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Cold feet - Radiant subfloor heating question

Posted: Wed Oct 09, 2019 2:26 pm
by Domadosolo
My feet get cold in winter in my house in NC. I have an unfinished basement, with open fiberglass insulation in my basement ceiling. The main level floor is a bit cold in winter, and I want to install subfloor heating, just to take that edge off. This should supplement the natural gas forced air, that works fine, (new in 2015).
I hear that subfloor heat does wonders for comfort.
What is your experience with installation ?
How much should I budget?
Any DIY experiences?

Re: Cold feet - Radiant subfloor heating question

Posted: Wed Oct 09, 2019 2:28 pm
by oldfatguy
Not really your question, but why is your basement ceiling insulated?

Re: Cold feet - Radiant subfloor heating question

Posted: Wed Oct 09, 2019 2:56 pm
by deikel
I think it will be more cost effective to use socks and the infamous crocks (which provide their own insulation)

Secondary, I would think about either adding insulated flooring to your main level or use insulated tiles as a new flooring surface.

But based on your description that the basement has insulation in the ceiling and you still think the cold comes up the floor, I am wondering if you do not have air intrusion at doors or other draft points at the main level instead (the cold falling down and cooling at low level only suggesting it comes up from the basement)....just a guess

Re: Cold feet - Radiant subfloor heating question

Posted: Wed Oct 09, 2019 3:01 pm
by Domadosolo
oldfatguy wrote:
Wed Oct 09, 2019 2:28 pm
Not really your question, but why is your basement ceiling insulated?
It provides a layer of insulation between me and the unconditioned — cold (or hot in summer) basement temperature. The walkout basement has open ventilation vents and uninsulated walls at the back. 🙁. Its not used much

Re: Cold feet - Radiant subfloor heating question

Posted: Wed Oct 09, 2019 3:03 pm
by Domadosolo
deikel wrote:
Wed Oct 09, 2019 2:56 pm
I think it will be more cost effective to use socks and the infamous crocks (which provide their own insulation)

Secondary, I would think about either adding insulated flooring to your main level or use insulated tiles as a new flooring surface.

But based on your description that the basement has insulation in the ceiling and you still think the cold comes up the floor, I am wondering if you do not have air intrusion at doors or other draft points at the main level instead (the cold falling down and cooling at low level only suggesting it comes up from the basement)....just a guess
How’d I figure that out? It’s quite possible as the house/windows are 20yo

Re: Cold feet - Radiant subfloor heating question

Posted: Wed Oct 09, 2019 3:50 pm
by MarkerFM
Domadosolo wrote:
Wed Oct 09, 2019 3:03 pm
deikel wrote:
Wed Oct 09, 2019 2:56 pm
I think it will be more cost effective to use socks and the infamous crocks (which provide their own insulation)

Secondary, I would think about either adding insulated flooring to your main level or use insulated tiles as a new flooring surface.

But based on your description that the basement has insulation in the ceiling and you still think the cold comes up the floor, I am wondering if you do not have air intrusion at doors or other draft points at the main level instead (the cold falling down and cooling at low level only suggesting it comes up from the basement)....just a guess
How’d I figure that out? It’s quite possible as the house/windows are 20yo
Look at your electric company's website (Duke Energy?). Most provide a free home energy audit that will help you figure that out.

Re: Cold feet - Radiant subfloor heating question

Posted: Wed Oct 09, 2019 4:08 pm
by barnaclebob
The subfloor heat will cost a lot more to run and I'm not sure that your feet are cold because of your floors unless you are barefoot. I'm not sure that it works well to "supplement" a gas furnace with floor heat

Re: Cold feet - Radiant subfloor heating question

Posted: Wed Oct 09, 2019 4:16 pm
by LawEgr1
Hey There.

I understand you have cold feet? Well, I don't have much in the way of input aside from three tidbits:

1) We had a townhome we rented upon moving to Minnesota that had in-floor heating. It was awesome! I don't know what the cost to implement would be.

However...

2) May I kindly suggest a nice pair of nice wool socks instead. I'm sure you've tried something, but you didn't mention it. It's just that those of us in the great North generally don't have in floor heating due to this issue, and simply wear socks / slippers all the time. Probably a more cost effective option.

3) Check for leaks. Audit by the local energy company, you could probably get a tester at your local library (maybe? we have it...), or pay someone to do it, but be weary of that option. For us, it get's so cold (i.e. -15F) for so long that it's pretty easy to tell where the cold air is coming from :wink:

EDIT: three tidbits, not two

Re: Cold feet - Radiant subfloor heating question

Posted: Wed Oct 09, 2019 4:25 pm
by Domadosolo
LawEgr1 wrote:
Wed Oct 09, 2019 4:16 pm
Hey There.

