VersaTherm radiant panels

a9876

Does anyone have any experience with VersaTherm radiant panels? What is your opinion about them? We are considering radiant heat over slab with engineered wood or wood floors. We would like to have appropriate insulation with minimal floor raise. Would you suggest any other options for this application?

Gordy

I will say that galvanized plates do not have the conductivity that aluminum plates of the extruded variety do. There for your supply water temps would be higher, and or heat output would be less. I would like to see some output charts.

hot_rod

If you want thin, the Uponor or Viega system is about 1/2" thick. It uses a 5/16" pex tube.
The Roth with 3/8 tube is about version is 3/4"thick.

I have not seen any manufactured product less than 1/2". Other wise underfloor systems are inn option if you have access.

I do prefer the dry systems that use actual plywood, not a big fan of particleboard types.

Sunboard is another brand to look at they have several options including a graphite covered furniture grade plywood core version.

1PI

Check out Warmboard –R , the thickness is about 13/16th and it installs directly over a slab with a thin 6 min polyethylene plastic under the panel.
Due to the location of the aluminum top skin the panels conduct the heat extremely well without insulation. The hardwood can nail directly over the panels. Attached is an actual thermal image that I shot with hardwood , directly over slab.
Thanks PI

Rich_49

Warmboard S & R are without a doubt the finest 12" oc products available . Unfortunately they are 12" products and cannot match a similar product with an *" oc configuration . The OP would be better served in this instance by looking at what Hot Rod mentioned , Sunboard .

http://www.sunboardpanel.com/1_2_x_3_4_GOLD_Particle_Info_sheet_030614.pdf

Before the debate begins . Thicker aluminum (mass) offers no real measurable benefit , more mass takes longer to heat up before providing heat to the space to be heated . There is a bit more storage in that case but in this particular application without insulation can actually be a drawback , downward heat loss . Lower water temps are a given for like output and price difference may or may not be a factor for this poster .

My real thought to heat the space is radiant ceiling . Would that be difficult in this persons case ? No idea , jsut a thought . maybe others will chime in on that possibility . Downward loss and the fact that a colder slab exists actually makes this preferable and quite possibly easier and less costly . Hot goes to cold always . The slab taking into account the ground temp below ( basically steady temp) will always accept the energy while suffering less downward losses . Heating at the floor plane would increase the Delta promoting more downward loss to the soil . The sunfoam also has a slight R Value and a graphite coating , much more conductive than aluminum . That's why the latest light bulbs are using graphite for the element . Sheetrock also has a lower R value than your typical floor with the exception of tile or stone .

http://www.sunboardpanel.com/SunFoam_-_info_03172014.pdf

a9876

Thank you, everyone, for taking your time to let me know about possible options. Warmboard was the first option we looked at as it seems like good quality product, though, Roth panels have better R-value as they are made with insulation. The chalenge with Roth - couldn't get sample to see how it looks like, if it is too soft, and was uncertain about proper installation over slab. We can't do radiant ceiling. Sunboard is made with insulation, which is great, though, I think it requires overpoor, which probably will add additional hight. This week, I learned about VersaTherm. It has lower R-value than Roth (3 vs. 3.7), though seems easier to install and sturdier. However, I have not heard of anyone who had experience with it, which makes me think something maybe wrong, and, again, I can't see what it is as no samples available. Would you agree with my comments? Would you have any other comments or suggestions?

Rich_49

Sunboard does not manufacture any product that gets installed with any type of overpour . The Sunfoam product would be the closest thing to resembling that but is made to have Hardibacker attached then thinset and tile . It is also of a thickness that when used next to or abutting hardwood both finish floor heights will be the same without transition height . Sunboard readily offers the spec on compressive strength .

hot_rod

I'd be glad to send you a Roth sample, I have a box or so left over.

Can the VersaTherm be glued down to the slab. Unless you have a laser flat slab, I don't think you would float them? the hardwood will want a fairly stable underlayment.

The Roth can be glued to wood or concrete with the appropriate adhesive, if that matters. Since it is over concrete the hardwood will need to float.

a9876

Thank you, hot rod, it was very nice of you to offer a sample. As I was just about to coordinate with you, I got a sampe from Roth' sales division. After some time they ware able to obtain the sample. The panel looks good- quite sturdy and seems to have good quality. We plan to put floating engineered floor over it. Though, since we will need to raise doors, I would like to make sure we consider other options in case changes need to be made in the future, i.e. change to hardwood. I heard that some like to put plywood on pannel and nail hardwood to plywood. Would you see any issues with this? I don't think plywood has high R value and I would think it should be ok in terms of heat going through, though, I may be wrong. If having plywood over Roth panels is ok, maybe we shoud put it between Roth and engineered so there is no need to adjust doors in the future.

Rich_49

3/4" Hardwood (most species) right over the panels has an R Value of about .6 while the same floor with the plywood added equals 1.58 R Value .
The room has a SWT requirement of 100* with the 1.58 R and with the .6 R SWT is 89* .

hot_rod

I don't think you could just float plywood over the Roth, or any panel. You would need to fasten it down through the Roth panel and into the concrete. That would be a big job.

If not the plywood, and the hardwood on it would just "potato chip"

The plywood would add more resistance for the heat energy to travel through. It would spread the heat out across the flooring better, but cost you increased temperature and slower response.

I'd look for a floating product, skip the additional layer.

Paul Pollets

Original slabs usually have no insulation under them. R-10 is minimum for a retrofit (2") under the panels with our state code. Have you considered your water loop temps without insulation?

SWEI

Walls? Ceilings?

