Blown-In Warmth for Your House

So you’ve done everything you can to warm up your house. You have new windows, you’ve filled all the drafts, re-caulked where possible, but the house still never feels warm, and you’re spending a fortune every month on heating. It could be you require more insulation to bulk up your energy rating.

The most non-invasive way to add insulation to a finished home is to blow it in. This is a procedure where loose fill material is pumped into the pre-existing wall with hoses through small openings made in the walls. Blown-in insulation is most commonly used in attics, in and around the ceiling joists.

You can do this yourself, but it is highly recommended that you employ an experienced contractor for the job. They have the specialized equipment for the job, know exactly where to start looking for the most effective placement of the insulation, and can often complete the work in less than a day. Some will even fill the holes and re-paint the walls.


There are various types of insulation to choose from, depending on your individual needs and preferences:

Fiberglass: Generally used in large batting form when initially insulating a home, the blown form consists of thin glass fibers. It’s effective in moist areas because of its ability to dry out quickly. Larger holes may need to be drilled because it takes more pressure to blow in this material.

An eco-friendly alternative to fiberglass batt insulation is made from scraps of blue jeans combined with plastic fibers treated with borate to retard flame, mould and mildew and deter insects.

Foam: This has a higher R-value than most insulation, and is an effective repellent for insects, but it can shrink and form gaps. In some cases it can expand and cause the wall or studs to bow. It has to be installed by a licensed contractor to ensure the work is done correctly. Some of these foams are toxic and contain CFC’s (chlorofluorocarbons) that are harmful to the Earth’s ozone layer, or emit off-gas formaldehyde. If you decide to go with spray foam, make sure you know what you’re getting. A green version exists in the form of a non-toxic, soy-based spray foam.

Cellulose: This is probably the most common type of blown-in insulation because of its eco-friendly properties. The material is made from recycled newsprint treated with fire retardant. It’s non-toxic and has the same R-value as most other insulations.

Possible Issues

A qualified contractor should be aware of these risks, but you should also be informed:

– Ensure the vents in the soffits are not covered over when adding insulation to this area.

– If you discover remnants of asbestos insulation in your home it should be tested before going further. Generally, it’s safe if it remains undisturbed and the toxins are not released.


Blown-in insulation is very affordable. Depending on your choice of material, the cost ranges from 60-90 cents per square foot. There may be an extra charge for drilling and painting, depending on the job. What you will gain in comfort and reduced heating and cooling bills will make it money well spent.