I understand you have cold feet? Well, I don't have much in the way of input aside from three tidbits:

1) We had a townhome we rented upon moving to Minnesota that had in-floor heating. It was awesome! I don't know what the cost to implement would be.

However...

2) May I kindly suggest a nice pair of nice wool socks instead. I'm sure you've tried something, but you didn't mention it. It's just that those of us in the great North generally don't have in floor heating due to this issue, and simply wear socks / slippers all the time. Probably a more cost effective option.

3) Check for leaks. Audit by the local energy company, you could probably get a tester at your local library (maybe? we have it...), or pay someone to do it, but be weary of that option. For us, it get's so cold (i.e. -15F) for so long that it's pretty easy to tell where the cold air is coming from :wink:

EDIT: three tidbits, not two
Socks -arghhhh. Yeah those things... I’ve seen them before. Argyle maybe ?😀. Thanks for the tidbits

Re: Cold feet - Radiant subfloor heating question

Posted: Wed Oct 09, 2019 4:37 pm
by neilpilot
Agree with the sock suggestion, but if you decide to go forward with radiant heat consider limiting coverage to just the bathroom area. Only heat to open floor space; skip the area covered by the vanity, tub and/or shower.

When I completed a 2nd floor renovation, I decided to install radiant coils between the 2nd floor underlayment and the new tile floor in the bathroom. My wife, and our cat, both thought it was a great improvement.

It cost about $100 for materials. I halved the cost of the improvement by using a high quality dimmer switch in place of the temperature control box sold by the heat element manufacturer. I found that with minimal trial and error I could determine an appropriate setting for the dimmer, and simply left it set and on for the entire heating season. Since my heating element covered a small area the energy draw was insignificant, less than a high wattage incandescent lamp.

Re: Cold feet - Radiant subfloor heating question

Posted: Wed Oct 09, 2019 4:52 pm
by Domadosolo
neilpilot wrote:
Wed Oct 09, 2019 4:37 pm
Agree with the sock suggestion, but if you decide to go forward with radiant heat consider limiting coverage to just the bathroom area. Only heat to open floor space; skip the area covered by the vanity, tub and/or shower.

When I completed a 2nd floor renovation, I decided to install radiant coils between the 2nd floor underlayment and the new tile floor in the bathroom. My wife, and our cat, both thought it was a great improvement.

It cost about $100 for materials. I halved the cost of the improvement by using a high quality dimmer switch in place of the temperature control box sold by the heat element manufacturer. I found that with minimal trial and error I could determine an appropriate setting for the dimmer, and simply left it set and on for the entire heating season. Since my heating element covered a small area the energy draw was insignificant, less than a high wattage incandescent lamp.
Thanks. I have the possibility of adding the coils to the underside of the floor as I can access it behind the loose fiberglass from the basement. I’ll have to check if they can be installed against fiberglass.

Re: Cold feet - Radiant subfloor heating question

Posted: Wed Oct 09, 2019 4:53 pm
by Domadosolo
barnaclebob wrote:
Wed Oct 09, 2019 4:08 pm
The subfloor heat will cost a lot more to run and I'm not sure that your feet are cold because of your floors unless you are barefoot. I'm not sure that it works well to "supplement" a gas furnace with floor heat
I think you can call me barefootbob 😃

Re: Cold feet - Radiant subfloor heating question

Posted: Wed Oct 09, 2019 4:55 pm
by surfstar
Uggs are great. As a surfer, I was wearing them for a decade+ before Oprah put them on her wish list one year and then all the celebrities were wearing them to get coffee or walk their dogs in 65* CA "weather". They're great for cold feet after surfing and also for around the house in the winter.

Try some Uggs / warm socks + crocs / similar for this coming winter. If you still want to spend the $$ on subfloor heating or other costly ideas, do it in the spring-fall next year! i.e. - start small $ and work up

Re: Cold feet - Radiant subfloor heating question

Posted: Wed Oct 09, 2019 10:10 pm
by Tlmlb
Minnetonka slippers

Re: Cold feet - Radiant subfloor heating question

Posted: Wed Oct 09, 2019 10:20 pm
by NYCguy
Tlmlb wrote:
Wed Oct 09, 2019 10:10 pm
Minnetonka slippers
I have installed it in two houses as part of major renovations. I absolutely love it. It works wonders for cold feet. You shouldn’t need another heating source with radiant heat. Talk to a contractor. I expect it will be expensive.

