We have a distinct dripping noise in our lower level family room. It seems to be coming from an inside wall near our cold and hot air returns. There doesn't appear to be any plumbing near by.

One thought was that the roof was leaking and water was getting between the walls. There is no sign of water anywhere. I'm ruling this theory out. Plus with -14 degree C temps I doubt that is possible.

The second theory is that perhaps a water pipe is expanding and contracting and causing noises in the wall. There doesn't appear to be any plumbing pipes in the area where the noise is the loudest although, we can hear the noise in the furnace room. Seems like an echo of the sound almost.

The third theory we had is that it isn't a plumbing problem but perhaps a hot cold problem with the furnace pipes. Perhaps condensation of some sort. I'm really not sure if that is possible. It is really cold hear right now and I'm guessing it has something to do with the house trying to stay warm. Does this sound possible?

We just moved hear last summer and our plumbing and furnace are all new, but the house is drywalled so we can't see behind anything.

Your thoughts and suggestions are appreciated.

Do you have a high efficiency furnace?

Is this a dripping or a ticking noise? Do you see any moisture? My bet's on expansion and contraction. Good luck, Tom