Condensation on Home Windows

I wonder if this would help?

http://www.rainx.com/Products/Windshield_Treatment/Anti-Fog.aspx

I suspect these new window have sealed the home up tight and there is nowhere for the moisture in the air to escape. Comes from cooking, bathing and even from us breathing. You may want to look at putting exhaust vents in the bath and kitchen to help remove some of it.

This condensation is across the whole surface or around the edges? A lot of the older windows used aluminum extrusions to space the glass apart before it was seal. It conducts heat. So it can leave a cold edge around the perimeter that will cause condensation. The newer windows have a warm edge spacer that does not. Windows with IGUs (insulated glass units) with the old spacer will not pass Energy Star tests here in the US. How old are the windows? Did they meet Energy Star standards?

Good post, good points.

The OP should follow your post carefully and also:-

Everyone should open the windows and replace the house air at least once a day.

How long to open? depends on wind speed, temperature differences etc...

Remember that cooking, animals, bathing and people breathing load the air with moisture, look at a humidity meter to find out how much.

Somewhere between 40 - 60% is usually comfortable....less or more not!

If you keep your curtains closed, I've seen people use these tubs, placed on window sills. They work well.

http://www.damprid.com/

There are two potential causes: 1) high humidity inside the house and 2) a poorly insulated structure. The cheapest solution is to reduce the humidity inside the house with a dehumidifier. But I also recommend you carefully inspect the windows and external doors to see whether the frames are conducting too much interior heat to the outside or if there are cold air leaks. You may have new double pane glass windows but how well are the walls,ceiling and doors insulated?

Whenever there is a difference of temperature and pressure of water vapour across a structure, conditions may develop that lead to a condensation of moisture. Check the infiltration air quantity. Condensation on a structure/window in an air conditioned area, generally, may be corrected by the following methods.

i) Increase thermal resistance of walls, roofs and floors by adding insulation with vapour barriers to prevent condensation within the structures.

ii) Increase the thermal resistance of glass by installing two or three panes with air space(s) between. In extreme cases controlled heat, electric or other may be applied between the glasses of double glazed windows.

iii) Maintain a room dew point lower than the lowest expected surface temperature in the room.

iv) Decrease surface resistance by increasing the velocity of air passing over the surface. Decreasing the surface resistance increases the window surface temperature and brings it closer to the room dry- bulb temperature.

If the frames of the widows are made up of with wood please check that the wooden frame is to be designed such that it includes positive drainage and ventilation to the perimeter of the glass and Plastic spacers to be placed so that it separates sealed glazed unit from the wooden frame.

Open the window every once a while to let fresh air! This works quite well. Technically you have all the other options. But this one is CHEAP!

hte!

As was previously stated, condensation occurs when the temperature of the window glass falls below the dew point of the air it is in contact with. There is no other reason. Opening the windows periodically may help if the dew point of the outside air is lower than the dew point of the inside air. If this is not the case, the problem will get worse. You must either raise the temperature of the glass, reduce the dew point temperature of the air , or both.

Check your heating system - the flue in particuliar if you have an 80% furnace or boiler. Exhaust gases have a high level of moisture - water vapor being a product combustion.

Although your eyes would probably be burning it is worth EVERYBODY knowing the signs. A burning match held near (1/2" or so) the draft hood of a furnace or hot water heater should move slightly toward the exhaust gases moving up the flue.

If it goes out (starved for oxygen), shut the appliance down and call for help, or at least pull the connector apart and inspect the flue up through the chimney with a mirror or from the top down with lights.

I went on a routine "clean and check" the other day and, as part of the drill did this exact test. I was caught by surprise when the match went out! My CO tester was sitting on the top of the boiler running and was only registering 1 PPM!

After the boiler had run for a while the lady of the house said she thought her eyes were burning a little. Mine were not.

