We have been remodeling our home for several years. Last year we installed new Jeld-Wen replacement windows. The exterior siding (cedar board and batten) was replaced with hardiplank shake siding. The lower half of our home is rough hewn logs with mortar chinking. The windows downstairs have not been replaced. They are 6 over 6 single pane with exterior storm windows.

This is my problem. This winter the downstairs windows have condensation on the upper half only of the interior side of the storm windows. The upstairs replacement windows have condensation on the interior of the windows. It is a LOT of condensation.

Do you think this is from interior moisture trapped inside the house? We have made the home much tighter with the new siding and windows. We did have a drainage problem before which we resolved by installing drain lines around the perimeter of the house. We have not installed gutters around the house as of yet. That is a project for next year.

We do use gas (propane) logs for heat on occasion. I know that propane will dump moisture into the interior. But, we seem to have the problem everyday that the exterior temperature is below 40 degrees whether we use the gas logs or not. Did not have a problem in the summer.

Any ideas? It is very annoying and obviously not a good thing.

Thank you for any assistance.

A couple of questions:

What type of heating system do you have?

What are the locations of the heat outlets, whether they be radiators, baseboard or air, relative to the window locations?

Have the windows insulating glass, or removable double glazing?

In modern houses, heating is located so as to cause an updraft at the windows, to counter the natural downdraft that is generated by the cold glass, and this tends to mitigate or prevent condensation, at least in all but extreme temperatures.

It could well be that the original house was drafty enough that moistutre could escape, and that the renovations have tightened the house to the point that moisture accumulates.

Another question: do you have good exhaust fans in all bathrooms and the kitchen, and do you faithfully use them whenever moisture-producing activities are taking place, such as cooking, showering, and bathing?

The condensation is caused by a combination of cold glass and high interior moisture, and it can be mitigated by either raising the temperature of the glass, or by decreasing the amount of moisture in the air, or both. It's that simple.

Thank you for your posting. We have two heat pumps. One for upstairs and one for downstairs. The vents for the upstairs system is opposite the window wall. And the new windows are double paned insulated glass. (That does make sense to me that there is no heat on that window wall to warm the windows and the old exterior siding probably did allow the moisture to migrate out and since we have tightened up the siding it has no where to go.) I do not use the heat pump unit upstairs much as we prefer to sleep in a chilled room.

I have a downdraft vent system on my stove and I do try to use it. The downstairs bathroom is vented as well, but seldom used. The upstairs bathroom is not vented. We are in the process of a remodel there and it will have a high efficiency vent fan when completed.

I will be unable to move the heat vents to under the windows. I suppose my only hope is that when the master bath remodel is completed the new exhaust fan in there will take care of my moisture problem. I will start by using my downdraft vent in the kitchen faithfully!

Thank you for your assistance.

We built a new home and had the option of installing an air-to-air exchanger. The total cost for the unit and installation was $1500.00. It runs off of a humidistat, which you set yourself, and controlls the amount of moisture in your home. We have never had moisture on our windows and yet the house is not too dry. Just another option for you and it is well worth the cost! Thanks, Minnesotacool