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Transitioning oil fired baseboard heat to in floor radiant

Hopefully this will work.
Current system is 25 year old oil fired boiler 2 zone (first floor and second floor) and hot water off of the boiler.
I am completely renovation first floor and want to use in floor radiant instead of baseboard.
My idea is to use the boiler itself just for the second floor and to run the first floor radiant through the hot water unit.
My understanding was that the radiant water is at a significantly lower temp which may harm the boiler (both in heat temp and return temp).
Please correct if I am wrong, but if I run the first floor radiant through the current hot water heater and just return it to the the water heater and recycle I can use the lower water temp and not harm the boiler? Can I set this up to also get some cooling effect in the warmer weather?
Any input on this will be helpful. I am just a homeowner trying to work this idea through.


  • Snowmelt
    Snowmelt Member Posts: 1,295
    heat lost calc- I think your over thinking but trying hard to be cost effective , do you have gas in the home. your base board would be over sized just for one floor.
    why not do radiant on both and use a water heater with higher btu and a 2nds water heater for domestic water.
  • Jamie Hall
    Jamie Hall Member Posts: 17,125
    If it were me, I would not use a water heater. Water heaters are built for heating domestic hot water. Boilers are built very differently, for heating water for heating systems. What I would do is run the thing primary/secondary, possibly with a buffer tank with the radiant running off the buffer tank and the boiler running from time to time to keep the buffer tank up to temperature.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • Paul S_3
    Paul S_3 Member Posts: 1,257
    Do all radiant....use a tekmar 356 for injection mixing....this will provide boiler protection and full outdoor reset for the system ..... and its not expensive...i do this all the time....when its time to replace the boiler it can be reused
    ASM Mechanical Company
    Located in Staten Island NY
    Servicing all 5 boroughs of NYC.
    [email protected]