My Experience
There may be some obvious places to add or improve insulation that makes sense even to amateurs. Once you understand the type you need and the best and safest way to install, go to it!
However, professionals know best: I took the energy efficiency auditor’s advice on where and how to add insulation. Usually, I first make the changes I know of, then invite the auditor to review my work and discover what I missed (usually a lot). In our case, the auditors found a few situations where there was no insulation (above a door, an old dairy drop-off location) that once fixed, really warmed up our cold spots.
Remember when you improve insulation, you are helping yourself both now and in the future as well as reducing your environmental footprint. Before you start, get a record of your previous year’s energy history from your energy provider. After you are done, I would love to see your before and after results!
Your Choices
Construction is usually built according to government code, and code has advanced over the years. However, code is the minimum and should not be construed as necessarily sufficient or best. Therefore, even in new homes, adding insulation may be well worth your effort. An energy auditor will make professional insulation recommendations, including potentially others not suggested here.
| Improve Insulation Action Items and Links | Notes |
| Purchase Insulation Appropriate for Your Area | Brief description of insulation types and values |
| Add to Your Attic Insulation | May do yourself |
| Add to Wall Insulation | Requires professional installation |
| Parent Link: Ways to Save Energy | Considers other home energy efficiency possibilities |
Purchase Insulation Appropriate for Your Area
The R-value measures resistance to heat transfer, and increasing numbers mean better insulation (Holladay, 2017). The R-value is always indicated on the packaging. Different climates have different recommendations for R-values, so local stores will likely indicate what ratings are useful in your neighborhood for walls, ground floors, and attics. U values are the reciprocal: R-value = 1/U-value; therefore lower U-values have better insulation properties.
Different types of insulation include fiberglass, cellulose and rigid foam board (Harley, 2012)(Holladay, 2017).
- Fiberglass is itchy, but fairly easy to lay and is cheap. Fiberglass is air permeable, so wind blows through fiberglass reducing insulation value when the home is not sealed properly. Using fiberglass in combination with drywall or foam board can seal air leaks. It is preferable to use 1-inch oversized batts to leave no gaps; otherwise fill any gaps or seams with additional loose fiberglass or cellulose.
- Cellulose is primarily shredded newspaper, and is warmer and tighter than fiberglass. Cellulose is usually blown in by experts into wall or other home cavities. Cellulose should not be used near anything flammable, such as a chimney or recessed lights.
- Polyurethene Foam: is more expensive, professionally installed, and is more air tight than fiberglass or cellulose.
- Foam board is high-performance and rigid, but only 1 inch thick. An advantage of foam board is it is not air permeable; seams should be caulked to prevent air leaks. In hot climates, polyiso is effective; in cold climates, expanded polystyrene (EPS) is recommended. Both types are environmentally friendly.
Add to Your Attic Insulation
For attics, R-38 is the minimum recommended, increasing for northern climates to R-50 or R-60 (Harley, 2012). To estimate your attic insulation level, determine the insulation type, learn its R-rating, and measure the thickness of the insulation. To add insulation, lay new batts down vertically across existing insulation (Amann et al., 2012). Harley (2012) says you will benefit the most from the first 6 inches of insulation but gain savings from the next 6 inches. Fiberglass and cellulose insulation must be fluffed to achieve the R-rating advertised on the packaging.
If you observe stained or dirty insulation, it is a sign of air leakage through that insulation (Holladay, 2017). Seal the air leakage before adding insulation.
It is recommended to wear a respirator and safety glasses when installing new insulation, to protect yourself from the new – and any existing – insulation. Older insulation, such as brown and grainy vermiculite, may contain traces of dangerous asbestos.
Improve Wall Insulation
Homes built before 1960 may have little to no insulation in the walls. Cellulose insulation can be blown in by drilling holes in the external siding (wood, vinyl or shingle siding); filled holes may show in wood walls after completion unless covered with siding. During installation, someone should be inside monitoring for problems, e.g., insulation falling into the basement (Harley, 2012). Basement foundation walls also benefit from insulation but must be done expertly to avoid mold issues (Amann et al., 2012).
Also read section on Seal House Envelope for additional insulation ideas.
References
- Amann, Jennifer Thorne, Wilson, Alex, and Ackerly, Katie (2012) Consumer Guide to Home Energy Savings, 10th edition. New Society Publishers, Gabriola Island, BC Canada.
- Harley, Bruce (2012) Insulate and Weatherize for Energy Efficiency at Home. The Taunton Press, Newtown CT.
- Holladay, Martin (2017) Musings of an Energy Nerd: Toward an Energy Efficient Home, TheTaunton Press, Newton CT.