Radiant floor heating anyone?

[jaywood]

Reason for my inquiry: My wife and I have our house on the market. We're hoping to sell our current house and build our "final" house. I'm interested in radiant floor heating, but haven't talked with anyone that actually has it installed in his/her house.

I'm hoping to get some feedback from those of you that have radiant floor heating. I've heard that it is a very comfortable heat. I'd like to know from those of you that have it if you:

1. Like it?
2. Are glad you got it?
3. Would get it again?
4. Have you noticed a difference in your heating bills since getting it (either higher OR lower)?
5. How much more expensive did it end up being (for purchase and installation) than traditional heating?
6. If you have a basement, how do you heat your basement?
7. What type of flooring do you have covering your radiant floor heating elements?

I'd also like to hear from anyone that was considering it and why you chose NOT to go with it.

Thanks in advance for the info!

John

[master53yoda]

Radiant heating is an excellent heat source. It is normally less expensive to operate then forced air for 3 reasons. 1 is that the house is normally zoned. and only delivers the heat needed instead of an average that is based on the location of the thermostat in a single zone forced air heating system. 2 is that most radiant heating is hydronic (water )based and the total operating efficiency is higher the it is on a forced air system due to the fact that the unneeded heat that is generated in the boilers remains in the water until it is needed. On a air system it is dissipated into the already overheated structure due to the thermostat location. the third reason is that it heats the objects in a room rather then the air. this raises the mean radiant temperature higher then a forced air system does and we are comfortable at a lower surrounding air temp then we are with a forced air system.

the basement floor can have radiant heat installed in it. the floor loss if insulation is placed under it is minimal. most radiant systems work best if they have hardwood or tile on top as the carpet does tend to insulate the system. but it still works as long as the insulation below the radiant system is greater then effect of the carpet above it, or you will heat the room below from the top.

They are far quieter then a forced air system, One thing to address whether the system is forced air or radiant, is if the structure is well built and very tight you will need to provide outside air through ventilation. The systems i have designed i normally use air to air heat exchangers for this pulling air from the laundry, bathrooms and run the exhaust system 10 min per hour or when ever the exhaust fans are turned on for 10 minutes. My design goal is 1/2 air change per hour of fresh air for the total structure.

the final drawback to radiant systems is if there is a need for central AC as at that point you end up putting in 2 complete systems.

When AC is required I try to design using hydronic air handlers with AC which allows zoning to a level required by the AC system which can be smaller if it is zoned correctly.

If the house is large enough I use boiler/Chiller systems with variable airflow on the air-handlers and individual zoning to each room. The structure needs to be larger then 6000 sq ft for that system to be cost effective

I hope this helps it is a bit long

[jackellis]

We just moved into our "final" house in the California mountains (elevation, 6200 feet). BTW there are six inches of new snow outside and it's 30 degrees at 10:30 AM.

To answer your questions:

1) Yes, we love it.
2) Yes, we are.
3) Absolutely.
4) Our heating, cooking and hot water bills will likely average $100/month. The typical annual heating load up here is around 7800 heating degree days compared with 4800 in Lexington. We use less natural gas up here than we did in the much milder climate of the SF Bay area and in a house that had 2/3rds or less conditioned space, but that may have more to do with good insulation and good sealing against air infiltration in the new house than with the efficiency of the heating plant.
5) Ours cost about twice as much. Typically it's even more expensive, but we built during a recession.
6) My shop and the ground floor also have radiant heat. You need to put insulation under and around the slab.
7) We used high quality engineered wood flooring in most rooms, carpets in some, and tile in a few places. All will work.

One question you did not ask is which method to use. We have a three story home. The slab is regular concrete (3 guest bedrooms and the shop sit on the slab). The top two floors use gypcrete for the subflooring with engineered wood, carpet or tile on top.

Radiant heating in the floor provides a very stable environment with no drafts. It takes time to heat up and it also takes time to cool down, so you have to be patient. You should separate rooms logically and install as many zones as you can so that you can keep unused rooms cooler.

If you PM me with a phone number, I would be delighted to talk your ear off about what we did and why.

[pelligrini]

I can't add anything to the radiant heating discussion, we worry much more about cooling days than heating days.

With mention of building your 'final house' be sure to give some consideration to accessibility. You don't need to make everything wheelchair accessible, but thought should be given to maneuvering spaces, reinforcement for possible future grab bars, control locations, level changes, etc. Giving it some consideration now will really pay off in the long run if you need it in the future.

*end of PSA, returning you to your regular HVAC talk*

[dbhost]

My brother has radiant floor heat in his home, so while my experience isn't direct, I do know a bit about his experience...

1. Like it?
2. Are glad you got it?

These two sort of go together in my view... Yes he is glad he got it...

3. Would get it again?

The reports are, yes he would do it again. (He lives in snow country. Radiant floor heat means no cold floors in the winter which is great when you go to the bathroom when you first get up...

4. Have you noticed a difference in your heating bills since getting it (either higher OR lower)?

Hard to say, his house was built with it, so no baseline to compare against...

5. How much more expensive did it end up being (for purchase and installation) than traditional heating?

Slightly more expensive than a traditional furnace. But not by much. I remember talking with him about it, and the difference in cost was very minor...

6. If you have a basement, how do you heat your basement?

His basement is unheated, and primarily a mechanical room and storage.

7. What type of flooring do you have covering your radiant floor heating elements?

Not sure I get the question. The flooring is poured concrete. The elements are in the concrete just above the rebar.

