Electric Radiant Heat

Status
Not open for further replies.

mtn_elec

Senior Member
Home owners asked me yesterday about putting radiant heater on floor so they wouldn't use BB heaters (hot water) HAve any of you guys have install this before to replace regular hot water heating systems? In other words is this floor heating enough to warm up a large room?Thanks for your replys
 

jeff43222

Senior Member
Re: Electric Radiant Heat

I've installed them in bathrooms and kitchens. My impression is that they are a nice supplemental system, but I wouldn't want to use them to replace a boiler system. They also take a while to heat up.

Living in the frozen north, we pay a lot of attention to heat, and I've never seen anyone heat their whole place with radiant floor heat.
 

charlie b

Moderator
Staff member
Location
Lockport, IL
Occupation
Retired Electrical Engineer
Re: Electric Radiant Heat

I have an older home that only has baseboard electric heat. I don't like its inability to make the room feel warm. If this system the homeowner is talking about is radiant only (i.e., no fans to push air past the heating elements), then they are not going to like it either. If they are talking about a system that heats the entire floor, I have never seen such a system in use, so I can't offer an opinion.

I prefer gas forced air, but there is no gas service on my block yet. :(
 

jeff43222

Senior Member
Re: Electric Radiant Heat

I have natural-gas forced-air heat in my own house, and this is generally what is installed in my area these days. There are still plenty of houses where I live that have old boilers, gravity systems, octopus systems, etc.

Earlier this year I met a pipefitter on a job, and he told me the ideal way to heat a house was with a hot-water forced-air system. I thought he was pulling my leg, but it seems that such a system does indeed exist. They do cost a lot more than a natural-gas forced-air system, which would probably explain why they aren't all that common. The pipefitter put one in his own house, but it was obviously a lot cheaper for him than it would be for the rest of us.
 

al hildenbrand

Senior Member
Location
Minnesota
Occupation
Electrical Contractor, Electrical Consultant, Electrical Engineer
Re: Electric Radiant Heat

Nieto,

I've installed several flavors of in-floor electric heat systems. Here in MN, we have a design temperature of -20?F. The systems I have personal experience with are supplemental. These are around 3 Watts per Ft?.

But, I have to say, setting foot, bare or in socks, to a warmed floor is the bee's knees!! :)

The best answer to your question is to do a heat loss calculation for the room, to determine the KW of heat required for the design temp there in NJ. If the KW required by the heat loss, spread out over the Ft? of the space equals or is less than the output of a system that will install in the material the floor is constructed out of, then go for it.

Keep in mind, this in-floor system will be on a separate thermostat, most likely, so open passages to other heat zones will have an effect. Also, insulating the floor below the heat source to a high R is beneficial, if not required.
 

tshea

Senior Member
Location
Wisconsin
Re: Electric Radiant Heat

If the HO already has hot water heat, they would be better off by upgrading the radiators. The electric radiant heat is only supplemental. It is really designed to warm the floor for socks and barefeet, not whole house heating. There just isn't enough watts/ft2 to do the job. Our design temp is also around -20F.
You could suggest radiant heat in the bathroom(s) and suggest HO contact a erputable HVAC contractor--maybe friend of yours!

edited to add:
Just read an article this morning that suggests 12 W/ft2 to obtain a comfortable level of heat in a room. Keep in mind you don't need an overkill because the heat is at a lower level (height-wise).

If you used electric radiant heat for a 1600 ft2 house x 12w/ft2= 19,200 watts @ 240v = 80Amps
Do the rest of the math to calculate operating cost.

[ December 30, 2005, 12:10 PM: Message edited by: tshea ]
 

e57

Senior Member
Re: Electric Radiant Heat

You and the HO may be talking apples and oranges... Many higher end home have it here, and it does really do the trick. As said before, most of the electric stuff like Nu Heat and such is only enough to reduce the chill for the bare foot experiance. They are floor warmers only... There are some manufafurers who do make some that could be used as real heat, but the wattage per ft is out of control. Talked to a guy who does both REAL electric HEAT and hydronic, something like ~15W sq/ft? (Says he uses it only in special circumstances.) If you had you're own generation, like solar, geothermal, wind all at the same time it might be cost effective? The hydronic PEX plumbing in the floor via solinoids controlled by thermosat to a boiler are enough to crack the floorboards. They are really effective, and from what I understand pretty efficiant. It is what most people install here...

Many homeonwners who read too many magazines will get the idea, hear that you can do it with water, or electric. Then often confuse the floor warmer stuff for the stuff that could actually heat the place. The one thing they have in common aside from being to different animals, is they both cost a fortune to install. And both have to really be designed for the floor covering type, and thickness.

And personaly, as an electrician, I would not want that much wattage under the floor boards. Imagine a lost neutral with that stuff...

edit: The guy i was talking about was installing somthing simular to this stuff: T-2 (apparently the company TYCO doesn't sell it in the US...)

[ December 31, 2005, 05:01 AM: Message edited by: e57 ]
 
Re: Electric Radiant Heat

As an HVAC contractor in Illinois I've worked on and installed both hydronic and electric in floor radiant heat. Electric is extremely expensive to operate so until the price of gas triples I would never recommend it for whole house except in Florida and even then the install cost is extremly high. Hydronic on the other hand works great for stone or tile floors, but I've seen less than optimum results with wood or composite floors... and whatever you do don't add carpeting or large area rugs especially with padding. They'll pretty much insulte you from heat. With pex tubing and the new reflective foam backing kits installtion isn't bad either... of course it'll still cost more than baseboards.
 
Status
Not open for further replies.
Top