Not a gret idea.# e# o3 U* M% v6 X6 ]
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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. " ~% b3 V* n( x& S- }" e" a9 O# v$ ?7 ^7 R9 u
Beside,furnace hot water coil is made of metal. Some of it will come into the hot water.