[phi1l]

+1 on everything yoda said. My parents put in all radiant heating in 1950. Floor Radiant in the basement & bathroom. Ceiling for the rest of the house.

after about 30 years the copper pipe in the basement floor started leaking & was replaced with baseboard heating. But I think using copper pipe in concrete is no longer done. That floor heat in the bathroom is really appreciated on cold winter morning ..the radiant ceiling heat works unbelievably well too. no drafts, no blower, just comfortable air temperature.

[herb fellows]

Second hand info, but a friend had it and loved it with one exception: he said when it was shut off for any reason, it took forever to get the heat back up. I don't know if this was specific to his situation or a general problem with the system though.

[master53yoda]

Second hand info, but a friend had it and loved it with one exception: he said when it was shut off for any reason, it took forever to get the heat back up. I don't know if this was specific to his situation or a general problem with the system though.

Low intensity radiant heat systems which are what is used in floors are slow to heat up because the floor temp very seldom is allowed to go over about 90 degrees, 80 is more normal max temp.

[capncarl]

I wanted radiant heat in my newly constructed house, but could not find a contractor that I was confident would install a leak free system. All the pros left aside, if the system is not installed properly it could ruin a lot of "stuff". Kinda like the new pex water systems being run in attics and walls. They are a disaster in the making.

Capncarl

[jackellis]

Kinda like the new pex water systems being run in attics and walls. They are a disaster in the making.

I'm not sure I agree. PEX has been used in Europe for a long time. A friend of ours who lives in Anchorage reports that it is used almost exclusively in new construction.

If couplings aren't installed correctly, the system can leak, but copper is equally susceptible to installation error. Based on the little I know about both systems, it seems like copper requires a higher skill level for installation and it appears to be a little more fragile. I like the fact that PEX is more forgiving if for some reason the heat goes off and the inside temperature drops below freezing.

With radiant floors, the trick is to use continuous lengths of tubing with no splices.

PEX is not the same as the PVC derivative that caused so many problems ten or 20 years ago.

[HarmsWay]

When we renoed our house last year we used electric radiant floor heating in the all the bathrooms. I had some experience with in-floor heating but was still surprised how much more comfortable it was. It's all under tile. I know of whole house systems that are done under hardwood as well but I'd still be leery of that. Having said that, my sisters home on the prairies is all in-floor heated (about 20 years old) and they love it and have had no problems under wood and tile.

[master53yoda]

I have worked around Pex for about 15 years, both in indoor piping and radiant systems.

In radiant floor applications i have seen no issues with PEX piping when installed properly with all connections accessible. and proper expansion provisions provided. Any installing company that is qualified should not have problems using PEX. The only problem that I have seen has come form nails being driven into the PEX and saw cuts into it. Both of these are eliminated if the piping is inbeded in some form of cement if that is a major worry. I have worked on many copper piping systems that have failed after 30 years, so we will need to see what happens with PEX over the long hall but with out exposure to UV light I don't think it will age and it isn't effected by abrasion or entrained oxygen as copper is.

[twistsol]

We installed a radiant floor retrofit in November / December of this year. So far we love it. I’ve attached a photo f the ceiling in my office where you can see it. I still haven’t gotten around to sheet rocking the ceiling in my office or the laundry room, the rest of the basement and garage are done.

1. So far we love it.

2. I’m glad it is done. We did it ourselves and it was more work than I ever anticipated. We installed 4200 feet of PEX with only two kinks. This was done by my wife and me, our three teenage daughters, and some help from friends and neighbors.

3. I think it is too early to tell if we’d get it again. The reason we did it is the south side of the house is about 60% glass. On sunny winter days, that side of the house is really warm, and consequently the heat never ran for the rest of the house. We would end up with 10-15 degree differences between the sunny rooms and the NW corner of the house. On cloudy days, the North wing was warmer since we’d tried to balance forced air heat. The radiant system has four zones so we can individually control the heat in the north wing, the master wing, the kitchen dining room area and southern exposure. Since we finished, we had a variance of no more than +- 3 degrees from 70 in any area of the house. I installed 18 min/max/average thermometers.

4. Since we’re on propane and we switched from electric water heat to propane water heat at the same time, I can’t really say. My electric bill dropped about $120 a month, 1/3. We did have the coldest winter we’ve had since we moved to this house and we used no more propane than we have in previous 5 years. We are also heating water with propane now.

5. Total cost for materials was about $11,000 and another $2000 for plumbing help. The plumbing related to the heating was about half of what they did. The rest was for other remodeling stuff that was going on at the same time and I figure while they’re here ….

6. We have a basement and it is 1100ft sq finished. We have everything in place for a fifth zone, but we didn’t put it in there yet. When we do, we’re going to run 1x4 sleepers on the concrete, run the PEX in between, fill the remaining cavity with sand, and then put ½ in sheathing over all of that. I’ll lose a little over an inch of headroom, but since the house was built with trusses and there are not bulkheads in the basement. I’m still contemplating adding a ½ inch rigid foam under the sleepers

7. Most of the house has either ceramic tile or hardwood. Eventually it will all be one or the other. We still have 80’s deep pile carpet in the master wing since we haven’t remodeled that area yet. It seems like the temps are more consistent where we don’t have carpeting, but the carpeted areas haven’t been remodeled and subsequently the insulation in that wing is not the same. Also, it’s above the garage which was un-insulated last year because we had to take down the ceiling to install the radiant. The ice storm over Christmas kept the insulation crew from getting up our driveway until late March.

The company we went with for the do it yourself installation is www.radiantec.com They were very helpful. I put three years of planning into this and probably spent ten hours or so on the phone and hundreds of emails over that time.

The pipe is held up by aluminum plates that help distribute the heat.


The manifolds came mostly assembled. I still ended up with nearly 500 joints I had to solder and only two leaks when pressure tested.