The bathroom in my house doesn't get enough heat from the forced air primary heating system (it is too far from the furnace, and there is only a small duct going there due to the crawl space restrictions), so the temperature in this room is typically 3-4 degress F lower than the rest of the house (other rooms in the house are fine). I want the temperature in this room to be a few degrees above the rest, so I am thinking about installing a hydronic radiant floor heating underneath the subfloor from the crawl space.
3 out of 4 walls in this bathroom are the external walls, attic above the room and insulated crawl space below, tile floor, wooden subfloor. The heat loss for this room is likely around 5.500 BTU/h (calculated as a ratio to the entire house), but different calculators give different values in the range 3,200-9,700.
I want a closed loop for the radiant floor (not mixing the space heating water with the domestic water), so either a separate heater, or an external metal plate heat exchanger to the domestic water heater and an additional pump, or a new dual purpose heater (I need to replace the existing water heater tank anyway).
The amount of water in the space heating system is about 3.4 gal.
What heating source options would you recommend for this space and perhaps domestic water heating system, and what are their pros and cons?
3 out of 4 walls in this bathroom are the external walls, attic above the room and insulated crawl space below, tile floor, wooden subfloor. The heat loss for this room is likely around 5.500 BTU/h (calculated as a ratio to the entire house), but different calculators give different values in the range 3,200-9,700.
I want a closed loop for the radiant floor (not mixing the space heating water with the domestic water), so either a separate heater, or an external metal plate heat exchanger to the domestic water heater and an additional pump, or a new dual purpose heater (I need to replace the existing water heater tank anyway).
The amount of water in the space heating system is about 3.4 gal.
What heating source options would you recommend for this space and perhaps domestic water heating system, and what are their pros and cons?
- Completely separate small heater
- Is it allowed to use a small heater solely for space heating, if this is a secondary heating source for this room?
- Tankless or tank
- Gas or electric
- I hear that electric is much cheaper to install than gas, and maybe even not more expensive to operate for my scale (the gas is more expensive, but not too much for one room, and the heater doesn't require annual maintenance)
- However, people say that electric has low recovery rate, which is insufficient for floor heating purposes
- An external heat exchanger for the domestic heating tank
- It seems that the external metal plate heat exchanger (with the piping) is more expensive than another small heater
- Plus another pipe
- Plus heat loss in the exchanger
- Dual purpose water heater (maybe even with two internal heat exchanger)
- Brianwhite CombiCor is not available anymore, and I am not aware of any other
- Plus people say they were extremely unreliable
- Plus people say that it is impossible to balance the space and domestic heating power in them, so, in order to satisfy the domestic water heating needs, their space heating part will be grossly oversized for my scale, which means short cycling
- Combi boiler
- Expensive
- Space heating side will be grossly oversized for my needs