This is one of our most often-asked questions during a home inspection. Several considerations go into making that decision:

•• What insulation does the house have in the walls and, if it’s an older house with elevated floors, under the floor? As part of our infrared evaluation of the building envelope, we will determine what insulation you have in these areas. If none, then adding insulation where it is missing will be more effective for the overall energy efficiency and comfort in the home. 

    Floor insulation is more difficult and expensive to install than attic insulation, because it must be secured in place--often in a difficult, tight workspace; and retrofitting insulation into an existing wall is way more expensive. So adding more attic insulation is usually the cheapest, if not the best, solution.

•• Is the existing attic insulation adequate? The effectiveness of insulation deteriorates as it compresses over time and from workmen climbing over it. We will give you an estimate of the R-value of the current attic insulation as part of your home inspection. Also, homeowners expect a higher insulation level today, so adding some blown insulation over the original material pushes it up to todays’s standards. 

    However, when the new insulation is being installed, make sure the the contractor does not obstruct the the soffit vents at the edge of the roof. Blocked vents will stop the necessary ventilation of the attic and end up negating the gains from the new insulation.

•• Have you explored all your alternatives with an insulation contractor? There are reflective foil panels, rigid insulation that can installed under new roofing, attic ventilation improvements, and other solutions besides just blowing more insulation in the attic.

    To check out what insulation is already in place in a home, visit our blog How can I tell if a house has insulation? And for an overview of what can go wrong, see our blog post What are the common problems with attic insulation? 

    Visit our INSULATION page for other related blog posts on this subject, or go to the INDEX for a complete listing of all our articles.