Energy Efficiency of conditioned crawlspace
Bubby07
| Posted in Energy Efficiency and Durability on
I think I am sold on why a crawlspace should be conditioned, especially in my area (Houston). However I’m not sure I understand the efficiency part, especially since I will have to heat/cool that space. It is a 4300 sq ft 2 story house (about a 2500 sq ft footprint) and the crawl space is abouit 4 ft. So is that a negligible heating/cooling cost (equipment and heating/cooling bills) compared to a vented space? How exactly do you compare the efficiency of one vs the other?
Thank you
-chris
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Replies
Chris,
There are at least two reasons why sealed crawl spaces save energy:
1. Sealing the perimeter of the crawl space to stop air leaks is usually more effective than trying to air seal the subfloor above the crawl space.
2. Most crawl spaces have ductwork in them. Bringing the ductwork inside the conditioned space of the home saves a tremendous amount of energy.
"Bringing the ductwork inside the conditioned space of the home saves a tremendous amount of energy."
Does it save more energy in the long run than the energy (and cost) required to heat and cool the crawl space?
Chris,
Yes. Advanced Energy in N.C. did a study showing that result. I should be able to dig up more details on the study if you need to see it.
I would absolutely love to see it. Thanks for your help Martin.
-chris
Chris,
http://www.advancedenergy.org/buildings/knowledge_library/crawl_spaces/pdfs/Closed%20Crawl%20Spaces%20Do%20Double%20Duty.pdf
I recently saw a presentation from Advanced Energy on a project they did in Arizona I believe. They actually acknowledged that there was a slight energy penalty in the winter time but general consensus is the energy savings the rest of the year and more importantly, the moisture control outweighs the minor winter energy penalty.
This is good stuff. Thank you all.
The bottom line is this: If you have HVAC ducting in the crawlspace (or attic), then you're already heating and cooling it.
So the only reasonable question is this: Do you want to pay to heat and cool uninsulated space? Penny wise and pound foolish, as the saying goes.
Robert
Good point. So are conditioned spaces starting to catch on? I certainly don't see a whole lot of it around here (maybe I'm not looking in the right places?)....or is it still something only written about but rarely done.
Conditioned attics and crawlspaces are becoming common in the more energy efficient homes in North Texas.
I think the practice is like a band-aid though.
Mechanical should have never been in attics and crawlspaces.
Best practice is to get the mechanicals out of attics and crawlspaces.
This Texas home eliminated the crawl space entirely:
http://www.angelstarcreations.com/special/buildings_files/kettle.jpg