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: 557

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

Dennis Heidner replied to Christopher Talarico's discussion Heating with Tankless Water Heater & Hydronic Air Handler vs. Gas Furnace
"Rinnai has application note on how to use their tankless hot water heater with a Rinnai water to…"
1 hour ago
Hal Skinner replied to Hal Skinner's discussion How much heat energy is lost through the floor of a house?
"I found the buildingscience article interesting.  Interesting that they noted the wet bottom…"
12 hours ago
Bud Poll replied to Hal Skinner's discussion How much heat energy is lost through the floor of a house?
"With conduction that ends at the bottom of the joists and convection that is naturally suppressed…"
13 hours ago
Hal Skinner replied to Hal Skinner's discussion How much heat energy is lost through the floor of a house?
"Good morning Bud, Took a quick look at the site and a couple others listed on the Yahoo…"
15 hours ago
Bud Poll replied to Hal Skinner's discussion How much heat energy is lost through the floor of a house?
"Hi Hal, Search "Basecalc basement heat loss".  From memory Canada (nrcan) has/had a…"
17 hours ago
Michael Dunseith posted photos
yesterday
Hal Skinner replied to Hal Skinner's discussion How much heat energy is lost through the floor of a house?
"II just remembered seeing a report by a federal adency, many years ago, that basically said …"
yesterday
Don Fitchett commented on Tom White's video
Thumbnail

Alliant Energy's PowerHouse TV: Sealing Leaky Ductwork

"Very educational. thanks for sharing Tom."
yesterday

© 2014   Created by Lawrence Berkeley National Laboratory.

Badges  |  Report an Issue  |  Terms of Service