Re: Cold feet - Radiant subfloor heating question

Posted: Thu Oct 10, 2019 3:26 pm
by deikel
Domadosolo wrote:
Wed Oct 09, 2019 3:03 pm
deikel wrote:
Wed Oct 09, 2019 2:56 pm
I think it will be more cost effective to use socks and the infamous crocks (which provide their own insulation)

Secondary, I would think about either adding insulated flooring to your main level or use insulated tiles as a new flooring surface.

But based on your description that the basement has insulation in the ceiling and you still think the cold comes up the floor, I am wondering if you do not have air intrusion at doors or other draft points at the main level instead (the cold falling down and cooling at low level only suggesting it comes up from the basement)....just a guess
How’d I figure that out? It’s quite possible as the house/windows are 20yo
As mentioned before - energy audits can be for free and are informative of general draft in the house, they should also bring an IR camera which may show insulation issues.

You can also run around and feel for yourself on a windy and cold day - skin works as a great tool

If you happen to be a smoker you can create smoke and see how it moves or get a professional smoke machine for little money in the Halloween shop (or beekeeper smoker could work too) - should also show you draft

Re: Cold feet - Radiant subfloor heating question

Posted: Thu Oct 10, 2019 4:32 pm
by onthecusp
Back when we lived in northern Ohio, we added subfloor heat to the kitchen area and loved it. Already had hot water circulating heat, so tapped into that with PEX pipe/tube which was clipped to the bottom of the floor on the basement side just like you are describing for your electric elements. Can't help much with electric advice, but it should work just as effectively.

I would not recommend it as "radiant heat" as in expecting it to warm up the room much. If the air temperature is otherwise comfortable it does not take much to take the edge off the cold floors. I like the idea of the high quality dimmer switch above (sized for the wattage), which would allow you to err on the side of more heating elements, spreading out the coverage, all driven at a lower temperature.

Re: Cold feet - Radiant subfloor heating question

Posted: Thu Oct 10, 2019 8:52 pm
by Domadosolo
onthecusp wrote:
Thu Oct 10, 2019 4:32 pm
Back when we lived in northern Ohio, we added subfloor heat to the kitchen area and loved it. Already had hot water circulating heat, so tapped into that with PEX pipe/tube which was clipped to the bottom of the floor on the basement side just like you are describing for your electric elements. Can't help much with electric advice, but it should work just as effectively.

I would not recommend it as "radiant heat" as in expecting it to warm up the room much. If the air temperature is otherwise comfortable it does not take much to take the edge off the cold floors. I like the idea of the high quality dimmer switch above (sized for the wattage), which would allow you to err on the side of more heating elements, spreading out the coverage, all driven at a lower temperature.
Thanks

Re: Cold feet - Radiant subfloor heating question

Posted: Thu Oct 10, 2019 11:59 pm
by Wannaretireearly
Installed in two bathrooms. Cost about 2k materials. Cant rem labor, not much in a new bathroom.
One of the best things we put in.
Now the heated tow rail. We never use!

Re: Cold feet - Radiant subfloor heating question

Posted: Fri Oct 11, 2019 12:26 am
by WaffleCone
I don't think radiant would be practical in your case. If you already had a boiler and were adding to an existing zone it might be worth talking about. With forced hot air you have all the hydronic boiler mechanicals that need to be installed-- mixing valves, zoning, pumps, etc. and that's before any tube is placed. The pex itself is cheap but better subfloor installations involve fastening long, heavy gauge aluminum channels to the bottom of the floor that the pex clips into. Then insulating underneath. The aluminum acts as large heatsinks and the insulation hopefully keeps the heat on the floor. Staple-up tube installations or those with thin aluminum track aren't very efficient from what I've read.

I never heard of electirc mats being installed under the subfloor but I suppose it's possible. They are cheaper to buy but expensive to run. Mainly used in bathrooms in the thinset under tile.

I just had radiant installed in a basement slab this summer and am anxious to fire it up for winter. But the best choice for you is to get some Darn Tough socks and seal up your basement so it's not so cold.

Re: Cold feet - Radiant subfloor heating question

Posted: Fri Oct 11, 2019 8:11 am
by lthenderson
When redoing our master bathroom, I installed some electrical radiant heat coils underneath the tile as sort of a test. We both absolutely love it. We often use this barefooted all year long and it makes us feel so much more comfortable when our feet our walking on a heated surface. The installation guide said it uses about the same about of electricity as an electric blanket. I cut that back considerably by hooking it up to a smart thermostat and setting it so it only runs in the early morning and late evening hours when we use that bathroom. It usually has enough latent heat that it still feels nice to bare feet for middle of the night bathroom forays.

