In floor heat- Cold Climate

bizlady

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We have decided to sell our home next year, and downsize into a patio home. A patio home in our area is a one story house on a cement pad- no basement.

We live in MN, so the weather and the ground get quite cold in the winter months.

My question is directed to those with in floor (aka radiant) heat in cold weather states. Ideally with the same type of home. What is your experience with in floor heat? I can't understand how much of the heat does not just go to the ground, thus getting wasted. We will opt for the fluid filled tubes if we go this route.

We will be building a new home of about 1300-1400 sq feet. Is this an efficient and cost effective method to heat a home?
 
We had it in the finished basement of a prior home in the Twin Cities but not as our only heat source. Worked great there and it was definitely nice to have warm floors under foot. I believe it's just as efficient as forced air - the main drawback in the past has been the cost of installation but I believe that has been coming down.

There are plenty of resources out there - I found this one from Centerpoint which has a ton of customers here in Minnesota - http://www.centerpointenergy.com/staticfiles/CNP/Common/SiteAssets/doc/RadiantFloor_3574[1].pdf
 
My inlaws have in-floor heat in their ground-floor apartment in a part of China where it gets VERY cold (far north). It is very efficient and very nice -- warm feet all winter. Almost too hot sometimes. Heat rises, and in their case the floor is tile so it seems to suck up and radiate the heat pretty efficiently. I don't think much is lost below. The apartment is 10 years old and so far they've had no issues with it, and that is with generally low-quality Chinese construction.
 
We had in-floor heat in a previous house and currently have forced air. What we like the most about forced air is it heats the living space (not including the basement) more evenly. Our in floor did not, but it was an ancient system. OTOH, in-floor heat is much more humid, the forced air is painfully dry.

On a concrete slab using forced air in MN, it is hard to see how you would keep the floor warm during one of those freezing winters.

Great informative link by Fishingmn. From the pdf
• Heating can be directed to specific zones, even separate rooms, equipped with individual thermostat controls for added efficiency.
In floor, gas powered, with zone controls sounds reasonable.
 
Typically, you'll want several inches of insulation installed under the floor slab before it is poured. That insulates the floor slab from the earth. Prevents heat loss from the slab to the ground.

One reason you don't see infloor radiant heat as much, it has no ducts. You then have to pay extra to install all of the ducts if you want central air conditioning.
 
You will definitely want to get feedback from people using it in your area. As far as heat loss through the ground, two things: heat rises, and a good installation will have plenty of insulation underneath the coils.

The zoning with a thermostat in each room is a good thing for comfort and efficiency.

I have spent time at a relatives house with in-floor heat - for me, the floors got uncomfortably warm. Sitting in a chair and my feet would be hot.

This depends on your personal habits, but I like the way forced air heats a space quickly. I routinely lower the heat at night and when I leave. This saves energy, and the heat comes back very quickly when I turn it back up. I think in-floor heating is much slower, which has pros/cons. But if it took a long time to warm, I probably would not turn it down as often.

Oh, what about A/C? With in-floor heat, A/C will require ducts - the combo will be more expensive. (edit - like Masquernom said)

OTOH, in-floor heat is much more humid, the forced air is painfully dry.

I'm not sure there is any difference. Warm air holds more moisture than cold air. It makes no difference if it is heated by passing it over a hot air chamber, or heated by coils of hot water in tubes. But in a forced air furnace, it is very easy to add a humidifier on a humidistat. These work wonderfully, as they drain some of the water out, so there is no manual fill/drain and very little mineral build up as the draining does a constant flush of the system.

-ERD50
 
I am curious too, though I always assumed radiant floor heating was supplemental to a primary heating system (ie, forced air). An additional cost just to make bathrooms (where one is barefooted at times) and maybe kitchens more comfortable. I have seen the This Old House team put PEX water radiant heating systems in bathrooms and kitchens for years (so obviously not a primary heating system example, just for comfort), but they're target is leading edge luxury remodels.

If radiant floor heating was primary, I would think it would have to be slightly but uncomfortably warm to heat an entire house, especially in cold climates when the outside temp delta is high.

Also seems a little counterproductive unless maybe you have poured concrete floors, since whatever vinyl, linoleum, tile, carpet or wood (plus subflooring in all cases) you put over it would also insulate from the top. As noted, you'd want to insulate under the coils for sure.

Google didn't lead me to good answers, but I'm curious too since we may be building within a few years.

As always, you can find seemingly convincing articles online for and against radiant floor heating Focus On Energy: Shedding Light on Radiant Heat - Hvac, Radiant Heating, Slab, Solar Heating, Water Heaters, Flooring, Insulation, Heating, Forced-Air - JLC Online.

Here's an oldie using one house (meeting the OP "same type of home" criteria) to test both systems Radiant Floor Heating Systems Vs. Forced Air - Energy Efficiency, Hvac, Radiant Heating, Forced-Air, Heating - Remodeling Magazine that (controversially) says radiant heat was "22% less efficient."
 
