Not a gret idea.; `' Y9 Z) T% c$ s4 k8 N* k& c
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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.' T7 h2 j* g+ V
: P8 w6 b3 e& c- T# \2 j1 ?1 l; ]Beside,furnace hot water coil is made of metal. Some of it will come into the hot water.