Insulating hot water heat supply lines
We had an addition build onto what used to be our camp in the Adirondacks. The addition has enabled us to now use this as our home. The new construction has a basement and a new boiler. The existing structure has a crawl space that is skirted and insulated. I realize that there needs to be some additional tightening up underneath and will do that in the spring. In the basement, copper was used for the baseboard heat, the crawl space utilized Pex type supply. The basement is nice and warm and the crawl is cool. Realizing that there will be many yards of pex tubes running underneath, is it OK to try to insulate these so that heat is retained in the supply line and not lost by exposure in the cold area? Would the use of the foam insulating tubes and/or wrapping them with fiberglass insulation, provide an adequate payback? Should these lines be left un-covered? There has been glycol added due to our extremely cold conditions we experience (like this morning). With the cost of propane being what it is, I am interested is using as little as possible. We have “tweeked” the “set back” thermostats and use a woodstove and are comfortable inside. I have not been able to find any info concerning this subject – any advise would be welcome. Thanks
Replies
Does your potable water piping run in that same crawler?
If so I would not insulate the heating lines as the radiant heat will help keep the potable water lines from freezing.
If not I would use foam, as fiberglass is better for rigid pipe.
Rough calcs here, but every 3/4" of thickness comes out to an R-4 equivalent.
Thanks for the info. The potable water runs over 4 feet deep from the well casing into the warm basement. All potable waterlines are either in the basement, or through warm walls and soffits. Both hot and cold are insulated to retain heat and eliminate condensation. Concerning the hot water heat lines. I figured that the heat lost in transmission in a cold crawler would be better used inside. I was unsure if there was a danger in covering them. There appear to be a couple of kinds of pipe insulation. The Home Depot gray foam type (cheap) and the higher density type - obviously more expensive. Looks like I have my "mole" work cut out for me.
No danger in covering them. Try several different types of insulation to see what works for your situation -- what works in theory often sucks in practice when you're dealing with all the obstructions (and wretched working conditions). Keep in mind that you don't have to cover every inch of the PEX (given that there's glycol in the system), it's just that the more you can cover the less heat loss you'll have.
The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith
Thanks Dan - I think the hardest part is getting excited about the "crawl". My first step is going to install some lights to try to remove some of the creepiness.
Yeah, and spend some time cleaning up the crawl -- remove rocks and debris and level off the high spots. Put down plastic if it isn't down already. Especially clear yourself some "highways" to get to the various quadrants of the crawl.
The modern conservative is engaged in one of man's oldest exercises in moral philosophy; that is, the search for a superior moral justification for selfishness. -John Kenneth Galbraith
Excellent advice - we've owned this place for 19 years - I know it intimately. Years ago the plastic went down before the floor insulation went up. Where our new addition attached to the existing, was the absolute lowest spot in the entire place (8" from ground to the bottom of the floor joist). I personally back filled from that area and we could hold a dance for short people now.
I went to the "dollar store" and bought a bunch of the foam water noodles that kids play with. Make sure they have the hole in them and slit em open and fit over the pex.
cleaver idea - Thanks
But not insulating the radiant heat piping is a poor approach to keeping the potable water line warm ... in general. Why don't we simply heat and cool our atmosphere so that we don't need to heat/cool our homes. That's an extreme, but relatively speaking, that is what you suggest.
If not I would use foam, as fiberglass is better for rigid pipe.
What are you trying to say?? Are you suggesting foam or fiberglass?
Every 3/4" of what comes out to R-4?
Could you clarify? Either I'm missing the obvious or you've talked in tongues (honestly it could be either way).
He stated that his crawler was sealed with insulation , or something along those lines, but I wasn't sure if it was "conditioned". that's why I made the comment about not using insulation. If it was not sealed then I agree about heat just going out to the atmosphere.
Foam rubber pipe insulation is better for pex as pex is rarely ever in a straight line & fiberglass does not bend very well.
The R-4 rating is the average per 3/4" for foam rubber style insulation. Fiberglass usualy has a higher rating per thickness.
Hope that cleared up my post.
Yeah, misread a bit. And I didn't know you were talking fiberglass pipe insulation (vs. simple batts) ... duh.
Easka,
You should probably check out this article:
http://www.buildingscience.com/documents/insights/bsi-009-new-light-in-crawlspaces
This guy is pretty much the authority on all things building-envelope related. I know it's not directly related to your question but as long as you're messing around in the crawlspace it might be a good time to make sure everything's done right...
Thanks for the article. I printed it last night and read it this morning. Lots of "science" to understand, but basically, I get it. It makes sense and I believe that I had heard about the potential problem with insulation several years ago. I have not experienced any problems with the rafters as every trip I make under the building is also an exploratory of sorts. I like the concept and the idea of spraying on the H.D. foam as it would not only seal the wood, but would also encapsulate the hot water heat lines as well - 2 issues solved. The underside of the existing is about 1200 sq ft which I'm sure would be a quick 3 grand or more...however, in the long haul it may be worth it. I'm going to send a copy to an acquaintance who is a Code's Officer. He has lots of years in cold weather construction - I'd like his take too. Thanks again - very good article.
I misread part of the post. These are heating hot water piping. IMO ... Yes, always insulate them. Helps ensure the Btus get where you want them to be, not just 'under the house'.