If you have doubts about your home’s insulation levels, and if that it is important for your energy improvement projects, consider hiring a professional energy auditor. They use infrared scanners and laser thermometers.
The alternative is to perform some simple tests yourself; they will not provide very accurate results, but they may be enough for your goals.
Looking for the type and the depth of the existing insulation
To know the insulation levels of your home's shell (walls, ceilings, floors) without professional scanners and thermometers you need to inspect each area and to look at both the...
1) type of insulation – batts, loose-fill, boards; fiberglass, cellulose, foams... and
2) its depth in inches (to evaluate the R-value).
Some areas – the attic… - may be easy to inspect, but areas like walls and flat ceilings may not be so easy. You will need to probe behind their surfaces.
Alternatives to infrared scanners and laser thermometers
To check what’s behind the surface of your walls (or ceilings, or floors…), and to avoid having to drill small holes, you may use a very basic method: checking at electrical outlets and switches.
The procedures are relatively simple, and can be effective. Just note that the levels of insulation can be different in different parts of the wall, especially in renovated areas, and that your inspections should take it into account.
The alternative - besides the professional infrared scanners and laser thermometers - is to drill small holes in hidden areas of the home's shell, or to look for exposed areas or cracks, or to inspect behind light fixtures...
The Outlet-Switch Method
Broadly, this outlet-switch method involves...
- Removing the cover plate of the switch/electrical outlet, using a screwdriver (do not forget to turn off the electricity, before you begin);
- Using a flashlight to shine into the opening.
- See what you can detect.
- Check slightly away from the box, if necessary: in many cases there is a small gap between the insulation material and the electrical box; check slightly away from it, if necessary.
- To investigate the type of insulation, you may have to use a non-metal knitting needle or something similar.
- Probe carefully and properly to not damage the electrical wiring. Do not forget that you need to determine the type of insulation - loose fill, batts… - but also its depth.
- Replace the cover plates.
This method can be used in any part of the home’s shell: common exterior walls, but also basement walls, or attic knee-walls.