Radiant Heat & hardwood floors? carpteted floors?


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Old 08-26-04, 01:19 PM
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Radiant Heat & hardwood floors? carpteted floors?

I live in an old house with pretty small rooms. the wall radiators do a great job but installing radiant heat for the first floor would help a lot with laying out the rooms. Especially in the Kitchen/dining room area. The kitchen is linoleum and the dining room is carpeted. The rest of the first floor is hardwood floors with some area rugs. I've been consistantly told that I will have to go with a high density pattern to get the btus without damaging anything but I've botten very conflicting opinions on wether it would even work, wether it would screw up the hard woods and wether my oil bill would go up-stay the same- or go down. I'm OK with staying the same but not up. I could easily do the layout and install myself. I'd just need a little help tying it into the system as a separte zone. Opinions please.

P.S. I tried to do some searching but the search button option seems to have dissappeared from my screen. Odd to say the least.
 
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Old 08-26-04, 07:21 PM
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There is no reason to think that radiant heat would not work in your house. Your fuel bills should be less than your current bills due to the temperatures at the difefrent levels in the room. I wouldn't spend the savings yet because they may be small, but typically radiant heat costs less to run. Make sure that you don't run the 180-200 degree water through the radiant tube. You will need a mixing valve and some other controls. It should no cause any harm to your hardwood and although you may need to add insulation under the tube, your carpets do not pose a problem either.

Ken
 
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Old 08-28-04, 12:52 PM
Homer Simpson
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Radiant floor or radiant underfloor

Speedy,

Your last name isn't Gonzales, is it?

Radiant floor design isn't easy, it is more than running a lot of pex tubing.
Are you doing this or are you having it done by a professional installer?

If you have hardwood floors, the Pex( crosslinked Polyethelene plastic tube),
is installed under the floor in the joist cavities.

The floor temperature on hardwood and vinyl floors should not exceed 80 degs. All kinds of shrinkage and cupping on hard wood floors with higher
temps ocurr. Vinyl floors are uncomfortable to walk on in bare feet, too.

This is the way it works. You have to know how many BTU/H per sq. ft you are going to need the radiant floor to emit on the top of the hardwood floors
to overcome the BTU/H loss thru the wall, floor, ceiling,windows and doors on
the the coldest days of winter with an indoor temp of 65 degs for the kitchen and living room, etc..

When I say 80 degs., I don't mean that the water going thru the tubing is
80 degs.. The water in the tubing can be 140 degs.. It depends on the
thermal resistance between the tube and the top of the floor. This is calculated manually with the Ashrae tables or with a computer program.

Therefore, you can have less tubing at a higher temp or more tubing at a lower temp to to achieve the btu/h per square foot requirements, but remember the top of the floor is only 80 degs. In all likelyhood, the water temp in the tube is low so you are going to have much more tubing. (density?)

You will need mixing valves, manifold with flow controls, pump or pumps, tools
to connect the pex, thermometers, heat transfer plates, bushings, and the
pex and the connectors. Sound easy?

There is no point in continuing if you are going to have a professional do it.

Radiant flooring isn't cheap, but, it is the most satisfying heating there is.
Savings are really in the boiler. Old boilers are inefficient, the new modular
condensing boiler are money savers, big time.

Your oil bills will not increase, most likely go down because the heating is even
across the floor and the hot air rises, heating the area where you live (six feet
from the floor up). You're more comfortable at a lower set point on the thermostat.

Go to the Wirsbo or Zurn websites and call their headquarters and try and
con a radiant heating design book out of them and read it. Or buy them they are about $25 each.

Say goodbye, Homer. Goodbye
 
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Old 08-28-04, 02:30 PM
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My initial post was a little misleading. I am under no illusion about the difficulty in designing a radiant floor system. I believe I could handle the install without too much grief. There is a company that had an ad in a magazine last year for self installed radiant heating. You give them all the data and they design the system and sell you all the required equipment. That's what got me thinking about it. Profesional install would likely put it out of reach. As it is we are likely going to put more $$ into the house than we will get out. Hopefully we stay long enough to enjoy our labors. Yes by density I meant a lot of pex & transfer plates to make sure that I would have enough BTU without temperatures going to high. Like everything else there is probably a balance point where too much tubing is as bad as too little. I just don't know yet. There are four reasons I'd like to do this.

