Back in September many of you provided excellent info regarding my attempts to do a radiant ceiling heating/cooling system in a remodel. As of now we have abandoned this idea completely. The plan is to do radiant floor heat and possibly add a small separate cooling system to handle the master suite.
The house is now down to the studs and my contractor has talked to several HVAC subs, each of whom is recommending a different way of installing the system. I have been away and not able to meet with the subs as of now. The house is 60 years old with either full height basement or crawl space under all flooring. The basement joists are 12" and the crawl space joists are 8". Before removing the existing hardwood floors, the living room/dining room and kitchen had 9'4" ceilings and the bedroom wing had 8'1" ceilings.
We do not want to lose more than 1" of bedroom wing height and want an engineered hardwood floor except for kitchen and baths, so doing a gypcrete floor is out. The two solutions that have been proposed are using an Uponor type floor with precut channels for PEX and an aluminum radiator sheet under it that will sit on top of the subfloor (an addition of about 5/8" to the total floor) or an Ultra-fin installation below the subfloor that is then insulated from below. Apparently, there is only one mfg. for the Ultra Fin because of patents. We would also insulate the the Uponor style from below. I didn't look at Warmboard yet.
I would appreciate any suggestions regarding these two choices or some other choice not mentioned. I did look at a different forum that had comments from 2004 regarding the Ultra Fin system not performing well if the area beneath it was cold. I'm also not crazy about the 180 degree temp I think the water needs to be.
Separately, I want to thank Skippedover for some recent general advice regarding choice of subs to use.
Be sure your contractor does a heat loss for each room, tubing lay-out & required fluid temperature, designed for your location, & your flooring. Backside insulation is a must (as many have found out).
I would do the pre-cut typw floor with pex tubing. I would install a high efficiency fully modulating boiler (Buderus, Weil Mclain phd) with two circuits one for radiant heat and for domestic hot water for the addition. In-floor radiant heat does not require high temps to work. If your feet are warm you will be warm. The boiler would only use the amount of fuel required for the load. and domestic hot water takes priority. I would use a ductless style system for your air-conditiong. You could also do the heating and domestic hot water via a solar system. There is a substantial up front cost but the savings would be tremendous.
using underfloor type will require higher water temps to compensate for the insulation (plywood) between the floor and the heat source. I can tell you that I have installed the viega system in my home, similiar to the uponor, (actually I think the panels are the same), and I am very happy with it. I used seven inch spacing on my own home which gives me lower water temps, but requires more tubing. it is available in seven and ten inch spacing. My water temps generally run in the mid nineties here in pa. Installation is simple, although it takes a little bit of time, and i have about eight hundred square feet done so far, converting my home from baseboard to radiant as I renovate, utilizing a mixing station connected to my oil fired boiler with no problems.
knowing what type of floooring you want to utilize is important, as each flooring type has a different r value, which needs to be used in estimating load. the higher the r value, the higher the water temps. I used a floating, engineered floor made out of eucalyptus with a firm rubber pad underneath for a total r value of less than two. This gives me really good heat transfer to my space. I too have crawl spaces under the rooms. for those areas you want to carpet, choose wisely, as carpet people have no idea, in general, of r values of their product. when i looked at flooring, I used the viega installation manual to identify r values, as they have a list of various finishes and r values in the booklet. on their site, they also offer free sizing software which also does component takeoff for you. the total floor height sacrificed is one half inch. I utilized regular half inch plywood to fill the spaces i didnt want heated, such as under my island in the kitchen, and under specific cabinet locations that dont require heat, or it would be undesirable such as under the wine rack on the end of the island.
There is no better way to heat the space than radiant. Ultra-fin is an excellent product, insulation below it is a must. Any time one can get away from 180 F is a plus for many reasons. Accurate heat loss calculations are a must. You may want to consider baseboard heating, it is simple , looks have improved and should reduce your installed costs. As far as cooling, mini splits are definately a very efficient way to cool a small space.
i installed radiant in my office ,family room,kitchen & living room
i used the product rehau product raised floor only 5/8 of a inch
and i used 8" centers and 110 degree water and my finish floor is
endenered ??????? hardwood
Thanks for the responses, which, in turn, generate some additional questions and issues.
First, does anyone know why the Ultra Fin water temp seems to be so high? Virtually all other radiant recommendations are for much lower temps, some as low as 80F.
Second, we are planning to use the existing 60 year old subfloor, which is not plywood. I'm not at the house now, but I would guess it is 1x6 planks, and many of them are not butted along the lengths, so there are many air gaps. How much of a problem do you think this is, given that we plan to insulate very heavily under the joists regardless if we go for an above or below subfloor install.
FYI the engineered floor is 3/4" thick with 5/32 oak over 19/32 10-ply plywood. It is a thing of beauty, but I don't know the R-value.
underfloor, or staple up as it is sometimes called, has to be hot enough to radiate throught your insulation, ie, the 1x6's, so hotter water temps are required. in addition, the tube spacing matters and figures into water temps, and with your layout, spacing ay be limited to say twelve inches on center as opposed to say seven for overfloor. less tubing means higher water temps to hit the btu output required.
As far as your flooring choice, make sure your installer knows this prior to selecting a system. it needs to be figured in the load calcs, or at the very least, estimated. The more you do now, the better the system will work when installed. why are you using the plywood? is it to level the floor? if so, put it under the radiant floor panels for less r value in the finished product.
Thanks for earlier responses. Went to ASHRAE on a quest for the best and concluded that the Raupanel system made the most sense for me. Only adds 5/8" to the subfloor and seems beautifully engineered. Some of the other systems looked pretty cheesie.
Ubeill, how was your experience with Rehau, and what did it cost? We are in a very expensive labor market, so ours will probably be more. Just curious.
Anyone else with Raupanel experience? Any other thoughts on what to put in? We rejected under floor installations for a variety of reasons.
installed floor beginning 2 years ago ,was very positive install.
install costs would be less(this install was free because it was my house) but product is some want expensive ,but works great with water temperatures, only 5/8/" high & doesn,t raise floor alot
Rehau makes a very good product. I have never used their panel before do to the expense of them. The panels limit the tube spacing to 8" with 3/8" tubing. Make sure the calculations are right in each room. If you are installing a wood engineered flooring directly over the Raupanel, several items must be addressed. The temperature of the radiant loop and the obvious,no nails or staples into tubing. 5/8" is not very thick to nail into. I prefer to use the light weight Thermafloor over the tubing , but it adds height to the floor which means all doors need to be undercut. The advantage is a better thermal mass,tube spacing can be designed to match the room, and tubing does not need to be installed in dead zones.
Originally Posted by dmlederman
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