Not a gret idea. 5 n* d8 M- C. S2 c E8 x+ k+ M2 `) a2 ]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. / q; n: o* O; Q9 M8 W) k( x9 s0 ~- U& }) L2 g. a2 ~ e
Beside,furnace hot water coil is made of metal. Some of it will come into the hot water.