Here's how to calculate your electric load, so you'll know if it's feasible to add a heat ... Include 1,500 volt-amperes for each 120-volt 20-amp kitchen circuit, and likewise for a 20-amp laundry ...

Feeder and service load calculation requirements can be found in Part III of Art. 220 in the 2014 NEC. As noted in Sec. 220.52(B), "A load of not less than 1,500VA ...