Solar Heating Payback

Our Most Popular Solar Space Heating system is to utilize the solar heating loop with a solar radiant floor heating loop, sometimes known as hydronic heating or in floor heating. The popularity of this type of system is because the investment in the solar heating loop equipment can also be used to power and control the radiant floor heating loop, eliminating this added cost.

The special solar storage tank has a 4.5 Kw heating element located in the middle of the tank. This means that the system is always capable of providing at least this amount of energy to the hydronic loop regardless of the amount of solar present including the evenings. The Resol BS plus controller is capable of handling two heating zones, this means it can control the pump on the solar heating loop as well as control the pump on the radiant floor heating loop without the need to invest in additional controllers.


A typical solar radiant floor heating loop will supply up to 50% of the heating energy via solar. It will also supply almost 80% of the domestic hot water supply. A typical 4 collector system averages 10,000 Kw (34,000,000 BTU) annually for solar contribution for both heating and domestic hot water savings. The average investment for this installation is about $12,000. A typical Hydronic heating system with controller cost is about $5000 with installation. At $.12 /KWhr the payback is as follows in the USA.

  •  Investment in solar heating system $12,000
  •  Less 30% tax credit $3600
  •  Less savings on Boiler installation $5000
  •  Total additional cost of Solar Investment $3,400
  •  Annual Solar Savings = 10,000KW x $.12
  •  Solar Savings = $1200

PayBack Period = $1,200/$3,400 = 2.8 Years

Sample PayBack Times

Energy Cost PayBack
$.08/ Kw 4.25 Years
$.12/ Kw 2.8 Yeaar
$.16/ Kw 2.1 Years
$.20/Kw 1.7 Years