We're noticing a lot of condensation on our windows. Where's it all coming from? We're in a small house in San Diego. It has a single wall-furnace. It's typically about 70F inside the house, and the outside has been between 35-60F (it's been relatively cold here), and we've had rain on/off for the last couple of weeks, so the ground is wet/moist. I think/hope the condensation is normal but I'm worried this could be a sign of a problem that could grow into something serious. What amount of condensation should we be worried about? We have not noticed any mold yet, except a little bit on the bathroom tiles. Our windows are old, single-paned windows, so I think the house isn't all that air-tight. Should I be worried?

Thanks.

 

Are you using a humidifier? If you take showers, is the bathroom vented to the exterior of the house? Do you have a crawl space? If so, have you looked down there lately?

 

We're not using a humidifier.
The bathroom is vented to the outside.
There is no crawlspace (the house is on a slab).

 

The single pane windows will invite condensation due to being colder. Drapes or curtains will make the glass surface even colder.

Make sure your furnace is venting properly, assuming it is gas, one of the byproducts of burning gas is water.

They make switches for bathroom fans that will keep the fan running for an adjustable period of time after they are turned off. This gets rid of much of the excess moisture from showers.

Pick up a humidistat to know where your humidity is.

Other sources of moisture are drying cloths inside, non-vented dryers, excessive cooking, a lot of people, firewood stored inside, or hidden water leaks.

HH
Bud

 

Condensation on windows in the winter is caused by not enough ventilation. Increase ventilation and you should be fine.