Not a gret idea. . y* H% j2 r+ @* A6 `; t: L 7 f H# L+ a" B3 m1 @; uHot water has went through all your home's internal pipes whereas cold water comes "direct" from your local reservoir. Which should be pretty safe. & f8 g& U. a) A8 S* w1 a3 k' D+ L5 z! h' E5 ~/ ]4 @
Beside,furnace hot water coil is made of metal. Some of it will come into the hot water.