I'm too cheap to put electrical coils elsewhere in the house and water heat isn't really feasible so we go with sheepskin lined slippers during the winter months.

Re: Cold feet - Radiant subfloor heating question

Posted: Fri Oct 11, 2019 9:40 am
by investingdad
We have a large master bathroom over the garage which is north facing. In the northeast, that means it gets COLD in there.

We decided to tile the floor last summer, maybe 100 to 150 ft2? Anyway, no way that floor wasn't going to be heated. We used a Schluter electric system with programmable thermostat.

Not only does it mean comfortable feet, it provides a thermal barrier to the source of the cold. So the room is more comfortable as well.

We love it.

Re: Cold feet - Radiant subfloor heating question

Posted: Sat Oct 12, 2019 10:23 am
by fogalog
If you are retro-fitting in-floor radiant then using a hydronic system will be fairly difficult and expensive to install. You need a decent depth of sub-floor or you need a new sub-floor over the top of the old one with grooves cut to hold the pex pipes. I have this system in my current house but I installed it as part of a major renovation. If you are prepared to replace the sub-floor then you can look at Warmboard for an idea of how the system is installed (NB: I didn't use Warmboard myself - it's expensive - we built up the sub-floor with grooves and installed heat transfer plates under the pex).

I know others have done it but I would not retro-fit a hydronic system underneath the existing floor from the basement side. You just lose too much heat and the sub-floor is not a great conductor. It will be warm but slow and expensive to run. If you're going to that much trouble & expense, might as well do it properly and replace the sub-floor.

To retro-fit in-floor heating to just one room I would use an electrical system. This involves laying a mesh with a conductor embedded in it underneath the (new) flooring. In your situation, I would lay this out on the existing sub-floor and then install something like a click-lock engineered wood floating floor on top. I have used a similar system in a house in Europe but I have not used this is the US, so I can't recommend a specific system, but Google tells me there are lots to choose from.

Personally I can't stand forced air systems - perhaps it's my European blood :D I love having radiant heat. I would definitely recommend it.

Good luck!

Re: Cold feet - Radiant subfloor heating question

Posted: Sat Oct 12, 2019 10:40 am
by OldBallCoach
My beach house is on a concrete slab and we have in floor radiant heat for the whole house and garages. We have a very efficent boiler and I have to say that this was a best call we ever made. The house has 10 zones and we can heat as much or as little as we wish and the whole deal is warm as toast and our energy bills are very reasonable. Our house is about 5400 square feet and our natrual gas bills run about 205 a month on budget plan. We also have gas water heaters, dryers and stove. I say DO IT! Warm feet rule, socks drool.

Re: Cold feet - Radiant subfloor heating question

Posted: Sat Oct 12, 2019 12:05 pm
by ScaledWheel
Agree with others that, if you don't already have hydronic heat it's probably too much trouble. Also, the heating is supposed to be installed in the subfloor, not under the floor. It'll be very inefficient to install it in the joist space under the floor. You also have to consider the flooring material, I feel you get the most bang for your buck with subfloor heating in tiled rooms. If you have hardwood floors there could be considerations about thermal expansion and contraction from the heat. In terms of cost, getting it done would probably be anywhere between $10-20/sq ft considering you don't have hydroponic heat already.

This all being said, subfloor heating in a bathroom coming out of the shower is amazing. Definitely something I want in my next bathroom.

Re: Cold feet - Radiant subfloor heating question

Posted: Sat Oct 12, 2019 12:57 pm
by fru-gal
Wannaretireearly wrote:
Thu Oct 10, 2019 11:59 pm
Installed in two bathrooms. Cost about 2k materials. Cant rem labor, not much in a new bathroom.
One of the best things we put in.
Now the heated tow rail. We never use!
Probably helps the towels dry faster, tho?

Re: Cold feet - Radiant subfloor heating question

Posted: Mon Oct 14, 2019 7:36 pm
by Domadosolo
OldBallCoach wrote:
Sat Oct 12, 2019 10:40 am
My beach house is on a concrete slab and we have in floor radiant heat for the whole house and garages. We have a very efficent boiler and I have to say that this was a best call we ever made. The house has 10 zones and we can heat as much or as little as we wish and the whole deal is warm as toast and our energy bills are very reasonable. Our house is about 5400 square feet and our natrual gas bills run about 205 a month on budget plan. We also have gas water heaters, dryers and stove. I say DO IT! Warm feet rule, socks drool.
Yes !