Extension and Ag Research News


Adequate Insulation Keeps Home Warm, Saves Money

A good time to add insulation is when you’re remodeling or residing.

Wrapping your house in a warm blanket will keep you more comfortable and save you money by reducing energy costs.

Now is a good time to inspect your home’s “blanket,” says Ken Hellevang, North Dakota State University Extension Service agricultural engineer. Homeowners planning remodeling or re-siding projects this summer should take a look at their home’s insulation levels because those are good opportunities to add any necessary insulation and seal air leaks.

Russ Schell, owner of RJ Energy Solutions in Fargo, who advises small businesses and homeowners about more energy-efficient practices, discovers missing or inadequate insulation by using a thermal imaging camera to detect cold spots in a home’s walls or ceilings. In one home he assessed, adding insulation to areas where it was missing or inadequate would save up to 35 percent in energy costs, he says.

Homeowners may be surprised at the amount of warm air leaking from their home during the winter.

“Actually, the gaps are sometimes quite significant,” Schell says.

For do-it-yourself detection of cold spots, homeowners can borrow an infrared thermometer from their county’s NDSU Extension Service office to check for air leaks and cold spots. An accompanying publication, “Determining Insulation and Air Infiltration Levels: Using an Infrared Thermometer,” explains how to use the thermometer. It is available at https://www.ag.ndsu.edu/pubs/ageng/structu/ae1373.pdf.

“It’s a nice way to do an initial assessment,” Hellevang says.

Insulation is rated in an R-value, which is its capacity to resist heat flow. The higher the R-value, the greater the insulating power.

Insulation of R-49 to R-60 is recommended in an attic space, while R-13 to R-21 is recommended in a wall cavity. The type of insulation and its thickness will determine its R-value. For details, see the NDSU publication “Insulating to Reduce Heating Costs.” It can be found at https://www.ag.ndsu.edu/pubs/ageng/structu/ae1368.pdf.

Fiberglass batt insulation, for example, has an R-value of 3 to 3.5 per inch, so 3.5 inches of insulation would equal approximately R-13.

“That’s the minimum insulation level recommended, but it is difficult to increase that in an existing 2 by 4 stud wall,” Hellevang says. “You’re typically looking at opening up the walls, either internally or externally.”

Homeowners need to consider the ratio of improvement in the insulation level (future value divided by existing value) as they analyze an insulation project, he notes. While adding insulation may not be economical unless a homeowner is remodeling or re-siding a home, incorporating rigid polystyrene insulation during such a project can increase the R-value significantly.

Schell cites a homeowner with an older home who opted to open the walls to incorporate closed-cell polyurethane foam insulation. The homeowner decreased his heating bills by 60 percent.

“If he went from an R-5 to an R-20, he’s going to see a huge improvement, so it’s worth doing more extensive remodeling,” Hellevang says.

Even with a reasonable indoor temperature, homes can feel colder due to insufficient insulation.

“If we have a wall that is cold, heat is radiating, or moving, from our body to that cold wall, and we end up feeling cold,” Hellevang says. “So by insulating our home, not only are we reducing the heat loss, but we’re going to make that home more comfortable because adding insulation warms the inside wall surface, which then reduces the amount of that radiation heat loss, and we feel warmer.”

Homeowners also should be aware of gaps in the insulation.

“It’s always easy to insulate the middle portion of your house attic, but when you start getting closer to the edge of the house, that’s where we often see missing insulation in ceilings,” Schell says.

Other areas that may have gaps with inadequate insulation are around windows and doors, behind electrical outlets, near the ceiling in a wall and in corners.

Homeowners should watch for visual clues of insufficient insulation, such as frost or snow on the roof melting quicker than on neighboring roofs, or uneven patterns of frost on a roof. Condensation may form on cool spots on the wall or ceiling.

“Some of these visual clues are a good message,” Hellevang says.

Homeowners also should look for air leaks in their home, where valuable energy is wasted.

“We can do a good job of insulating, but if we still leave an opening for air to get through, particularly with fiberglass or loose insulations, that air will carry the heat through the insulation and out of the living space,” Hellevang says.

Seal openings between the living space and the attic or outside walls, such as openings for plumbing, electrical outlets or recessed lights. Also add foam covers behind outlets, seal the attic hatch, and caulk or weather-strip around windows and doors.

To learn more about sealing a home, check out the NDSU publication “Home Envelope,” found at https://www.ag.ndsu.edu/pubs/ageng/structu/ae1616.pdf.

NDSU Agriculture Communication - April 19, 2016

Source:Ken Hellevang, 701-231-7243, kenneth.hellevang@ndsu.edu
Editor:Luann Dart, 701-584-2172, luann@westriv.com
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