We own a 2 1/2 year old bungalow in Cambridge, Ontario, Canada. In cold weather (i.e. below 40 deg F.) we experience extremely heavy condensation on the inside of our double-glazed windows. This occurs even though we have a ventialtion fans and 2 dehumidfiers going almost constantly. However, these units use a LOT of electricity. In really cold weather the condensation turns to ice. The Builder has told us, "Just crack open a couple of windows"........not exacrlt an energy-efficient thing to do in the dead of winter. Would some having some kind of HRV system installed on our central heating system (curently a high-efficiency natural gas furnace) solve the problem? If not, any other suggestions would be helpful and appreciated.