take to insulate ductwork in the basement?

Professionals who know how to insulate ductwork in the basement can finish the whole process in one day or less. But if you do it by yourself, you can finish it within 1 to 2 days. The primary factor affecting the insulation time depends on how much ductwork you have in the basement. Your skill will also determine how fast or slow you are in completing the insulation work yourself.

Can you use spray foam insulation on basement ductwork?

Once you have checked each air duct for leaks, you can then use spray foam insulation to encapsulate the ducts and increase the R-value of the ductwork while also reducing air leakage.