moisture on sills

The moisture from the window is from your humidistat being set to high. When the Temp drops the differance in temperature will cause moisture to collect on the windows.

If she has a new furnice and humidifier there is usually a temperature probe that is placed in the attic or outside the will adjust the amount of moisture. Temp increases automaticly decreases humidity in house.

If it is old like the one i have, i just turn it down when it gets cold. It has been 5 degrees in chicago and i had to almost turn it off so my windows would not ice.

 

Maybe , maybe not

 

Got a very similar issue. My house is older, but was completely redone in 2006 (down to the studs) with all new spray foam insulation (making the house super tight). Last winter I noticed a pretty substantial build up of condensation along the bottom edges of the windows. After lots of research and speaking to people at my office I had some go-do's to check the window seals (came out OK by doing a temperature check by laser gun of the inside and outside panes, shouldn't be more then a 10-15 degree difference), ran my bathroom vent to the outside last winter (originally vented to the attic), and even played with the thermostat. I know that for me, keeping the heat 5-8 degrees warmer (live in Maine usually have it set to around 60-62) dramatically reduces the moisture from the windows by slightly increasing the surface temp of the inside pane (only works with good window seals).

Condenstation still occurs for me so my next step is an air-to-air exchanger or heat exchanger, still doing research to figure out which one is better for my application. Also not sure if I can install that properly, don't really want to pay someone to do it...but if I have to I will.

Or installing a pellet stove wtihin the house. I'm thinking installing a pellet stove will act like a woodstove and suck the humidity out of the house when in use which should really help with the condensation issues i've been having.

That's what I've found, hopefully this helps your situation OP!!

 

I came up with 3 possibilities
First, 'upgraded' doesn't always mean they're good windows. I hate to say it, but there are a lot of builders these days that sell useless upgrades to people who don't know better. Someone mentioned she is in a quickly developing area, that means lots of housing built in a short amount of time, corners cut, costs cut to maximize profit, etc. I don't know the builder, and I hope it's not the case because they give good builders a bad name but poor quality windows could be the cuprit.
Second, even if they are good windows, if they weren't installed correctly, that could lead to condensation issues. Cold air gets around the frame and makes a cold spot on the inside, causing condensation. Ask her if she can feel a draft on her hand at the perimeter of the windows on a cold, windy day. On a calm day, she may not notice, when it's windy, you'll notice if they weren't installed correctly.
Lastly, since you said she did upgrade pretty much everything, the comment about the heating system having a humidifier that's set too high is definitely a possibility. In that case, you'd either need to turn the humidification system down or turn the heat up to help support the extra humidity.

Either way, the windows are a potential issue. They aren't thermally broken well enough to stop condensation. You can't have condensation if there isn't a localized temperature drop to cause it. That doesn't necessarily mean they're 'bad' windows, but they're certainly not top of the line.

 

Even the best windows can condensate with the right conditions , thermally breaking the windows only keeps the frame from transfering the cold from outside to inside. , in a typical double thermopane window you are still only looking at an R value of the glass at R3-R4 even in the most expensive windows

The point made about voids around the frame is a good one

 

This seems to be a problem with newer homes because they are built so tight. Warm, humid air is trapped inside and when the temperature drops it takes longer for the humidity to escape. We've had the same problem with our one year old home this year when we had a 40 degree drop due to a cold front. I opened the fresh air intake to help the humidity drop faster, but the bottom line is the humidity inside is too high and it condenses on the coldest area (the windows). It will eventually even out. Others have good recommendations such as use exhaust fans to help control humidity, use a dehumidifier, etc. You could even suggest opening some windows for air transfer to speed things up.

 

I guess I should have been more clear, your clarification about the R value is what I was getting at. Even a good quality window usually won't have an R value as high as the adjacent walls. There are windows available that could do it but they come at a cost most home owners wouldn't (or couldn't) swallow.

 

No problem , I'm not disputing what you said , just adding to the discussion

 

She is not in a rapidly developing area north east ohio and out in the country with not much but cows around her.

 

Another possibility:

Does she use propane for cooking? By product of propane is moisture. I remodeled our kitchen and wifey wanted one of those fancy professional gas ranges in gas. But we didn't get a hood with enough CFM to match. The result was lots of moisture that collects on the windows as that's the coldest surface. Replaced the fan with a bigger one and the moisture level dropped over 20% from 75% to low 50s%.

 

O think it is gas... don't know if propane or not