In floor Vrs Cast Iron Rads

salecker said:

Hi All
Looking for input on choosing between infloor and cast iron rads.
We have a second floor in our house that is a closed in loft,The floor will be insulated and the wall between the loft and vaulted ceiling will be insulated.The square footage of the bedroom is 440 and the bath is 120.
We will be installing hardwood flooring,home made from reclaimed fir beams.
We have enough cast iron rads already.And we will be using cast iron rads on the main floor.
Have some transfer plates,and a manifold for in floor loops.
So looking for the pros and cons of either system.
And does anyone have any btu ratings for cast iron rads?
Thanks Thomas

Click to expand...

I think hardwood flooring is not suitable for infloor heating . I think most use engineered hardwood flooring with infloor heat.
I have been using engineered hard wood over my infloor heating and it has worked well so far.
I think the problems with the hardwood is with expansion and contraction.

Cheers Huff

BTU ratings for cast iron radiators depends on the configuration of the radiator. There are several different sites that show what you are looking for.

http://www.colonialsupply.com/resources/radiator.htm

http://nepacrossroads.com/about3401.html

You have to run a pretty low temp (relatively) with hardwood based on what Huff said above. If you want to add the appropriate tempering you can use radiant, but if you dont mind lugging the radiators up the stairs, I would use those. They put out a nice heat, and can use a wide range of temperatures so you can run any storage you may have down low. For the bathroom you could consider one of the towel bar radiators if you want to save on some floor space.

If I was doing it new myself, I would go in-floor radiant, just because I like the radiant heat (very nice if you decide to tile the bathroom) and the fact that you can really squeeze heat out of a storage tank.

I'm putting rad panels in my house. They go in pretty easy for the most part. I have an old house with multiple floore layers and didn't think under floor radiant would penatrate threw it very well. I also didn't want to do that much work in a crawl space or insulate under the tubing. Only downfall I can see to the panels is the space they take up on the wall. The ones I'm using are about 3" thick double panel double convector, so a lot of btu for a small space taken up. On the plus side the rads are more responsive and with trv's you can keep each room at the desired temp.

Regarding wood floors over radiant, my experience is as follows:

a) Oak....horrible...separations and movement. Would NOT do it again
b)Jatoba(Brazilian Cherry) NOT ONE PROBLEM...no cracks, no separation no movement.(at time of install was cheaper than OAK) but much harder and kills your blades).

My infloor loops were actually running higher than needed temps...which exacerbated the problem, but the Jatoba held up great.

Good luck

Scott

radiant and hardwood can work well together. Keep the surface below 83F, underside bellow 115F. Humidity needs to be watched carefully. It is changes in moisture levels, humidity, that caused hardwood to move or panelize"

Check out www.launsteinhardwood.com They have done a lot of testing with wood floors over radiant.

I'd use an engineered wood product if possibe, they seem to be more stable with radiant.

hr

If you all ready have radiators I would suggest to go ahead and use them for that will get your system working in short order.3 years ago I went from a forced air system to installing cast iron radiators and have been well pleased with the results.

BTU rating are determined by how big your radiator is(EDR=equivalent direct radiation) and the temperature of water you circulate through it.The American Radiator Company put out a catalogue called the Ideal Fitter which list the EDR of the radiators they manufacturing,I'm sure other companies did the same but even if you have a different brand the Ideal fitter can help you size the radiator if you compare it to similar sizes in their catalogue.Copies of the Ideal fitter can often be obtained on EBay.This link may help as well http://www.heatinghelp.com/article-categories/158/Radiators.

If your radiators are over sized you can use much lower temps,I use outdoor reset with my rads and use temps between (105 -125 F).Using these lower temps helps me make better use of my storage.

For quick reference of BTU vs EDR

170 F =150 BTU per EDR
145 F =100 BTU per EDR
120 F = 50 BTU per EDR

In floor radiant is overrated IMO. The cost, labor and time spent playing around with temps is substantial. Over hardwood, one mistake and you have a mess. Rads on the other hand are easy to plumb, bleed and your done. And, of course they are radiant so you will get all the warmth of in-floor plus a place to warm pies, dry gloves, warm cold hands etc. The cast iron really holds the heat and will warm with 95º water. The draw back of rads is their placement takes up floor space (don't put one in front of a electric outlet) and they are hard to paint around when your wife changes her mind on room color. Place the rads 2 3/8 -2 1/2" from the wall for best performance.

The primary gain in effeciency from in floor radiant is due to the low temps, cast iron also will work well at lower temps if there is more of it.

Cast iron is luxury heat...if you have them use them. You will also save a ton of money, in floor radiant is expensive.

I clean and pressure test all at once. My household water is 55psi. I plumb hose fittings on the ends with a shutoff on the outlet, connect the rad to a hose from your tap water. Fill rad by removing the bleed valve at the top with the water on and the shutoff closed and putting it back in when water flows out clear then flow water in both directions at full force (much more pressure and flow than my heat system). Once the water runs clear for 10 minutes you should be in good shape. Turn off the shutoff valve with the rad full to pressure test. This has worked for me on some really messed up, stored outside for years rads. I suppose you could run some acid cleaner though it during the process but I never have. My system has treated water to help keep them clean. Just a warning; once you get these fired up, you will want to change over your entire heat system to rads. They're that good. As far as painting, get off all the old paint, keep the coats light and don't use high temp paint because of it's insulating properties.
Pat