Why do I have SO MUCH condensation on my windows!?

This is a great time of year to talk about indoor moisture.

Because we keep our houses more closed up in the winter (unless you live in an area that needs a lot of air conditioning and you keep the house closed up year round) moisture can build up in the warm indoor air. Warm air can hold moisture until it reaches saturation and then it will start to give up that moisture to the cooler surfaces around the home.

Take for example this metal screw that attaches the front entryway door pull handle to the face of the  door.  The staining and moisture is because there is way too much moisture in air at the interior of the home and it is condensing on the cooler metal.  It is bad enough that water runs down and stains the door.


While a little fogging of windows is normal during incidental “steamy moments” like when you do the dishes (does anyone besides me really do dishes by hand?).  If you have condensation on your windows to the point that it starts to run down the glass–YOU HAVE A MOISTURE PROBLEM!

Your windows certainly should NEVER look like the one in this picture–all that moisture and mold is in the living space–not between the panes of glass.


You don’t really have to wonder if you have a moisture problem when your windows look like this–you do have a moisture problem. The next thing will be figuring out why and then doing something about it.

There can be SO many causes of excess moisture in a home that it will not be the purpose of this post to go into great detail about the many causes. This post instead will be about what you can try before you call in the big guns to figure out what has gone wrong with your home.

In the majority of cases it is not the house that is the problem at all–it is the occupants of the home and the fact they do not know how to properly operate the home. Some people’s lifestyles are more problematic than others. If you diligently do the things I suggest and the problem does not go away–then you will likely have to consider other causes that are more related to problems with the house itself.

1. Open curtains and blinds at least a little bit every day. While it may waste a little energy, you don’t want the air that gets trapped behind the curtains to give up its moisture to the cold glass. Adequate circulation of air will prevent this. Condensation is especially problematic in bedrooms that people tend to keep cooler and tend to keep curtains drawn tighter for longer periods of time. Anyone that has slept in a tent in the cold is aware of how much moisture our bodies give off when we are sleeping.

Keeping the entire interior of the home at close to the same temperature is recommended as rooms left unheated will collect the moisture out of the surrounding room’s warm air like a magnet.  Because it cannot hold the moisture, it will store it on the windows and the cold walls behind all the storage boxes in the room. For example if you have block-out blinds or Venetian type blinds–leave them raised an inch or two to allow for air flow to the glass.

Take a look at these two pictures.  Same room, same humidity and temperature levels.  The first one is the results of condensation with the blinds closed, the second one with the blinds open.



While there is still a little bit of condensation of the glass, consistent with moisture levels being too high, leaving the blinds open prevents a worse build-up of moisture.

2. ALWAYS, run the bathroom exhaust fan for at least an hour after every shower. If you have a way of warming the bathroom into the upper 70’s for a few minutes prior to taking a shower, the warmer air will hold more of the moisture from showering and can then more easily be exhausted during and after showering. If you have condensation running down your mirror or the bathroom window after showering, you are not using your bathroom properly. And another thing–get rid of those dang water saver shower heads that atomize the water making the water easier to disperse into the air. There are other types of water saver shower heads.

3. ALWAYS, use the kitchen range hood while cooking and for a few minutes after cooking. Always use the kitchen fan when the dishwasher is running or even while you are washing dishes by hand.

4. No Grow-ops in the house—legal or otherwise. A few house plants will not cause a problem if all other things in the home, including the inhabitants, are behaving properly.

5. Make sure the laundry exhaust fan is used while doing the laundry. If you don’t have a laundry fan–consider having one added.  Modern construction would require one. Another thing about the laundry is that if the exhaust duct is restricted enough to increase drying time, more dryer moisture will find its way into the home. Making sure that the dryer is behaving properly is important in maintaining proper moisture levels in the home.

6.  Don’t hang laundry to dry indoors.

7. Make sure that all exhaust fans are functional–just because they turn on and make noise does not mean they are doing the job they are there to do. A simple test is to cover the entire grill with tissue and see if the fan uniformly holds the tissue in place. Make sure you do this test with any doors to the room closed. Doors with inadequate clearances for air to move into the room as the air is exhausted may render the fan non-functional. Improving clearances may be necessary. Another test is to put the tissue on the floor near the bottom of the closed door and then turn on the fan–the tissue should be forcefully sucked into the room away from bottom of the door.  Really tight homes may want to think about whether the whole house has adequate means of bringing fresh air into the home when exhaust fans are operated.  All of this can be further complicated by not having direct vent gas appliances.

8. If you are going to cook and bathe in your home it is imperative that you maintain an indoor air temperature above 65 degrees F. I know we all have energy consumption considerations but if you keep the home at 64 degrees (or areas of your home at 50 degrees) and save $200.00 a year in heating costs and cause $2000.00 in water damage you have not accomplished much in terms of saving money. Health costs may also be affected as keeping homes cooler may result in poor indoor air quality conditions.  This cost/benefit ratio is even worse if we are talking about keeping isolated portions of the home cooler. Just heat your home–it will reward you for it.

