Aug 272010

Wednesday, February 24, 2010

Well, I’ve been in my yurt for about 5 months now…

I know, I know…the construction articles stop at platform construction.  I’m gonna finish ‘em soon.  There are about 4 more construction articles to go and they are all already in the pipeline…be patient.

Anyway…after 5 months of yurt living, including the coldest part of the winter, I’ve got some observations on my radiant heat floor…and they apply to any radiant floor on a crawlspace, not just a yurt.

This radiant floor thing was new to me when I started my yurt.  I had done a lot of research on all the house systems, as this is the house I’ll live out my life in and I wanted to be happy with everything so I checked all my ideas very well before starting.

My criteria for the systems were:

They must be initially economical to purchase and install…economical, not cheap.  There IS a difference.

They must be economical to operate.  I live on a very limited income and monthly expenses must be kept to a minimum.

They must be durable.  Both for money and for convenience reasons I wanted systems that were “build and forget”, except for maintenance, as much as possible.

They must be efficient.  I don’t care how inexpensive to install and operate a system is, if it doesn’t do the job it costs way too much.

Based on those criteria I chose radiant floor heat as my heating system, despite the fact that I had never, to my knowledge, even been in a building with radiant floor heat, much less had to live with it.

I’ve gotta admit…if I had written this article in mid-December I would have been talking about what a poor heating choice I had made.  The first of the really cold (for here) weather had begun and two things were happening regarding heat, and both were bad.

First, I was COLD!  Nights in the upper 20’s outside temperature were giving me inside temps of about 53-55 degrees when I got up in the morning…not freezing certainly, but very uncomfortable.

Second, it was costing me a fortune in propane to get what little heat I had.  I was going through 125-150 gallons of propane a month to heat the 700 square foot yurt, run a gas dryer twice a week, and cook for just me.

I was very disappointed…and wondering how I was going to afford to heat the place when temps dropped more.

I went back through my research on radiant floors, and took another look at my installation to see what might be wrong, and discovered a fatal flaw in my approach.

I had acted like my radiant floor was a heater, not a heating system!

I tend to be a bit lazy when I can get away with it, and my laziness had caused me to only do half a job.

The radiant floor itself was properly installed…but the floor was a heater, not a heating system.

Because I had mostly finished the yurt in mid-September, I drug my feet on the final work…including turning the floor heater into a radiant floor heating system.  The floor joists were not insulated, the floor joists were still open to the elements, and the yurt had no underpinning, standing on its posts like a stilt house on some Pacific island beach.

Well, DOH!!!  Pacific island beaches don’t have temps in the teens and 20’s!

The pex tubing embedded in my sub-floor, along with the water heater, makes my floor a heater.  The following three additional items make my floor an efficient heating system…finally.

1.)   Insulate the floor joists.  Fortunately, when I ran the plumbing and electrical for the yurt, I had consistently drilled through the joists high up so the heat from the floor would keep the plumbing from freezing in cold weather.  This left plenty of room for R-30 bat insulation between the joists and under the plumbing and electrical, keeping them even warmer.  As an added benefit, this will SLIGHTLY lower your hot water costs.  Since the cold water lines are kept so warm, it takes less hot water to temper the water for a nice, hot shower.

2.)  Cover the bottom of your floor system with an airproof material stretched and stapled to the bottom of the floor joists.  I think Tyvek is probably the best material to use but any air-proof material will do the trick, even roofing tar paper.  Be sure you overlap the edges of the material and attach it to the joists every 8 inches or so to avoid air infiltration through the gaps.  This will help insulate your floor two ways…it will prevent the wind from carrying away heat from little nooks and crannies around your bat insulation and joists, and it will act as a barrier to critters that like to burrow into bat insulation, like rodents, to make their homes.

3.)  Underpin/skirt your foundation as a further cold air barrier.  Depending on how you plan to finish the house below floor level, here are two suggested methods.

If, like me, you intend to build a walkway all the way around your yurt, consider having the good looking finished underpinning at the outer edge of the walkway rather than at the outer floor edge (I plan to face-rock the outside of the walkway after I build it) and wrap the outside of the yurt edge with Tyvek stapled to the legs.  If you are going to build a walkway like I am there is no need to spend money on underpinning looks.  Then, after building the walkway, put whatever surface on the walkway underpinning you want so it looks good…as I said, I’m going to face-rock mine.

If you aren’t going to build a walkway, or if the walkway is going to be open underneath, then still wrap the yurt underpinning in Tyvek for an almost windproof barrier and put your finish covering over the Tyvek.

Learn from my mistakes.  Make your radiant floor an efficient radiant floor heating system, not an inefficient, and expensive to operate, radiant floor heater.

Editor’s note:

All posts on JuicyMaters are meant to be discussions, not lectures.  Please use the comment box at the bottom of each post for questions and comments, or to suggest another way to do something related to that post.  My way of doing something is A way, not THE way.  Suggestions are welcome.

If you wander around JuicyMaters to areas other than yurts, the request for comments applies there as well, including the politics section.  Nothing there is moderated for content…all views are welcome.  Just use facts, not ad hominum attacks, and be polite. Rudeness and bad language are the only things that will get a post deleted.

Y’all enjoy JuicyMaters.  Tell your friends about it, and come back often, ya hear?

All about Bob the nutjob!

Bob is a N Georgia blogger, homesteader, yurt liver, self-sufficiency nutjob, pig farmer, political activist, politician baiter...and the best damn cook you know that doesn't make a living at it.He can be followed onTwitter. You can also "Like" our Facebook page.

