Not sure if it's the supply or the return line but on of the air exchange lines if leaking water. The pipe is full and dripping through the duct and duct insulation. Just called builder and he's coming, but what would cause this? We are in Canada about an hour north of Toronto. We have a waterfurnace synergy 3d and an hrv venmer constroto 2.0. Our electricity usuage has decreased by 50 kwt a day while it is off.

Cold make-up air in ductwork within warm home likely has a temperature well below interior dewpoint, especially if home is artificially humidified. That could cause condensation on duct wall if insulation is poorly detailed.

That or snow has been blown into the intake air duct wherein it melts.

It's the cold air intake from outside that has the water in it. There is no snow near it, it has a cover on it with downward fin's so even if we did have snow I don't think snow could blow into it. It must be the dewpoint think. We don't have a humidifer. I thought the hvac was suppose to take care of all that. Basement is completly heated and that where the hvac pipes come through. We have radient infloor heat and find the house very dry. Its about 25% humidity.

I know they make insulated duct for bathroom exhaust fans that have this problem. Not sure if a similar insulated intake duct would help you.

Its already insulated with the proper duct work insulation stuff, so maybe it just needs more. The insulation is pink with a black cover and pulls right over the ductwork pipes, if I remember right they just pulled it over the duct work like a tube when they where installing it.

My guess the insulation on that duct is R4 or maybe R6 and that isn't enough when you’re pulling in really cold air. Basically the house air is condensing on the duct and then dripping off. The problem is now you have wet insulation which greatly reduces its R value and will cause even more condensation. Basically it needs to be dried out and more insulation added.

It's a venmer constructo. Our hydro usage has dropped 50kwt a day since Tuesday night when we turned it off. The builder is suppose to come to morrow to fix

Just curious, why do folks in Canada say 'hydro' for elect? Is it that most elec. is made from hydro?

Our electric company is called Hydro one.

Oh! So it's only in one part of Canada not the whole country? I first heard this watching Mike Holmes say this.....couldn't figure out WTH he was talking about at first! Why do they not refer to elect as elect??