Not a gret idea.) J5 d# t4 P' x1 @& S9 I
& F2 U! J) B! f. C
Hot water has went through all your home's internal pipes whereas cold water comes "direct" from your local reservoir. Which should be pretty safe. + y* h( b: E7 | @' v/ s1 s* V9 U) z) f: q5 f, q$ w
Beside,furnace hot water coil is made of metal. Some of it will come into the hot water.