David Richardson posted an interesting piece on changing from % based testing based on conditioned floor area versus the duct area

http://ncidavid.blogspot.com/2013/10/should-duct-surface-area-be-us... 

Personally I see quite a few problems with this based on the way things are done now, but I am curious what you all think.

As for some of my concerns - most installers have no clue what the duct area is because we cant even get them to do a Manual J much less a D (sorry I also have no desire to run a tape against them either)

Leaving the air handler out means more sloppy installs of them & manufacturers wouldn't have to concentrate on making them by default tighter

With that he does make some very valid points & I would love to hear your thoughts

Views: 563

Replies to This Discussion

Interesting thought but the issue with that is contractors bumping up manual J's for bigger units - the 99 occupants, leaky house, etc... tricks we have all seen used to get to there favorite 400 or 500 SF per ton. Granted commercial never sees this issue but that is because they require a mechanical engineer in many cases & also have higher loads than residential due to ventilation requirements

I think John has it nailed - 6% total (at final) & 10% for inside conditioned space (especially for "balanced" systems where they have actual returns in each room) with maybe a max based on nominal airflow. Shoot to make it fair for smaller houses  to promote them maybe even go 8% for homes under 1200 SF. As for reporting, I think it should be both the % but also as Ted points out - actual leakage numbers 

RSS

Home Energy Pros

Home Energy Pros was founded by the developers of Home Energy Saver Pro (sponsored by the U.S. Department of Energy,) and brought to you in partnership with Home Energy magazine.

Latest Activity

Hal Skinner replied to Hal Skinner's discussion An example of what an RCC can do with no R- insulation in the walls.
"Mornin Brett. 90 to 85, yes a slight variance there.  Same ASTM test, different scientists,…"
55 minutes ago
Bret Curry replied to Hal Skinner's discussion An example of what an RCC can do with no R- insulation in the walls.
"Great information Hal. It appears the thermal emissivity in your test was .85 rather than .90. Are…"
1 hour ago
Juan Roca commented on Dale Stephens's blog post LED Lighting - Garage Door opener interference
"Hi,There is a real problem with remote controls and LED lights. However, there is a solution in the…"
8 hours ago
Profile IconJuan Roca and Elizabeth Coe joined Home Energy Pros
19 hours ago
Casey Gesell posted videos
19 hours ago
Gerald Shechter posted videos
19 hours ago
Hal Skinner replied to Hal Skinner's discussion An example of what an RCC can do with no R- insulation in the walls.
"Bret,  here are the 2 reports I referred…"
21 hours ago
Craig Foley shared George Kopf's discussion on Twitter
22 hours ago

© 2014   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service