LVP Over Hydronic Floor Heating

sniz

I recently installed electrical floor heating in a bathroom and I can set the temp to 90+ and it gets nice in there on the tile.

My plan in our new house is to put radiant hydronic floor heat throughout with mostly LVP on top and buying those panels where you can put the pex in grooves. Most LVP can only accept 85 degree tops. When I set our bathroom to 85 it's not that warm. How will this heat my entire house?

This project is a ton of money but I have doubts about it's actual heating ability. We will be putting in good insulation and redundant heating with a fireplace insert.

Can someone confirm they have used hydronic floor heat over LVP and it's kept their house warm in subzero temps outside? Where I am it get's into the teens fahrenheit often but every once in a while it's negative.

Thanks in advance!

hot_rod

85 floor temperature would be excessively hot. Probably too hot to walk on in bare feet. 82F is about the most you would run for a comfortable floor.

82F floor temperature would output around 24 btu/ sq ft.
So first step would be to determine how much heat the rooms need and see if radiant is a possibility.

In some cases the radiant alone will not cover the heat load, then you need supplemental heat. A room by room heat load calculation should be performed for all radiant installations.

There are brands of vinyl that are radiant compatible, check with the manufacturers of the products you are considering.

sniz

Thanks @hot_rod for the info.

So when I set my thermostat in our bathroom we just put in electric heat to 90, what is that referring too? It's a schluter system and I just assumed that the temp I set it too was the temp the floor would be.

This is just confusing to me so I'm trying to understand.

hot_rod

Most wall thermostats read air temperature. If you have a radiant specific control it could be reading floor temperature. And some radiant T-stats read both air temperature and floor temperature.

90° would be a very high setting for an air temperature reading. You may have a control watching the floor surface temperature only?

But I doubt you want either the air or floor at 90?

Sometimes t-stats get cranked way up if the system cannot reach or keep up with the desired temperature, either room air or floor temperature.

Is the electric floor heat the only heat in that room? In some cases bathrooms do not have enough floor area to heat with just radiant. A room with two outside walls perhaps?

Does the room maintain the temperature you want? How warm is the floor surface on the coldest day?

Sal Santamaura

I think the most interesting aspect of this thread is unrelated to sniz's direct radiant floor heat compatibility question. Rather, Dan's post years back, in which he showed a picture of a water fountain next to a Dasani bottled water dispenser, came to mind. His point was that if bottles of water could be sold in that situation, marketing radiant heat should not be impossible.

The reason I though of that was use of the term "LVP." Not too long ago, marketers were denigrating vinyl flooring while pushing other, more expensive alternatives. Now, having merely re-formatted the stuff from sheets into "planks," it qualifies as "luxury." Hillarious.

sniz

@hot_rod - Thanks for the reply.

Yes, that is the only heat in that bathroom. I put 2 floor sensors in when I installed the electric floor heating and tiled porcelain tile over the uncoupling membrane from Schluter.

It has one outside wall where the shower/tub is.

It gets nice a toasty in there when its set to 85+ and stays warm. The floor is definitely warm, not hot though. The temp stays at 70 as a default so the room never really gets cold. We haven't had any real temps below 40f yet so no winter cold days to gauge yet.

I'm just trying this floor heating out to see if our new construction will be worth installing a hydronic system. We did have someone do a manual j on the whole house and he suggested it would be just fine save for one room with vaulted ceiling and lots of windows. We plan on putting a fireplace insert in that room. Aside from that we don't plan any additional heat in any other rooms and my hope is that based on his calcs we should be OK.

But, testing this electric heat in a small room just had me asking questions to see if anyone else has done LVP over hydronic floor heating (sandwich method) and if it's worked for them. I"m struggling cause I don't feel too confident when I set the temp in that bathroom to 85 and it seems just enough to keep the room warm.

@Sal Santamaura - I don't get your point. Are you saying floor heating is a sales gimmick?

hot_rod

sniz said:

@hot_rod - Thanks for the reply.

Yes, that is the only heat in that bathroom. I put 2 floor sensors in when I installed the electric floor heating and tiled porcelain tile over the uncoupling membrane from Schluter.

It has one outside wall where the shower/tub is.

It gets nice a toasty in there when its set to 85+ and stays warm. The floor is definitely warm, not hot though. The temp stays at 70 as a default so the room never really gets cold. We haven't had any real temps below 40f yet so no winter cold days to gauge yet.

I'm just trying this floor heating out to see if our new construction will be worth installing a hydronic system. We did have someone do a manual j on the whole house and he suggested it would be just fine save for one room with vaulted ceiling and lots of windows. We plan on putting a fireplace insert in that room. Aside from that we don't plan any additional heat in any other rooms and my hope is that based on his calcs we should be OK.

But, testing this electric heat in a small room just had me asking questions to see if anyone else has done LVP over hydronic floor heating (sandwich method) and if it's worked for them. I"m struggling cause I don't feel too confident when I set the temp in that bathroom to 85 and it seems just enough to keep the room warm.

@Sal Santamaura - I don't get your point. Are you saying floor heating is a sales gimmick?

Good research on your part.

Yes you need to be aware of the individual room loads to see if radiant, alone, can heat the space. Kitchens can be another tough room to heat as the cabinets and appliances eat up a lot of the heat emitter, the floor square footage.

heat flux= the room dimension divided by the square footage of the cabinets and appliances.

Rooms a with a lot of glass can also be a tough go.

Generally about 24- 26 btu/sq ft is a comfortable number for residential radiant. Regardless of the type, electric cable, hydronic, forced air plenum floors.

As for your bathroom. set the stat for the temperature you want. Setting it to 85 will not allow the room to warm faster, or to that temperature if the floor doesn't have the square footage to cover the load.

What is the actual bath floor dimension, just the floor you can see. Not square footage under cabinets, tubs, toilets, etc.

Sal Santamaura

sniz said:

...@Sal Santamaura - I don't get your point. Are you saying floor heating is a sales gimmick?

No, not at all. Radiant heating, whether floor, wall or ceiling, is extremely comfortable and the best option if designed/installed properly and able to be afforded. I was commenting on the absurdity of calling vinyl flooring "luxury" just because it's now in strips rather than the sheet format that was common years ago. Flooring marketers denigrated it then, trying to upsell buyers to more profitable materials, but "elevate" it today. Proof that marketing can convince many people of anything.