Thoughts on radiant heating a concrete slab floor of a sunroom. (fireplace, furnace)

[toot68]

The house we bought in Chapel Hill, nc has a 15'x15' sunroom built on a concrete slab (rest of house on crawlspace), that the previous owner had converted from a screened porch. No heating was installed, we are considering putting in an electric radiant heat source on top of the slab and laying tile over it. The plan is to remove the doors that separate the sunroom from the rest of the house, and will just want something to efficiently heat the slab so it isn't too much of a drain on the furnace heating the rest of the house on cold days (maybe 20-30 days/year).

My online research has led me to Warmly Yours floors, I'll be interested in hearing if anyone has any opinions on their product or similar radiant heating systems, and whether this is a reasonable plan for heating this space.

Thanks

Jim

[Cornerguy1]

I've only had experience with hot water radiant floor systems, but a couple of thoughts occur to me.

The object here is to heat the floor above the slab and then the air space of the sun room. If you lay a radiant element directly on the concrete, that element is going to sink a lot of its heating effort into heating the mass of the concrete. While it's true the heated mass of concrete will put some heat back into the room, a fair bit of that heat will also be absorbed by the soil underneath.

If you're determined to go with radiant, it might be wise to put down a layer of good quality reflective insulation on the slab before installing the radiant element.

If the space only has to heated for 20-30 days a year, perhaps some type of radiant wall heater(s) and a reflective insulator under the new tiles might be more effecient.

Removing the sunporch doors will certainly open the space up to the adjoining room, but it will also remove the option of being able to close off the sunporch on days you don't wish to heat it. It also removes the "close it off" option if the space gets too hot in warmer weather and you don't wish to air condition it. Maybe a nice set of French doors?

[Davart]

Originally Posted by toot68

The house we bought in Chapel Hill, nc has a 15'x15' sunroom built on a concrete slab (rest of house on crawlspace), that the previous owner had converted from a screened porch. No heating was installed, we are considering putting in an electric radiant heat source on top of the slab and laying tile over it. The plan is to remove the doors that separate the sunroom from the rest of the house, and will just want something to efficiently heat the slab so it isn't too much of a drain on the furnace heating the rest of the house on cold days (maybe 20-30 days/year).

My online research has led me to Warmly Yours floors, I'll be interested in hearing if anyone has any opinions on their product or similar radiant heating systems, and whether this is a reasonable plan for heating this space.

Thanks

Jim

Hey Jim I use it in bathrooms under tile, don't remember the brand but it works well, it does suck some juice and 15X15 is a good space to heat and you're heating the slab too.

In my sunroom I use a ceramic radiant gas heater (Glo-warm), about 35K BTU's and I'm heating a sunroom of that is 25X22 a wall mount gas heater heats it well and if it breaks it's easy to get to to replace not to mention cheaper like $200 ... try a easy fix on floor heat if it breaks!! I ripped up a floor a few years back for someone who's floor heat broke.

However if you do not have gas or propane this is not the best option.

[toot68]

Originally Posted by Cornerguy1

The object here is to heat the floor above the slab and then the air space of the sun room. If you lay a radiant element directly on the concrete, that element is going to sink a lot of its heating effort into heating the mass of the concrete. While it's true the heated mass of concrete will put some heat back into the room, a fair bit of that heat will also be absorbed by the soil underneath.

If you're determined to go with radiant, it might be wise to put down a layer of good quality reflective insulation on the slab before installing the radiant element.

If the space only has to heated for 20-30 days a year, perhaps some type of radiant wall heater(s) and a reflective insulator under the new tiles might be more effecient.

Removing the sunporch doors will certainly open the space up to the adjoining room, but it will also remove the option of being able to close off the sunporch on days you don't wish to heat it. It also removes the "close it off" option if the space gets too hot in warmer weather and you don't wish to air condition it. Maybe a nice set of French doors?

The manufacturer recommends laying down a cork mat between the slab and the element. We're open to other suggestions, main concerns are doing something that will give us credit for the extra 225 sqft heated living space and also not creating a huge energy sink.

Our contractor had the same comment about wanting to close off the space. We priced out folding doors, and were getting quotes around 15K. We wound up getting a 14' double sliding glass door, that yields a nearly 6' gap, but just aren't happy with it. It was wonderful when there was a 15'+7' hole in the wall. We'd really like to move the glass doors to the back of the sun room and open the place up.

[Cornerguy1]

I'm not sure what kind of bucks you're talking for the radiant, but have you considered something like a direct vent gas or propane fireplace?

Depending on your decor, it might be just the ticket on a cool winter's night.

If you really like the entire SR being open to the adjoining room, then go with it and hang the disadvantages. You can always add a partial wall and doors in the future if necessary.