What Should be in Every New Home and Why -- Part 3-- Insulation

Homes that conform to new code are better than last year’s homes, but do you want a home that just conforms to code or one that takes advantage of technology, considers energy conservation, raises livability to a whole new level, and does so affordably?

Ask the builder: What type of insulation is in the home?

Fiberglass batting and blown-in fiberglass insulation have been the choice of most home builders for the last 50 years. More recently, other types of insulation have gained popularity as we study how fiberglass fails when outside temperatures fall below 45 degrees. According to a study at Oak Ridge National Laboratories, funded by the Department of Energy, the printed “R” values of batting insulation are inaccurate.
The study states that:
• “R-19” labeled fiberglass batts have an actual R-value of 17.4 before they are installed.
• “R-19” fiberglass batts have an actual R-value of 17.0 when installed “perfectly”
• “R-19” fiberglass batts have an actual R-value of 13.7 when installed as commonly found in actual walls. This represents a 28% loss in the actual R-value versus what is printed on the label.
(Read the details of the study at http://envirosealfoam.com/fiberglassbatts.pdf)

Make sure any home you’re considering uses open cell spray foam insulation. Open cell spray foam insulation expands during its application which helps it find and fill every crevice that might leak air. Batting leaves gaps around its perimeter in every wall cavity and at any seams. It’s impossible to squeeze it into all of the possible air leaks even if the installer can find them. In addition, open cell foam does not allow moisture transfer as fiberglass batting does.

Ask the builder: How many air changes per hour in this home?

Air Changes per Hour (or ACH) are calculated using a blower door test where all of the doors and windows are closed and the front door is replaced with a sealed fan that creates a controlled negative pressure inside the home. A gauge measures how many times the air inside the home is completely changed in an hour under this negative pressure. The ACH score of a home reveals how tightly sealed against outside infiltration it is. A lower score represents a more tightly sealed home.

The typical house, built to current code, usually scores 10 Air Changes per Hour (ACH). To qualify for the Energy Star rating a house can score no higher than 7 ACH. Look for a score of under 3 ACH for homes that are 70% better than standard homes. Infiltration typically represents 25-30% of the heating and cooling cost of a house so its ACH score is important. Lower energy usage is better for the homeowner and for the environment.

Mark Mecklem - Miranda Homes

Next: Part 4 - Heating/Ventilation/Air Conditioning