I recently had High Efficiency furnace installed (Carrier Infinity) and there were 2 PVC pipes put outside my house - one is for taking air into furnace and another one for air out of furnace. When furnace is working, my second pipe is spraying water out of it - not a lot, but still hand feels wet if you hold up to it. It seems kind of strange. Is that a good furnace installation? Should it be like that? If yes, then would it not freeze in the winter?