Wall insulation and energy costs are strongly related. Some experts have stated that a person can save about 15% on their energy bill by sealing up any air leaks and even adding some insulation, but that will be based on the age and location of the house.
Most newer homes have insulation, but those which were built before the 1970s and even as late as the 1980s often are not insulated. Whereas, uninsulated closed walls cause discomfort and high energy costs.
A lack of wall insulation means an overtaxed heating or cooling system which diligently blows hot or cold air, yet with a house envelope that isn’t cooperating. Here we will discuss how to add insulation to existing walls.
How To Insulate Walls Without Removing The Drywall From The Inside
To insulate a walls without removing the drywall from the inside, you can try to install injection foam and blown-in cellulose. Both options can really be beneficial to save your energy bill and improve your comfort while doing activities at the house.
Foam Injection
Foam is the material that resists mold and mildew that can give you advantages better than fiberglass insulation.

It has strong expansion properties that can force its way into difficult and impossible areas, including boxes, wires, protruding nails and screws, and other spaces that usually hang up gravity-fed cellulose.
The technique is similar to those individual cans of foam insulation. You may easily buy them but on a larger and far more efficient scale. Although professional injection foam insulation is the best, a few manufacturers offer quite expensive do-it-yourself kits. So, foam insulation then becomes the best retrofit choice without any wall damages.
Blown-In Cellulose
Actually, loose-fill cellulose insulation begins as paper and turns into insulation that fills wall cavities. Boric acid is the key ingredient as the chemical compound contributes to making safe cellulose insulation.
The process is quite complex and time-consuming. Blown-in cellulose is injected into the wall cavities by a series of holes drilled into either the inside or outside of the walls. Therefore, it’s not recommended to do your own blown-in wall insulation.
How To Insulate Finished Walls
After reading how to insulate walls without removing the drywalls, is there any chance for you to insulate finished walls?
Yes, you can exactly insulate existing walls either from outside or inside. When doing the work from outside, you should remove some siding panels so that large holes can be bored. Then professional installers usually use special equipment to blow fiberglass fibers or cellulose insulation through the holes into the cavities.
If you do it from the inside, it will involve identical working procedures but instead of removing siding, holes are cut through the drywall with a large hole saw. The procedure is a mess and requires extensive patching and painting of drywall.
There are seven stages that can help you ease the process of insulating finished walls:
- First, remove all of the old paneling on your mobile home wall with a claw hammer and a pry bar.
- Secondly, remove or tap in any nails that are protruding up from the studs with a hammer.
- We advise against removing the previous insulation because it may be very thin and include electrical wires behind or in front of it. So, let it be.
- Next, try to tape every seam where the pieces of insulation meet using duct tape.
- For each wall you’ve just insulated, try to measure, mark, and cut drywall.
- After that, attach the new drywall to the walls with a drill and 2-inch drywall screws, placing the screws vertically every 4-inches along each stud.
- Cover all seams between drywall pieces with drywall tape, then mud those seams. Allow 12 hours for the mud to dry before sanding and finishing the wall with paint or wallpaper, if you want.
This article is expected to help you understand how to insulate walls without removing the drywalls. The insulation will drastically improve thermal efficiency of the house in both summer and winter. What can be more beautiful than staying cooler when it’s hot and warmer when it’s cold?