So, try these things–if you still have nasty looking windows like in the picture above–call a qualified home inspector or indoor environment specialist to figure out what is going on.

By Charles Buell, Real Estate Inspections in Seattle

If you enjoyed this post, and would like to get notices of new posts to my blog, please subscribe via email in the little box to the right. I promise NO spamming of your email! 🙂

Double-pane in the butt windows

failedseals4Is it just me, or is anyone else sick of seeing failed window seals and the apparent inability of these seals to last more than 20 years? In some cases I am seeing whole developments of houses with windows failing as early as 12 to 15 years due to failure of a particular type of spacer between the two panes of glass.

failed-seal1If the purported energy savings of double pane windows is difficult to defend, it certainly does not pencil out if those windows have to be replaced every 20 years–even if it is only the glass part. Generally speaking, when replacing your windows, they will almost never save you in energy costs, amortized over the number of years the sales person would like you to believe, what the replacement and installation costs of the new windows will be. This of course can vary with energy costs and location and other factors, but generally speaking this is true in relatively moderate climates like Seattle.

failedseals3I think it may be time to rethink the whole notion of double pane glass, sealed units–or units that have special gasses installed in them that increases their efficiency, cost and failure rate.

Surely it costs money and consumes resources to make glass. There are houses a couple of hundred years old with original single pane glass that suffer from the poor condition of wood sashes and exposure—but not from failure of the glass. Glass is pretty dang durable stuff—and it is VERY cheap, being made out of one of the most abundant resources on the planet.

Why not go back to window installations, more like the storm window approach?

failedseal2Several manufacturers’ of windows have, in the past, made (and still do in at least one case—Pella) windows with a removable panel. These windows were quite efficient and easily repaired if damaged. If a kid kicks a soccer ball through a sealed unit window, and only breaks one pane, the entire glass unit must be replaced. If it was a removable panel type window only one glass pane might have to be replaced and thereby having a less serious impact on the kid’s allowance.

The failed seal issue, though, is what really gets me. There are no failed seals in windows with removable panels. These windows could theoretically (sans the occasional soccer ball) last indefinitely and contribute to huge savings in energy and the use of natural resources over the lifetime of the house–or even in reuse beyond the life of the house.

I think it is false economy to think that sealed glass units are saving tremendous amounts of energy over what removable panel windows would save. The more complicated these windows get, with the fancy gases and the triple panes, the more difficult it becomes to justify the costs. It seems that any small amount of supposed savings, that could theoretically be gleaned, could be more than offset by focusing more on whole building air leakage, better use of insulation and slightly smaller windows—not to mention more careful planning of window location. Just not having every window in the house an opening type window would represent a huge savings. They should open where necessary for egress and ventilation. Most houses have many windows that never need to be opened and never get opened—so why are they openable type?.

Another thing that could be done with removable pane windows is that one could have a changeable panel that would allow for reflective coatings in the summer and no coatings in the winter. This would allow for the home to benefit from more solar gain when desired. Windows with reflective coatings can actually increase the heating needs of houses in cold climates by limiting solar gain the same way no coatings increases cooling loads in the summer.

Removable panel windows could also be fitted with insulating blinds that could be used to recoup any supposed reduction in efficiency between the two types. Regardless the arguments, over the long-term life of the house, it seems unlikely there would be any meaningful energy savings by choosing sealed units over removable panel units.

We are fighting over miniscule relative increases in R-value between the double pane windows and the most expensive triple pane windows full of “hot-air” gases. It is better in my opinion to spend money in more productive ways, until someone smarter than me invents High-R Glass–that one can still see through, let’s light in and automatically polarizes itself by season.

It seems that we are making expensive choices to save a few dollars when those same dollars could be spent in ways that could actually provide more long term energy and resources savings.

There will never be a perfect solution as long as we want to get in and out of our boxes, breath in our boxes and have natural light in our boxes. The question becomes one of where to spend our money on offsetting all the compromises.


By Charles Buell, Real Estate Inspections in Seattle

If you enjoyed this post, and would like to get notices of new posts to my blog, please subscribe via email in the little box to the right. I promise NO spamming of your email!

It helps to be as thin as a business card…..


I have always been able to get myself through small openings.

In all fairness however, it helps being small.

I was really surprised the other day though when I was able to turn sideways and slide through a narrow slot next to an improperly installed window pane.

Countering the effectiveness of double pane windows

Countering the effectiveness of double pane windows


Of course if I can fit through there, so can other critters and even water—-not to mention heat loss and/or gain.

Now back to my weight gain program.


By Charles Buell, Real Estate Inspections in Seattle

If you enjoyed this post, and would like to get notices of new posts to my blog, please subscribe via email in the little box to the right. I promise NO spamming of your email :-D