1. Open up floor space in a small old home with small rooms (500 Sq.\floor)
2. Comfort
3. Fuel savings (as if this will ever be offset by the cost of doing it)
4. Switching to a direct vent gas system to solve problems with ancient chimney & oil tank. I could also put the new boiler in a MUCH more convienent location. Gas is being run into the house regardless.

I'm considering trying this in the kitchen/dining area before winter so I can monitor temps over the winter to see how it's all working out. That's a lot $$ for a trial though but that's also the one place where I really do need the wall space back. right now the kitchen rad is stuffed up under the counter and the dining room rad has soft copper tubing bent to the point that it is kinked to get it up through foundation. I'm trying to think of all of this stuff now in the hopes that we can spend a couple of years working on it and then sit down and enjoy it for years to come. THANK you for the info.
 
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Old 08-29-04, 09:45 AM
Homer Simpson
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Okie Dokie

Speedy,

I see that you are serious about this.

What is the name of the pex system that they are using? I use Rehau products, myself. But, there are many manufacturers of PEX products.

Since you have a professional design, what you need to do, unless they come
to your home and do it, is to make sure that you provide them with accurate
HEAT LOSS CALCULATION. Without knowing how much heat you are losing
thru the exterior of the house in winter, it is imposible to design a system with
any degree of accuracy.

As far as boilers go, my favorite boiler is the MUNCHKIN. It is a condensing
boiler, which means that it produces liquid condensate from the flue that has
to be drained away. How your house is presently plumbed determines choice
too. The Munchkin is quiet, small, and very efficient.

There are tricks and tip in installing PEX underfloor. But that can come later.

Best thing is to familiarize yourself with the pex products and product applications. The more knowlege you gain the easier and better the job.

Most of the companies will gladly send you information on their products and
installations. Until later. Say goodbye, Homer. Goodbye
 
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Old 08-30-04, 07:28 AM
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Wink

Out of the box here, but think about it. Had a job" cold room" after they put a pad and carpet down on the floor. had to add hot air baseboard to the room to get it warm.

ED
 
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Old 08-30-04, 11:03 AM
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heat loss calcs and garage options

The biggest problem right now is timing. The heat loss calculation is going to change significantly as I replace windows, blow insulation into the walls, address the crawl space and insulate the attic. I'm in that big catch 22 position of which to do first.
Well the FIRST thing that has to happen is to finish the garage as that's the place that's going to make the money to pay for all of this stuff. The garage is a more modern structure that I'll be able to better predict heat loss.
This is a two story with my office/showroom going upstairs and a small shop going downstairs. I also need the HVAC in the office to be quiet. Radiant heat would be excellent for that but I don't think it will be practical for these reasons;
1. the floor joists for the second floor are undersized so it will be difficult to provide the required amount of insulation to direct the heat up and it could be difficult routing the pex without further reducing the structural integrity of the building.
2. It doesn't do me any good for the downstairs as I have no intention of busting up the slab to put it in the floor. I'd love to do it so I could work on my antique car more comfortably but the costs of breaking up the slab just don't make sense and a plywood sub floor to hold a car just doesn't seem practical.

My least favorite form of heat by far is hot air but that seems to be the most practical option. The smallest HVAC system I can get, feed to both floors with a few precautions taken for noise. I'll just have to have a way to balance the air flow between the two floors. There's no reason to keep the downstairs as warm as the upstairs except for the days I'm working in the shop.

The only practical way that I've come up with to do this is to use a HVAC system for AC on both floors and hot air downstairs with a different unit to run the radiant floor heat for the office and the domestic hot water for the sink and shower stall. Any ideas?
 
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Old 08-30-04, 11:14 AM
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Wink

Have put in hvac set up with duct for down and one for up with a balance damper in it that worked manual by hand. They work just fine. I think you said noise ,make the first part of the duct out of the fiberglass ductboard it will kill the noise for you.

Ed
 
 

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