Condensation on New Windows
Condensation on New Windows
I had new windows installed this summer and as it's becoming colder, we are seeing small amounts of condensation on the interior side of several windows towards the edges. Primarily the only windows we see this on are those facing due East. We live outside of Washington DC and have a whole house humidifier which is set at about 50%. Is this to be expected or should I contact the installer? What's causing this?
Hey Dex, Your in the ballpark for humidity. I usuall tell customers to try 40 percent. Usually the windows that will get any moisture on them would be the Kitchen or Bathroom windows. I know Oberon will be more logical and detailed in his answer when he see's this. So I will stay clear of that detail. What I can offer are some quick inspection suggestions. First and most important is making sure all the sashes are closed and locked down. Many customers who call me back with this issue have not locked their windows down. Either the cam locks or the sash locks are not secured. So make sure they are locked down. Next thing is during a cold night or morning run your hand around the edge of your new windows. Do this when your furnace is running as this will be drawing a vacuum that can help find any leakage. You will feel the cold coming in when you hit the spot where it's leaking. If the unit has a leak coming around the frame. It's usually near the area where any moisture is forming. Another thing I've seen is your humidity gauge is not reporting the correct rating. This does not happen often but does occasionally catch us off guard. Check these items out. Hope they work.
Guy
Guy
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Dex
Condensation on the inside of your windows is a result of too much moisture in the air of your home. This condition is common in winter as many tend to over-humidify. Humidity levels in winter months should not exceed 40% (30-35% is recommended and 50% can cause many problems).
The heating system doesn't remove water vapor from the air, but by heating the air, it makes it possible for the air to hold more. Since the air has the same amount of water vapor that it had when it was cold, the relative humidity falls. This happens because relative humidity measures how much water vapor is in the air compared with how much can be in the air.
In the case of windows, condensation will often occur at the edge of the glazing because of conduction through metal spacers and air convection within the glazing cavity or an improperly sealed unit. The warm, moist air your system is pushing through your house is hitting the colder edge of glass and reaching it’s dew point (condensation).
You have two options to reduce or eliminate the condensation. You either need to raise the inside temperature of the edge of glass or lower the relative humidity of the indoor air. As an “rough†example, if you have 70 degrees inside and a relative humidity (RH) of 50%, that edge of glass will reach it’s dew point (DP) at about 50 degrees surface temp. If you keep the same 70 degrees but lower the RH to 35%… it will lower the (DP) to about 40 degrees.
Hope this helps a little.
FenEx
Condensation on the inside of your windows is a result of too much moisture in the air of your home. This condition is common in winter as many tend to over-humidify. Humidity levels in winter months should not exceed 40% (30-35% is recommended and 50% can cause many problems).
The heating system doesn't remove water vapor from the air, but by heating the air, it makes it possible for the air to hold more. Since the air has the same amount of water vapor that it had when it was cold, the relative humidity falls. This happens because relative humidity measures how much water vapor is in the air compared with how much can be in the air.
In the case of windows, condensation will often occur at the edge of the glazing because of conduction through metal spacers and air convection within the glazing cavity or an improperly sealed unit. The warm, moist air your system is pushing through your house is hitting the colder edge of glass and reaching it’s dew point (condensation).
You have two options to reduce or eliminate the condensation. You either need to raise the inside temperature of the edge of glass or lower the relative humidity of the indoor air. As an “rough†example, if you have 70 degrees inside and a relative humidity (RH) of 50%, that edge of glass will reach it’s dew point (DP) at about 50 degrees surface temp. If you keep the same 70 degrees but lower the RH to 35%… it will lower the (DP) to about 40 degrees.
Hope this helps a little.
FenEx