Condensate Water Drains

Most Air conditioning units and some high efficiency Furnaces produce water through condensation as the  system operates.  In cooling mode, A/C unit indoor sections cool the air below its dewpoint causing water vapor in the air to condense.  Furnaces with an AFUE rating of 90-97% cool the exhaust gases  from the burners to the point the water vapor in the exhaust condenses as the heat is transferred to the indoor air.