I am very new to radiant floor heating, and I am trying to figure out what heating source options may work for me. I've contacted different contractors, and they give very different recommendations on the heater. I realize there is no perfect solution, and trying to understand pros and cons of various options.
I need to heat 2 rooms in my house. The rest of the house is heated fine by a gas furnace, but these 2 rooms are the farthest from the furnace, and their temperature is typically 3-4 degrees Fahrenheit below the temperature in all other rooms. These 2 rooms are bathroom and a walk-in closet, so I want their temperature to be a few degrees above the temperature in the rest of the house, which likely means that I need to install a separate heat source for them.
The 2 rooms are next to each other (share one wall), both have an attic above and an insulated crawl space below, high ceiling. The bathroom has 3 external walls and 2 large windows, the walk-in closet has 1 external wall and no windows. The bathroom floor space is 200 sq ft, and the walk-in closet floor space is additional 110 sq ft. Depending on the calculator I use, the heat loss from the bathroom is 9-12k BTU/h, and the heat loss from the walk-in closet is 3-6k BTU/h.
The crawl space underneath both rooms is accessible. The bathroom has a tile floor, and the walk-in closet has a carpet. I am not ready to replace the tile in the bathroom (so heater installation between the floor and the subfloor is not an option at this stage), but can replace the carpet in the walk-in closet.
I can heat the walk-in closet with a small portable heater, and the carpet there may limit the efficiency of a floor heating. Would be nice to heat both with the same system, but if I need to chose, the bathroom is a much higher priority.
I have a 40 gal water heater tank for the domestic hot water now, but I am going to replace it.
- Is installing a floor heating underneath the wooden subfloor between the joists is an option? I hear different opinions on it
- If it is between the joists, does it have to be hydronic, or can electric heating system be used there as well?
- If the carpet is a challenge for a floor heating system, would water heated baseboards be a good option to consider for the walk-in closet?
- I hear that a boiler is great, but even the smallest boiler would be too big to heat these 2 rooms (I don't have a boiler now)
- I hear that something called combi-core may be a solution, but some people say that it is very unreliable, and some say that it is very reliable. What is your experience?
- Is there an option to use a single on-demand tankless water heater for both the floor heating and the domestic hot water supply? What are its pros and cons?
- What other types of gas/electric heaters and mixers should I consider for this system? What are their pros and cons?