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Real Estate Insights from Real Estate Insiders

How to Insulate an Existing House

Every house owner dreams of making the home energy efficient. It helps in reducing the utility bills. A great way to achieve that is by adding insulation to the house. You will be surprised to know that homeowners have been capable of getting a reduction of about 10 percent in the electric bills after the addition of insulation.

Many homes do not have enough insulation within the walls, which results in heat loss. However, once you install the insulation within the house's existing walls, you can reduce the dependency on the cooling and heating gadgets. As you will read this article, you will learn the techniques to insulate the home with the existing walls and save on energy costs.

Evaluation and inspection of the insulation

To begin with, it is necessary to inspect and evaluate the floors, walls, and attic present adjacent to the unheated space. A significant amount of heat in the average house is lost through these places. Instead of insulating the whole home, you should look for any cracks or gaps in these places. If gaps are present in them, the warm air might travel into the attic through the ceiling. Hence, you should make sure to seal them with the aid of the right seal. You can make use of an electric outlet to inspect the exterior walls of the house:

  • At first, you should switch the power of the outlet off.
  • Now, you need to remove its outlet cover and throw a light upon the crack present around the outlet box. Take a closer look, whether there is insulation within the house's wall. Besides this, you should also check out the thickness of the insulation.
  • In this step, you require pulling a small amount of insulation to understand the kind of insulation it has.
  • Here, you need to inspect and evaluate all the outlets on the floor. You need to keep in mind that if insulation is present in one wall, it does not indicate that it is present in every place.
  • Remember to inspect and check out the insulation's thickness present in the unfinished basement ceilings and walls. If there is no ventilation into the crawlspace, there might be insulation within the perimeter walls. For the relatively new house, insulation might be present outside the foundation walls and basement. Even if they are present, they might not be visible under the naked eye. To know about this, you can contact the original owner or builder of the house to seek information about the house's exterior insulation.
  • After determining the insulation present in the house, you need to figure out the R-value of the insulation installed in the home previously.
  • As you find the insulation's R-values, you can make the best use of the Home Energy Saver tool for determining the amount of insulation necessary for maximum energy efficiency.

Decide the kind of insulation you want to add.

Once you make your mind add the insulation, you should review the below details. It will be beneficial in deciding the kind of insulation you need to use:


The attic happens to be the best place to add insulation without a negative impact on the drywall. You will reap a bunch of benefits as you add insulation to the attic under the roof. To do this, you can consider adding loose fill insulation like fiberglass beads, rock wool, and cellulose.

You can find such insulation within the bags, available at the supply stores of the building. Loose fill is dry fits of insulation that are blown through holes into the wall cavities. There are primarily three kinds of loose fill, which include untreated, fiberglass, and mineral wool.

Spray foam

It is another worth mentioning option for insulating the house without the need to remove the drywall. This specific poly material liquid expands after coming in contact with air. There are primarily two techniques to install the spray foam, including the high-density spray foam and low-density spray foam. They act as the air barrier for filling the crevices. As no opening remains left, there will be no scopes for the entry of cold air or hot air release.

Spray foam is one of the prominent choices for insulating the house owing to its incredible effectiveness. As it can fill the holes, the house owner does not encounter any issues for maintaining the efficacy.

Batt insulation

The roll or batt insulation is another type of insulation for the attic. The batts refer to fluffy blankets available in precut pads or long rolls to ensure a perfect fitting between the studs. While they are primarily composed of fiberglass, they are also found in the materials of mineral wool, cotton, and real sheep's wool.

You can purchase them from the building supply stores. They are primarily placed during the construction of the house walls between the studs. At times, they are laid above the current loose fill insulation or between the ceiling joists.


It is possible to add insulation to the house's existing walls without eliminating the drywall. Here are the steps you should follow to achieve this:

  • The first step involves cutting the holes present in the exterior siding. To do this, you can blow spray foam or fill cellulose from the outside into the walls by using similar techniques. So, you should make sure to cut a hole of about 2 inches diameter on the wall's top and between the studs pair.
  • Next to this, you should make sure to spray foam or cellulose with a hose within the cavity.
  • The next step involves replacing the hole cutouts and filling the same with sand smooth, wood filler, and paint to restore the siding.

Every house owner feels tempted to insulate the house to enjoy a comfortable living. In addition to following the steps mentioned above, you can consider hiring a professional. They can lend a helping hand in insulating the house with the existing walls.

If you are looking for a suitable option on how to insulate a house with existing walls, you should make sure to follow the above-mentioned steps.