Gordy

Ceilings are a most missed, or ruled out opportunity. Build up can be as little, as a floor overlay with out the threshold, and door issues, and the insulation is already there usually. Plus it works. You can have a higher btu output per square foot because ceiling panels can have higher surface temps than floors if the need is there. Ideally though run low as you can go water temps though. Forget everything you think you understand about heat rising.

jonny88

@Gordy when running tubing in ceilings is it hard to keep the system from getting airbound?Would love to try it out on a job coming up.Thanks.

Gordy

No different than a floor, or walls. Velocity. You can have manifolds in the basement, and purge the air from the loops.

SWEI

..and no more fights with the interior designer about floor coverings or wall space.

They do have to make a hard commitment on the ceiling cans. Changes there are no cheap. Think track...

jonny88

Thank you guys.

a9876

@Paul Pollets you are right, we have no insulation in our slab. I also wanted insulation with at least R-10. I heard about need for even higher R-19. But we want to find the best compromise between insulation and floor hight. I was hesitant about R-4.5 but heard from some guys that it is enough to redirect heat from slab to floor. We don't know whater loop temps yet but will look into it. What would be acceptable temps requirements for R-15 Insulation? We may be able to add some perimeter insulation, which, hopefully will help.
@hot rod There would be a need to screw plywood through panels to concrete, which I am concerned, will also do some damage to concrete. We probably will skip plywood.

SWEI

Adding floor heat to an uninsulated slab on grade is a battle I no longer choose to fight. Walls! Ceilings!

Gordy

It will work with unintended consequences. Those are slowed response time, higher supply water temperatures, fly wheeling which is the concrete floor will soak up the heat also, and release it in a delayed fashion causing room over shoot. In other words the room will keep heating after the t stat is satisfied. Last but probably most important is increased energy bills.

There are controls at added costs that can curb some of these reactions.

In a properly installed RH system the goal is lowest possible water temps, quick response, and comfort. Unless your house is poorly insulated do not expect warm floors. Neutral should be the goal.

hot_rod

SWEI said:

Adding floor heat to an uninsulated slab on grade is a battle I no longer choose to fight. Walls! Ceilings!

True that, but the load of the room is the same regardless of where the emitters are. The uninsulated slab becomes a hard to control flywheel, is all.

There were some studies years ago as to how far that energy would travel out in an uninsulated slab, or without edge insulation. I think Mr Pex was involved in that somehow. And there was a time when some radiant manufacturers suggested only insulating the perimeter of a slab on grade, also.

Reminds me of those deep sand bed radiant systems the Wisconsin boys install, saturate the sand with solar thermal all summer and let 'er rip

SWEI

Remove the emitters from the slab and conductive losses go way down. Throw down some nice wool area rugs and everything gets nicer...

RobG

And god forbid you have a high water table or your home is built on a slab of stone. Hot goes to cold and you have to heat the cold before the radiant will go up.

a9876

The slub is not insulated. Though, Roth panels are made with insulation of R-4.5 (i mistyped number in one of previous posts). We may be able to add also insulation on perimeter. Would you still suggest to put additional insulation under the panels?

Gordy

R 1 is 100% better than R 0. So with that being said if you can use the Roth panels by all means do so that would be 450% more r value than R 0. I love how percentages can make meager improvements sound astounding.

hot_rod

I'm not sure how that R number is arrived at with the Roth Panel. They only have about 1/4" of foam under the tube and the entire panel is only 3/4". Generally to best foam is considered R-5 per inch.

Bottom line is how badly you want warm floors Without a good R value under and around the slab you will have some downward loss. $$ wise it may or may not be worth the operating cost.

On the plus side, basements are not generally a high load room, if the upstairs is warm. Also with radiant you will probably not need to run 70F to be comfortable. It may also depend on how you plan on using the room and the amount of furnishings that would be over a radiant panel.

I would add, after having lived with several for two winters now, I really like the panel radiators in my bedroom. I reach out from under the covers 1/2 hour before we get up, crank up the TRV, feel the radiant warmth, and set it back down when we are up and at 'em. They are incredibly easy to retrofit.

a9876

@hot rod we heard the advice for radiators as well. I am concerned that they will limit placement of furniture. But we still keep it in mind.
In terms of how rooms are used, the rooms are on ground level of kind of split level house. We have forced air but warm air raises to higher levels and ground level gets cooler. Also, forced air makes air very dry. I was hoping radiant would help to make lower level warmer. Also, with availability of radiant, we could lower forced air use and, hopefully, to make air less dry. Maybe with two sources of heat we could keep radiant at lower temperature as radiant is not the only heat source?
Another concern with Roth we have- will they deteriorate with time as they are made from softer material making sagging floors?

hot_rod

If you plan on spending a lot of time on the slab, or kids plying on the floor, radiant floors really are the ultimate, in my experience.

I've lived in apartments with carpet, even thick shag! over concrete and it never felt as comfortable as a radiantly heated floors. If you spend winters with wool socks, or shoes on in your home it may not matter to have warmed floors?

How large is the space? after a load calc you could determine how much energy is needed, then convert that to monthly fuel cost and see if it is in the budget.

You are a bit restricted by the uninsulated slab, but there are many un-insulated or poorly insulated (think Insultarp) slabs running across the US. I know suppliers and reps that still sell truckloads of Insultarp even for slab on grade installations! Fuel mileage will vary based on the type and amount of underslab insulation.

I believe the foam of the Roth panel will probably last your lifetime. They say that type of foam (coffee cups) is almost impossible to breakdown in the landfills. Some solvents go after foam aggressively, buy water, dirt or Pepsi, properly not.

Gordy

Since you already have Forced air. How are you planning on heating the water for the radiant?

a9876

@Gordy We are planning to install a boiler.