Archive > Articles > Thermal & Moisture Control

February 2002

Building Airtight Homes

An experienced builder of energy-efficient homes explains the framing and air-sealing details necessary to build a tight, well-ventilated home.

by Steve Lentz (8 Pages)

First 100 Words:

Since 1984, I have been building energy-efficient homes with special attention to air sealing. Most conventional new homes, when tested with a blower door, show a natural infiltration rate of 4 to 8 air changes per hour; my homes are rated at 0.48 to 1.0 air changes per hour (ACH50). My package of energy-saving details costs my customers only about $1.25 per square foot, and they often make back the extra cost with just three to five years of energy savings. Since satisfied customers tell their friends about their low energy bills, my homes have been in steady demand. Building

Free View PDF | View HTML

4 Comments so far...

Super article! I look forward to more work from Mr. Lentz, who has an apparent eye for detail that some of us lack. Must say, though, that he sounds like a good candidate for building with ICFs, with their inherent tight envelope. I'd love to hear what he has to say about building unvented crawlspaces, specifically with ICFs.
Posted by: Steve Cottrell on February 27th 2002
Steve's comment about new conventional housing Natural Air Change Rate of 4 to 8, seems excessively high to me. I do Automated Performance Blower Door tests on a daily basis and what I find does not agree with that statement. Is it possible that he means 4 to 8 ACH50 (Air Changes per Hour at 50 Pascals)? If so, then I would agree with the statement. A home would need massive holes to naturally ventilate 4 or 8 times per hour! Steve's Air Change rate of .48 to 1 is not air tight at all. The Natural ACH I find on older existing homes usually ranges from .25 to 1 ACH natural and no conserted effort was made to build these home tight. Steve has an excellent reputation for building high performance homes so I'm sure it was just a terminology error.
Posted by: Hoss Hosmer on April 5th 2002
I had a kitchen fire. The Contractor did a mess of a job.My cellen is falling in. They put one up but they for got the roof witch they tryed to patch the celling. In stead of putting a new one up again. And one of the trusses were saging. So they cut the bottom of the truss without any brassing on it. Instead of it being a 1-2 inch, it is now a 1-1 inch. Now I have a real mess. What can I do about this matter? Please Help!!! Neil
Posted by: Neil Berger on April 8th 2002
I have a new construction and I have a ton of condensation in my attic. Our 2 bed room fans are now leaking water through them. I had the humity level tested last night and my kitchen and basement were 45% and my attic level was 95%,do you think that my attic may be over insulated or not vented correctly? May, I add that my home is all electric.
Posted by: joann on January 30th 2003