Old House Hydronic Retrofit

Steve Carlson_2

correct. Since the under floor tubing would be required to supplemnt the CI. I was hoping it could do the ENTIRE job without having to restore the CI radiators to a workable state. This was a boiler system that has not been used in MN for 30+ years. Who knows what condition the CI radiators are in. I just found the archived thread on transfer plates vs no transfer plates. Transfer plates would probably help me bridge the design gap. I'm still reasearching.... -=Steve=-

Steve Carlson_2

Old House Hydronic Retrofit

I just returned from a spring home and builders show here in southern MN. I had stopped off at a HVAC contractor booth and was discussing my upcoming home renovation project. Part of the renovation was to convert an old fuel-oil fired boiler and cast iron radiator system to a ground sourced heat pump and hydronic under floor heating. (dry install with Wirsbo extruded aluminum joist traks) The gentleman at the booth told me that I'd end up with warm floors, but this setup would not be the primary heat system for the entire home. He said there would be too much resistance for the heat to go through both wood flooring and sub floor. This is a two story brick structure and each level has 3/4" wood subloor with 3/4" maple hardwood. I had planned on under floor install for both levels (incuding fiberglass insulation to push the heat up) . He said the only way to heat a home soley with hydronic heat is to lay the pex on top of the subfloor and enclose in a thinset and cover with a thin finish flooring (tile/thin harwood, thin carpet). Is this true? I want to have hydronic floor heat, but did not want to tear up all the existing hardwood flooring. Thanks for your input. -=Steve=-

kevin coppinger_4

He is probably...

right. W/o running the numbers it would be a long heat up time...Why destroy your classic CI system? given the right set up your comfort level can be much increased....kpc

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Steve Carlson_2

Doesn't concrete ...

Doesn't concrete have long heat up times too? Is that really the issue, or is the problem that not enough BTUs of energy will radiate through the floor to heat properly? I was told earlier that my geo exchange system would not work with the CI radiators since the geo water temp is lower than the traditional boiler temp. Not enough BTU output from the CI for max load requirements of the home. I really was hoping to install a ground sourced heat pump. It would be a big energy saver in the long run for this home. So are people installing under floor dry mounted hydronic systems and still heating with forced air or other heating systems? Seems like a big expense for just warm toes. -=Steve=-

Mike E_2

While a ground source heat pump may not put out a high enough temperature to heat the house using just the cast iron radiation, or just the under floor heat, possibly running them both together would put out enough heat.

To find out for sure, you need to the run the load calculations and get the performance data on the heat pump/CI/underfloor system. Then you can see how they will all work together.

Michael

Wayco Wayne_2

Do the math!!!

It could work, depending on the heat loss and the water temp. If the water temp isnt high enough you can boost it with a mod con boiler. Although ground source hp's should be able to reach 120 degrees, which is usually enough for joist trak plates to shine, depending on the heat loss. WW

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Constantin

Depends on the house...

... and your budget.

The water temperature range of a GSHP usually limits you to temperatures no higher than 120°F. Putting the pipes on top of the floor will may be able to cover most houses, but it all depends on local conditions. Some places in MN are colder than others...

Then there is thr insulation schedule on your home, whether you're going fix up the windows, etc. Only a heat loss program is going to give you all the answers you need, so that is where I would start. Make some "what if" scenarios to see whether you can heat the place with your planned system.

I too would not go away from the radiators you have, but it is your home. I have a RFH system in our home, but the renovation was a gut job. Thus, we were able to replace floors, walls, etc. after fixing everything. Consider the magnitude of such an undertaking...

lee_7

We just finished a staple up radiant system with 3/4 plywood subfloor and 3/4 hardwood on top. System works off on oil boiler on a p/s loop. The homeowners love the warmth of the floors and house.

Steamhead (in transit)

Is the radiator system

steam or hot-water?

To Learn More About This Professional, Click Here to Visit Their Ad in "Find A Professional"

Steve Carlson_2

System was Hot Water

All the radiators will need to be pressure checked with new valves etc... Any tips where I can get new CI radiator parts? -=Steve=-

Ed Lentz_2

My brother in law installed an under floor radiant system in a 100 yr old farm house. Most of his floors are 2" thick or more. He used rigid foam instead of fiberglass in the floor joists. It takes him a long time to get those floors warm but it does work. He is using a wall mount water heater to do it. It is a rube goldberg installation, but it has worked for two years here in Michigan. His water temp is around 130 I think. Not suggesting anything, just saying.