There are few restrictions to the heat source you choose to use in conjunction with a radiant floor heating system. Some conditions, however, must be kept in mind for any heat source.
1) The heat source output must be sufficient to supply the heat required, including auxiliary requirements such as domestic hot water. Typical heat sources are low and high temperature boilers, designated hot water tanks, heat pumps, solar and, in certain regions, geothermal.
2) The maximum temperature of the water flowing in the PEX radiant tubing must be regulated to assure optimum comfort and to avoid damage to the PEX Pipe Tubing, or floor, and to prevent excessive floor temperatures.
3) The tubing must have a oxygen barrier if there is any ferrous metals used in the heat source or controls.
4) The heat load of the area being heated should be known. (BTU heat loss in square feet)
5) The maximum BTU output of the radiant floor should not be more than 25 BTU's per. foot. If the load is greater than the radiant floor can provide at 25 BTU's per foot then supplemental heat must be used. (Supplemental heat is used to match the heat load when the heat loss of the area is greater than 25 BTU's per. square foot.)
6) The maximum floor temperature for radiant floor heating should not reach above 85 Degree Fahrenheit.