Upon inspection apparently the squirrels had found a hole in the flue liner and tried to plug it!. There was motar, bricks, scraps of carpet, insulastion, and plastic where the connector dumps the exhaust gas into the flue. It was 85% to 90% blocked!

That should tell you that a Squirrel (where is the blessed man??) are not always your friend.......

Stop shooting them or letting the dog chase them around!!!!!

Skwirrel, where are you today?????

Do you have a non-vented propane fire place that you run a lot? The by-products of burning propane are carbon dioxide and water.

We see this a lot with customers who use these fireplaces to heat a confined area in their house.

Remember, since carbon dioxide is a result of burning propane, a monoxide detector will NOT ensure your safety. Use a LP detector and ensure a fresh air source. Although dioxide does not build up long term in your system like monoxide, it will still cause harm or death if confined.

The humidity in your house is to high.

The greater the temperature differential between inside and out, the more problematic it becomes.

Buy an inexpensive electronic RH sensor, for a reading. Close counts. 35%-50% is a reasonable range.

As I do not know your climate and house construction, all I can offer is this: The colder it is outside, the less humidity can be in the house before condensation will occur. Windows are always the first to show it. If you live in a cold climate and use heating, a minimal amount of humidity is required for comfort.

If you chronically have condensation problems, than it is time to ventilate your house. A "heat recovery ventilation" unit might be your solution.

Gasket has blown out somewhere around the double pane window and the inert gas has leaked out, creating the green house effect on the two unsealed panes.

As others have posted, your indoor humidity is too high.

Buy a whole-house dehumidifier to remove the excess humidity.

As previously mentioned many times, the inside humidity is too high.

In winter, I prefer an air exchanger to a dehumidifier. Since the exterior air is much colder than the inside of the house it is most likely dryer and will reduce the interior humidity and therefore the condensation on the windows.

The main advantage will be that the air quality in the house will improve. This will solve many if not all of the problems caused by houses that are too air tight which include: Condensation in the windows, mold growing in the corners, loss of insulation in the walls by water condensation in the insulation, cold and alergies...

As mentioned by somebody earlier, 40-50% Relative humidity is a good range in the winter. Lower levels might become uncomfortable causing dry skin, nose bleed, static electricity... I actually have to add humidity in the middle of the winter as my air exchanger does too good of a job at eliminating humidity on cold days.

When the house becomes too dry, I could shut off the exchanger but I want the fresh air. My exchanger has a heat recovery core that reduces the energy loss. I also exhaust it in the attached garage to "heat" it. (Air intake is from outside) Some people had warn me against this as they said that it would make the cars rust. This is non sense as much more water is brought in the garage by the snow and slush covered vehicles than can come out of the heat exchanger vent. This has been in operation for many years.

Another advantage of controlling the humidity in winter and summer is that my hard wood floors are still nice after 10 years as opposed to others developing wide cracks between the planks. In the summer, the AC prevents the humidity from rising above 55-60% RH in the worst period. I aim for 50% RH all year long with dips to 40% in the very cold days and peaks to 60% in the muggy week or two in the summer.

I built a home in 1985 and had to assure it met R2000 standards in Canada. These homes are built like terrariums where there is limited air exchanges and use high quality double or triple pane windows. The vapour barrier is installed with a continuous seal that is inspected at every phase of construction. Now the only way house air can be exchanged is by using controlled air exchangers and recirculated throughout the house or by opening the windows. Opening windows in the winter is not a very good energy use in a Canadian winter. These houses are much more comfortable and safer than most houses. Today all new houses are installed with air exchangers in Canada. Clean air is exchanged in every room on a continuous bases, so air quality inside the terrarium house is very good. Bathrooms and kitchens are installed with ventilating timers to speed up air exchanges temporarily.

