Hot water heater for radiant floor heat
We are building a 360 sf kitchen/dining room addition to our home. We also dug out a 360 sf basement addition (and cut a hole in the existing basement). For various reasons we cannot use our current furnace to heat the addition (due to awkward duct-work and maxing out the furnace's capabilities).
Option 1 - We can install a Boiler (such as a Laars 84% JVH), with radiant floor heat in the main level and baseboard heat in the basement.
Option 2 - We've also been told that we can tie the radiant floor and baseboards into a water heater. Supposedly, the 350sf upstairs only requires 6,000-10,000 BTU's, and the basement won't require much heat because it's all below grade. Therefore the boiler in Option 1 is WAY more powerful than needed, and a water heater can easily handle this load. Does this sound reasonable? This option is obviously cheaper.
If a water heater is the way to go, I've got several questions:
A. What is the most energy efficient option?
B. Is there any possibility of using our current water heater? (A 50 Gallon Whirlpool Energy Smart Gas Water Heater, installed Jan. 2009)
C. If not, should we use 1 water heater or 2? ie, install a new water heater for the entire house, or just get a small one to fuel the addition? Or perhaps move the Whirlpool to the addition and get a tankless for the rest of the house?
At this point putting radiant heat in the entire house is not an option, only in the new square footage.
Either way, my husband will be doing the work himself (but don't let that scare you; he's very skilled, not your "average DIYer")
Thank you so very much!