My house was built in 1999 and I have all Anderson windows. I have no condensation. So one wonders if the problem isn't house related instead of JUST window related. Condensation comes from so many places and causes that it's hard to define where yours comes from.

Activities like cooking, showering, even BREATHING contributes to water vapor in the house. If the house is wrapped in visquine, which WAS a building practice years ago,this will also trap moisture in the house. It's a complex question to answer.

60% humidity sounds pretty high to me. Thermopane glass still has SOME coolness to it, and if the humidity is real high that cooling of the high humidity air MIGHT cause condensation. Why don't you try dropping the humidity and see if the problem goes away?

There's nothing wrong with your windows. Your house is simply way too humid!

The usual recommendation from building scientists is a max of 50-55% in the summer (lower in the basement) and 25%-45% in the winter. Above that level, you're creating an environment enouraging mould growth, dust mites and mildew.

Here is a link that might be useful: Building America Performance Criteria

I agree with GreenZeus and Worthy -- that humidity is way, way too high. I'm surprised you don't have mildew problems in the bathrooms, closets and under the sinks.

But you are still stuck with rotten, black (possibly mildewed or moldy) window sills now. Check with the Home Repairs forum, but I expect the sills should be replaced, with possible replacement required of water-damaged support beams. Not something to delay doing!

I put PeachTree wood framed windows in a house that I built in 1990. The wood is still perfect. The new owner finally repainted the house last year...it hadn't needed it since my original paint/stain.

We have Hurd wood framed now (2.5 years) and there is no condensation problem.

I love the depth and definition of wood framed windows, so that's what I always use (built 3 houses here in NC).

Cameron

60% hunmidity? Yikes. You really need to get that down. Does the range hood vent to the outside? Do you have vents in/near the showers, and are they used?

An air exchanger in the house won't help if you are deliberately keeping the house humid. I have Andersons and we sometimes have a little bit of condensation on the bottoms, but it goes away when the heat clicks on in the morning (we keep at around 55 at night). The Andersons are not the issue. In the new house you could get all vinyl windows (inside as well), but the high humidity will cause other issues. It's really, really bad for people with allergies, especially a dust allergy.

There are lots of windows out there. We are happy with our Andersons. The Marvins were too expensive (like 3x as expensive because I didn't like the Integrity line) and we didn't like the Pellas. If money was no object I would do Marvin.

During the first winter in our new home, I noticed slight condensation at the bottom of our Eagle windows. Considering the price we paid for them, I called our builder out to investigate. The first place he looked was our humidifier on the furnace. He said it was up way too high and lowered it. The condensation went away immediately and we haven't had a problem since.

With Duette shades in our previous house we had a huge condensation problem in the winter; in the mornings we had ice sheets all over the windows on the inside. We replaced the sills with marble, and all was fine after that.

You have condensation on your windows, and as you identify that is a problem. The obvious answer is to remove the moisture and you remove the source of condensation. However every action has unintended consequences. You sufficiently dry that interior air, you will remove the source of condensation. However you may make the house unlivable for you or your partner, and that is an unintended consequence. So exactly what problem got solved? Well at least you dont have condensation ;-).

Now lets see if we can understand your situation, and only through understanding can we come up with a workable solution. You like 60% relative humidity in your house, and I would identify that this is plenty high. For reference, I run my dehumidifier to 40% R.H. in summer, and 45% R.H. in winter  I have a very tight house and run supplemental dehumidification year round. Like you, if it gets too dry I tend to have problems, and as I get older I actually prefer more humidity. Now my questions for you are what is the surface temperature of your windows, what window treatments are you using, and what is your target indoor air temperature?

Let me illustrate why this information is needed. Assuming you keep your IAT at 70F, and at this temperature the saturation vapor pressure is somewhere around 25mb, so 60% R.H. would have a vapor pressure of around 15mb. At this vapor pressure, if the surface temperature of your windows is cooler than 55F and you donÂt have air moving across those windows, the air next to the windows will cool below the dew point and you get condensation. Now then, drop that R.H. to 45%, and you will get condensation on your windows at 45-50F. Drop it to 25%, get nosebleeds daily, use 3x more skin moisturizer, and be generally miserable, and you can get the surface temperature of that window all the way down to 30-35F before you get condensation. This is only one part of the equation - temperature.

