https://www.energyvanguard.com/blog/5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space/ Building science knowledge, HVAC design, & fun Tue, 25 Oct 2022 13:33:51 +0000 hourly 1 https://wordpress.org/?v=6.6.2 https://www.energyvanguard.com/blog/5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space/#comment-5980 Sat, 27 Jul 2013 00:04:36 +0000 http://energyvanguard.flywheelsites.com/?blog_post=5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space#comment-5980 Cameron T.
Cameron T.: Yeah, keeping the heat out of the attic to start with is a great strategy if you’re not going to encapsulate the attic. I wrote about shingle temperature and attic ventilation for Green Building Advisor a few weeks ago, and there’s some good info there about this topic. 
 
Anthony H.: Yeah, I’ve seen a lot of attic HVAC systems like you describe. It’s nice that things are changing a bit, at least with some contractors, though. 
 
Ryan S.: That’s a wonderful resource! Here’s a clickable link:  
 
Steve W.: Yes, that house had a transfer grille through the floor so the air put into the crawl space could make its way back into the house and through HVAC system. That’s how Joe Lstiburek did it in his house, too.  
 
 

]]> https://www.energyvanguard.com/blog/5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space/#comment-5979 Fri, 26 Jul 2013 23:41:40 +0000 http://energyvanguard.flywheelsites.com/?blog_post=5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space#comment-5979 Allison, 

Allison, 
 
Thanks for making time to pen (?) yet another informative and entertaining article. A twe-fer, if you will. 
 
Regarding the linked article, “Beautiful Duct System…”, there is a photo of a system in an encapsulated crawl space showing provisions for supply off one of the trunk lines. We’re any special provisions made for return air? 
 
I encapsulated my 2002 crawl space a few years back after I discovered a 4″ supply line had been installed vertically from the attic distribution system. The floor above the crawl was so well sealed, there was no air flow from the 4″ duct unless the closet crawl space access was open and I finally installed a return grill there. 
 
Warm(er) hardwood floors in the heating season are wonderful and no discernable effect on heating costs. Would have been hard to notice unless it was dramatic. 
 
Let me know about return air provisions. 
 
All the best.

]]> https://www.energyvanguard.com/blog/5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space/#comment-5978 Fri, 26 Jul 2013 22:05:27 +0000 http://energyvanguard.flywheelsites.com/?blog_post=5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space#comment-5978 We (Earth Advantage) worked
We (Earth Advantage) worked with NEEA to create ducts inside dot org: http://ductsinside.org/ 
There are lots of great (free) downloadable documents that cover these same concepts with greater detail for builders and design teams.

]]> https://www.energyvanguard.com/blog/5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space/#comment-5977 Fri, 26 Jul 2013 18:14:35 +0000 http://energyvanguard.flywheelsites.com/?blog_post=5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space#comment-5977 Here in SE PA there are large
Here in SE PA there are large numbers of new (and not so new) homes with the second HVAC system in the attic outside the thermal envelope. Local code officials require both the HVAC unit and all ductwork to be above the insulation on the ceiling below. Often the equipment platform is not raised to allow full insulation depth and the flex duct is sagging between supports after leaving the body of he “ductopus”. Lousy design and installation is OK, as long as you can see the entire system – so how do they allow ducts between floors and inside walls? 
 
However, there are good local HVAC contractors. Recent new home duct testing for single systems, 2400 sq ft, low 20’s CFM25. Larger 5500 sq ft with 2 systems and total combined duct leakage of 54 CFM25.

]]> https://www.energyvanguard.com/blog/5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space/#comment-5976 Fri, 26 Jul 2013 17:48:43 +0000 http://energyvanguard.flywheelsites.com/?blog_post=5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space#comment-5976 With existing homes, many
With existing homes, many times it’s just not possible to get ducts out of the attic without considerable expense and mess. Therefore either reflective roofing (cool roof) or cathedralized insulation are the sane choices here. My experience with reflective roofing on my own pad has been positive; attic temperatures seldom run higher than outdoor ambient temperatures, and a/c supply air temperatures show little gain from plenum to most remote supply air register. House can be maintained at a 75 degree setpoint on 1st stage on a 100 degree day with ease. 
 
For new construction, ducts in attics should be completely eliminated. There’s no excuse to not accomodate them within conditioned space, but it’s hard to buck the tide in this area. It doesn’t get prospective home buyers to sign contracts, for the most part, so the ducts get thrown into the attic to make way for granite countertops and commercial range hoods.

]]> https://www.energyvanguard.com/blog/5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space/#comment-5975 Fri, 26 Jul 2013 16:28:08 +0000 http://energyvanguard.flywheelsites.com/?blog_post=5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space#comment-5975 geoff h.:
geoff h.: Yes, that issue has come up before in comments to our blog. John Tooley even commented about it here. I’ve threatened to write an article about that issue and haven’t gotten around to it yet. Thanks for the reminder! 
 

]]> https://www.energyvanguard.com/blog/5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space/#comment-5974 Fri, 26 Jul 2013 16:22:22 +0000 http://energyvanguard.flywheelsites.com/?blog_post=5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space#comment-5974 Covering ducts with blown
Covering ducts with blown insulation can have unintended consequences in hot/humid climates. Even properly insulated ducts can start to sweat & drip causing water damage and ‘microbial growth.’

]]> https://www.energyvanguard.com/blog/5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space/#comment-5973 Fri, 26 Jul 2013 15:38:26 +0000 http://energyvanguard.flywheelsites.com/?blog_post=5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space#comment-5973 Don P.:
Don P.: Yes, I should have mentioned the issue of existing homes vs. new homes initially, and your comment spurred me to add that to the article. Thanks, Don.

]]> https://www.energyvanguard.com/blog/5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space/#comment-5972 Fri, 26 Jul 2013 10:31:18 +0000 http://energyvanguard.flywheelsites.com/?blog_post=5-good-ways-1-bad-way-to-get-your-ducts-inside-conditioned-space#comment-5972 Very well done and straight
Very well done and straight to the point! 
However, to change the location of existing duct work can be very difficult and expensive. Many times just sealing the existing ducts and adding enough blown in fiberglass insulation to cover them is a better value.

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