We are finishing our basement (house is 5 years old). We had an hvac contractor put in ducts and returns in the new space…these vents are all closed and the return is sealed (we are still wiring and plumbing). Also, he repaired our humidifier which was not working. Now I see that we have had condesation running down the wall from the air return in our living room (main floor). I assuming that something we have changed is causing this. Any ideas? Thanks so much.
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The return carries air that is at room temperature. Assuming the living room and basement are at roughly the same temperature, condensation is unlikely. If the basement is 20 degrees colder than the living room, then condensation is to be expected, especially with the humidifier working at full blast.
Make sure it is really condensation, i.e. the duct in question is sweating all around. If it's just water in a spot, it could be from an unrelated leak somewhere nearby. And condensation "running down the wall" could be simply that wall itself condensing. Is it an outside (foundation) cold wall in a warm basement? What is the ambient temperature and wall temperature? What is the ambient relative humidity?
Need more investigation and information for an educated guess.
DG/Builder
We have insulated the basement and even with the vents closed it is roughly the same temperature as the upstairs. I should have said in my previous post that I can see where water ran down my wall below the return. However, it is not wet right now.
My humidifier has setting for different outside temps. We have it set for 20 degrees (35% humidity). Is it possible that a few very cold days we had last month (6 degrees daytime and 11 below at night) would have caused this to happen because I did not adjust the humidifier to a lower setting?
Last winter was the first for us in this house and I now think the humidfier never worked (despite home inspector saying that it did....).
thanks!
Laura, it is very unlikely to have condensation under those circumstances. If the temperatures are roughly the same throughout the house, there is no reason for condensation to occur in only one spot. Suggestions:
1. Blow some powdered chalk (colored chalk if wall is white) onto the affected area of the wall. You can buy powdered chalk in red or blue at the hardware store for use in chalk lines. Just put the powder in your palm and blow onto the wall. When the water happens again, you will see tracks in the chalk leading to the source.
2. If the location is close to an outside wall, make sure there is no air leak to the outside that makes the spot much colder than the rest of the house.
Without actually seeing it, it's hard to diagnose any further. Next time it happens, take pictures and post them here.
DG/Builder
Try turning the water to the humidifier off.Wait acouple days and see if it helps.If it does your humidifier maybe running all the time instead of just when your furnace fan [blower] is on . Hope This Helps Red
Big Red, the furnace-mounted humidifier cannot be "running all the time". Even if it is mis-connected, it does not have a fan of its own (at least the vast majority don't). It needs airflow from the furnace to evaporate water and to carry the water vapor into the house. Without airflow it will evaporate exactly the same amount whether it is on or off, i.e. a negligible amount.
DG/Builder