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My in-laws have radiant heat. They live in Montana. It is VERY nice during those cold winters. Very efficient. The insulation below, and natural convection keep the heat from being wasted into the ground. The bricks above create a heat sink that radiates a nice even heat throughout the day.
 
I don't live in a cold climate and I have never had in-floor heating.

But, I just wanted to interject that in my opinion, any flooring option that makes one's feet feel good is worth it. Life is too short to have cold or otherwise uncomfortable feet!
 
I had infloor heating in my San Francisco condo (not exactly a cold weather climate!) Both under the tile in the bathroom and under the hardwood floors elsewhere.

It was heavenly, almost sensuous. :blush:
 
My parents live in a cold climate and use in-floor radiant heating as their primary source of heat during the winter (like many people there). I think it is very nice. I love to sit in the sun room with heated floors when there are several feet of snow on the ground outside!
 
From everything I've read (elsewhere), if I were building a house today I would have infloor heating without a doubt. Go for it!
 
My neighbor at my last house had in floor heating. A couple bad points were that it is very slow to heat up, so you can't just flip on the furnace and warm up the whole house in minutes like with forced air. Also, he had a few leaks and it was hard and expensive to find and fix them.

On the plus side it was very comfortable with the warm floors.
 
We have radiant heat in our walkout basement. IIRC we have (going upward) ~2' of 1.5" stone, 2" of foamboard, rebar, radiant tubing tied to the rebar and then ~5" of concrete. The 2" of foamboard prevents the heat from gong down.

Essentially, the tubing is roughly in the middle of the 5" of concrete and the hot water flowing through the tubing heats the concrete slab which in turn heats the floor.

We're very happy with it. Efficient, nice on the feet (cat loves it) and no floor space lost to baseboard radiators. Downsides are we have some spots that are warmer than others (probably more a function of the way I ran the tubing) and there are some limitations on the flooring that you can use if you want the radiant heat to be efficient. Our flooring is tile and vinyl but I understand that engineered hardwood can work well.
 
Hi,

I can't comment on cold climate (CA) but a word of warning. If you are going to have different zones: be very careful how you route the piping from the header. We made the big mistake of routing one key bedroom zone through a non-used part of the house (zone always off), resulting in total failure of heating for that bedroom.

Seems obvious now :-(
 
Our slab is all one zone (only ~1,000 sf) so we don't have that issue. I have a faint recollection that it is more challenging to zone radiant since you are heating the slab but i suppose if you planned the zones when you do the pour and have foamboard in the slab along the zone boundaries that it might make it more efficient to have zones since the foamboard would be creating separate slabs to be heated.
 
Hi,

I can't comment on cold climate (CA) but a word of warning. If you are going to have different zones: be very careful how you route the piping from the header. We made the big mistake of routing one key bedroom zone through a non-used part of the house (zone always off), resulting in total failure of heating for that bedroom.

Seems obvious now :-(

I'm trying to understand why total failure. I would think that instead the tubing that runs through the non-used portion of the house to the bedroom in question would just end up losing some heat and partially heat that non-used part of the house on its way to and from the bedroom in question.
 
Our cabin has a heated bathroom. It's on a slab with in-floor heat. As some have said it is not quick to respond to changes but it is great to walk on.
 
In floor radiant heat installed and designed properly is the primo method.


Advantages are:

Quietest
Most efficient ( all the heat source is located in the occupant zone down where you are and it heat whatever it radiates to, not leaking by convection to outside.
Does not stir up dust and aggravate allergies.
Most comfortable ( does not create drafts)
Can be easily zoned for excellent control if installed properly

Obviously when installed in floor or slab it must have several inches of high density insulation between the floor slab and the ground.
 
Thanks all for your comments and links. These have been very helpful and I think this is an alternative worth exploring for us.
 
Perhaps I missed it if this was mentioned, but you can't combine heating and air conditioning with floor heating like you can with forced air. Living in Michigan, I did without AC for years, but increasingly it is a necessity in these parts.
 
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Actually, I think you can to some degree by running cold water through the slab in the summer. I don't because ours is in a walkout basement which stays quite cool in the summer but I recall reading about it when I was looking into radiant.
 
Actually, I think you can to some degree by running cold water through the slab in the summer. I don't because ours is in a walkout basement which stays quite cool in the summer but I recall reading about it when I was looking into radiant.
The result would be a sopping wet floor, as the water vapor in the warm air condensed on the floor. In a forced air, air conditioning system there is a drain pipe that takes the condensation off the evaporator and sends it to a drain.
 
I have in floor heat in my basement and master bathroom. My first winter I kept it pretty toasty, until I got a $700 propane bill for 3 weeks. I thought it was going to be more efficient than that. I turned it way down in the basement just so it'd take the chill off the tile floor. My bathroom is kept a bit warmer. I put a cat bed in there and my cats love to nap there during the day. I like it but it's a luxury.
 
Our daughter had basement in-floor installed-her bills sky rocketed also. Turns out they had a bad install and replaced the type of boiler and are fine now.

If we proceed with this, our builder would install a backup gas forced air along with the central air conditioning. Seems silly in some respects to install two heat systems but at least we would have a backup if something happened to the in floor system.
 
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