Not a gret idea. # W- ]9 h+ u9 ?: r) d4 R5 O- w# I- t/ R) z
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.6 u. J( n% d: L4 |; K
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Beside,furnace hot water coil is made of metal. Some of it will come into the hot water.