Your windows are 11 years old, so I think it is a fair assumption to say that the seals are probably broken so your argon fill is gone (assuming you had it int he first place, and if a spec house probably not). I woke up this morning, it was -5F outside. The place I am has thermally broken aluminum frame high performance gas-filled windows. Now I donÂt care what relative humidity you have inside in this environment you will see condensation if the air is not moving.

As Susanka point out, when you put shades or curtains up, you restrict movement of air on the surface of that window, allowing that air to cool to the surface temperature of the glass (and if that surface temperature is below the dew point you get condensation). The easy answer is to remove humidity, but this may not actually buy you much if your glass temperatures are too low. However the less obvious answer is to increase airflow across surface of the window to prevent the air from cooling to the surface temperature of the window, thus eliminating condensation.

I think the best answer is a combination. I would reduce the R.H., make sure your window treatments are not restricting airflow across the surface of your windows, and increase air circulation in your house (ceiling fans). And in a new house, I would recommend fiberglass windows  far superior to anything else currently available in the residential market.

60%RH is excessively high and there is probably plenty of condensation you cannot see (like inside walls) doing damage.

brickeye - that depends if mommyof5 is running positive or negative pressure (and to a lesser extent the quality and location of the vapor barrier). While I am an advocate of positive pressure, in certain conditions negative pressure is net beneficial. This is one limited case where it is. However I doubt that most people actually know whether the house is operating under positive or negative pressure.

It is still very difficult to ensure that no interior air is getting into any space at a lower temp, no matter what the overall pressure is.
Sealed spaces of any significant size still have convection flows inside.

I have found that the cost of double-hung windows varies considerably from region to region and from whom you buy them.

In the northeast, the cost of the Andersen 400 TiltWash (PVC clad frame, coated sash) and the Marvin Integrity (all fiberglass) are about the same (withing 2%).

Using the Andersen 400 TW as a base, there should be about an 18% premium for the Andersen Woodwright (PVC clad frame, composite clad sash).

There should be about a 23% premium for an Eagle Talon (aluminum clad)

There should be about a 30% premium for a Marvin Ultimate Double hung (aluminum clad).

It is my belief that each of these premiums represents an excellent value and that it is well worth considering spending the additional money. I would recommend the Andersen Woodright as a base model in terms of quality, durability and archtectural features although none of them can match the Marvin Ultimate DH for architectural detailing options.

The cheapest window is the one that lasts the longest with the least maintenance cost.

Our estimate for a mix of Anderson 200 and 400 was about $17k. The exact same list using Marvins was over $50k.
Of course, this was 4 years ago, so I don't know what it is like now. We've been happy with the Andersons.

Thank you all for the responses. To answer some of your questions...kast year we installed a humidifier on our furnace because of the dry skin and throat issues. We had condensation on the windows before that was installed. The temp. in the house is 66 degrees and we do have bathoom vents that do get used. The stove vent doesn't vent to the outside (builder error) and I know that isn't helping. About half of the windows are not blocked by window coverings. They have just as much condensation as the ones that have blinds on them. Today I turned down the humidifier from 40 to 25. I'll wait to see any improvement.

Our window sills are not damaged at all, it's where the latch is that had to be restained and varnished. I don't understand why KCMO-Ken thinks the seals are broken?? Is that something we can see or does a rep need to come out? I'm very happy w/ the Andersen windows and I'm pretty sure we'll put them in the new house.

kcmo_ken said:Your windows are 11 years old, so I think it is a fair assumption to say that the seals are probably broken so your argon fill is gone (assuming you had it int he first place, and if a spec house probably not).

Long-term Swedish studies of European manufactured windows found that after exposure of "10-20 years of the Danish climate there was practically zero gas loss. The lifetime and durability of gas-filled units can therefore be said
to be the same as that of ordinary air-filled sealed glazing units." (Some brands performed better than standards and some less.)

What "fair" evidence do you have that Anderson Windows have all failed over the same period?