  16 Responses to “Notes on a hydronic radiant floor”

Comments (16)
    …..yurt liver, I AM ALSO…political activist, politician baiter…YES YES…and the best… WORST cook you know that doesn’t …COULDN`T make a living at it.

    I very much appreciate your help with your write-up as I was planning floor heating for pending Ontario Yurt living…Scarey new life-style but exciting too..

  2. What are you using to heat the radiant floor? A hot water heater? what is the propane system you are using~~`brand name? Are you using water in the pex tubing or a mix?

    I live in Vermont in a yurt and have thought of using the woodstove to use a hydronic radiant system~ but having well insulated floors and adding area rugs in the winter helps keep the floors warm ~~its the ambient air temp that needs warming~ it got to -20 last winter and it was a mild winter,
    How was last winter for you


  3. Hi Corina…glad you stopped by.

    I use a tankless water heater…a Takagi-TK Jr. (bought from Pex Supply, the company that advertises in the sidebar. I bought 2 from them, one for the floor, one for the potable water) It feeds water through 750 feet of half inch pex tubing in the floor, circulated by a 1/4 HP inline pump. I run straight water, not a water/glycol mix, and have not had any problems. I fully expect to have to replace the pump every 5-8 years as it is a cast pump, not stainless steel and eventually the air in the water will cause rust, but that is a $70 or so maintenance item, far cheaper over a 20 year period than a stainless steel pump.

  4. I just want to say thanks…I am researching on living in a yurt. I enjoying your site learning from trial an errors of others. I live in NC
    thanks Carla

  5. Hi Carla…thanks for dropping by, and for the comments on the info here. Keep coming back…most of the posts here are yurt related even though there are 3 other categories. I can tell you from personal experience that yurt living rocks!

  6. Howdy Bob,I got your contact from Kim,at Pacific Yurts.Love your blog! Okay Bob …here’s the skinny.We live on Orcas island,Wa. Me,Wifey,and Kiddo{9yr old}. Were thinking yurts here.2, 16 ft. yurts with a common bathroom connecting the 2.These would mostly be used for sleeping.However,our daughter would most likely use hers more often as a place to hide out from adults.Ive come to a conclusion that radiant heating is a must for a yurt,with our long, cold,damp,windy,climate. My first question would be…..Do you think it would be a good idea to build on top of a slab on grade? Or would it be better to build on top of a raised platform?Im not concerned about having a deck,or walkway around the yurt. First of many questions. Thanks Bob enjoy the spring weather! Doc

  7. Hi Doc…Thanks for visiting.

    I’m away from the computer for a couple of days, cjearing land for my second yurt, and answering on my android, so this will be short…but I wanted to let you know I will answer a LOT more completely on Thursday evening…I just can’t write much on this tiny keyboard.

    Talk to you Thursday.

  8. So what was the answer to the slab/platform question? My husband and I are considering building a yurt in the mountains of NC in 2 years – radiant heat seems like a wonderful heating option for cold mountain winters. Thanks.

  9. Geeze Peg…thanks for the prod. I had totally forgotten to come back and answer that question.

    I’ve never been a fan of a slab on grade, but if the building site is flat it is probably best for appearance sake, though where water is going to go during heavy rains REALLY would need to be addressed.

    I personally like a crawlspace foundation for all housing in order to get as much of the plumbing as possible below floor level in case there is a leak. You can keep everything…water heater and supply lines…below the floor except what is stubbed up for attachment to fixtures.

    In the case of a yurt using a crawlspace foundation has an additional advantage. One of the only complaints new yurt livers have is the lack of space for storage. Getting accustomed to the smallish floor space PLUS adjusting for the round structure is a challenge and having a crawlspace for additional storage helps.

  10. There are some new insulating items on the horizon.

    For the tankless hot water heaters there is an electric model that modulates. That means the water passes through it, travels through the pex tubing and comes back to the tankless heater to be heated again. But the heater is smart and can sense how much more energy it needs to get the water heated back to the correct temp again. You may initially think that electric is not the way to go. But this is a pretty smart system if you have electric. Now, if you are really ambitious, there is a solar thermal system that also includes hot water storage. Pair this with a tankless system and you are in really good shape as long as you have created a system, insulating where necessary. If anyone would like information on the solar thermal system, please let me know.

  11. The insulating products are top secret. I will let you know more next week.

  12. Hey Bob,

    I’d be interested in info on the solar thermal system please. Also would you say that the workings of your yurt, are quiet. I realize that the outdoor sounds are more prominent but I’m wondering about the water system and heating system. I’m in the early stages of planning and costing a yurt.

    Thanks for your help,

  13. Hi Sharon…glad you stopped by JuicyMaters…keep coming back.

    If you’ll be a bit patient with me, around mid-January I’ll be adding an entire section to JuicyMaters that is basically the entire how-to of yurt living. Much of that info, but not all, is already here on JuicyMaters, but in a conversational, story-telling way, and leaves gaps. What is coming starts with answering the question “What kind of alternative housing style fits me best?” and goes through the legal aspects of building a non-traditional home, financial challenges, site selection, platform construction, kit erection, and finishing out the interior. It will be put together in a “just the facts, m’am” manner, a linear step-by-step how-to-yurt sort of thing. It will include financial considerations.

    Have a FANTASTIC day!

  14. Hi Jim…glad you stopped by. I’m always glad to have a new member join the JuicyMaters family. Keep coming back…there’s no telling what you might find here…LOL!

  15. Great Blog. I was just wondering, how much did the propane use go down once it was insulated?

  16. Hi UP…it cut my propane useage by between a third and a half. I was amazed that it made that much of a difference.


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