Dear Patrick: There's no such animal as a 12,000btu gas water heater which uses power venting. I sincerely hope you aren't running your domestic water heater at 210degrees. Please e-mail me, or call with details on what you'd like to achieve and I'll try to be of some assistance to you. We have a 38,000 & 117,000btu tankless units which will do what you want, but they will both be oversized for a 14'x14' room. Brian at 800 851 9891.