I don't know if you have the duct work installed to support such a system. Once the air exchanges are balanced properly, condensation should not occur on the windows. But as stated by 123rider, if the window blind blinds or curtains are heavy, the area between the blind and curtain can be a zone not reached by the air exchanges. The system works very well and saves energy for heating or cooling. I actually use the windows as a method of monitoring the need for raising or lowering the humidity in the house. If I see humidity on the windows, I can lower the house humidity. The air exchangers are equipped with humidity controls.

Although you thermal windows are "fairly new", they are not likely the "E-Plus" version that has a film which reflects infra-red radiation- reducing incoming heat in the summer and reducing heat loss in the winter (reflecting the infra-red rays back to their source.

This is a good description of the systems for after-market installation (by one of the vendors) which helps explain how they work-

http://www.coolsunlight/sun_protection.html

It is from 3-M, but others also make similar products. This film on you window exterior will reflect heat back to the house and keep your inside window panes warmer, reducing or eliminating the condensation while keeping you house more comfortable and reducing energy usage as well.

It probably qualifies for the US energy conservation 30% tax credit as well.

What do you mean "often wet inside depending on temp differences inside and out"?

IF you mean 'wet' on the room side of the glass - it's more than likely condensate from the temp differences as you wrote. The condensate could be treated by running a de-humidifier during the heating season.

However IF you mean it's wet on the inside of the glass - between the two panels, there's little you can do to fix the problem. The window would have to be removed and replaced.

If there is humidity between the two panes. The IGU can be replaced not the whole window. Most manufactures warranty their IGU(Insulated Glass Units) for a least 5 yrs some more.

I have had the same problem since I built this house, it is very well insulated but initially the lumber was green. We moved in in the winter and you could not see out of the fogged windows that yearwinter because of the condensation.

It is still a problem, partly because of not heating in the summer. As soon as it gets cold outside, the internal moisture that has built up condenses on the glass. Ventilating a bit helps, but it is a recurrent problem. I do find that simple rules about not leaving standing water anywhere (eg dishes in sink) is enough to keep it to a minimum. If you don't observe those rules, it's a lot worse.

It sounds like some surfaces in your house need proper sealing to prevent this......

Varnishing, waxing, painting and the like.

You don't want to many "sponges" in a house......

On the contrary, sealing up will only make it worse. Historically homes built in Canada were never tight (sealed, vapour barrier, etc.). This allowed for a lot of dry air infiltration in the winter. Lack of humidity was a real problem.

Times and building codes have changed. Most homes are now too tight and need ventilation in order to control excess humidity. Too much humidity, along with very stale air, full of organics are the problems of today.

A proper sized HRV is the only way to go.

Did you read the post that I was replying to before replying....? It was nothing to do with the blog, or little......whatever your viewpoint

Then you may better understand the thinking behind my reply.....I was not trying to answer the blog at that point.......

Did you see my last post directed at your previous comments?

Just got home, yes.

It sounds like you need an air exchanger or HRV system. An air tight house in a Canadian climate is best for heating. The R2000 housing is a method of sealing the house. To get certified the contractor needs to demonstrate the capability of the house to withstand pressurization and measured air exchanges that occur (cannot exceed 1.5 exch./hour). Most new houses are constructed to R2000 or better and must be equipped with HRV. They work well for very long times. Mine has been running every winter for 25 years with no glitches (touch wood). They are pricey but worth the money. See my earlier post.

Well, my house was built to R-2000 but does not have an air exchanger - my fault for not understanding the need and having a limited budget at the time. There is some air circulation that occurs by default when the wood furnace is in use, so the most condensation is seen in the autumn transition to the heating season. It settles down during the heating season, but still it will recur if a lot of green or wet firewood has been brought in, or if water is left standing.

I wish I could afford to have an HRV installed, no idea how difficult that would be after the fact.

On further thought, this may be more a condition aggravated by the (lack) of quality in your windows.......

I had new quality windows installed 4 years ago and we have had some cold winters and hot summers since then.

Tonight we have temperatures down around a few degrees above freezing at this time. If I feel the inside pane, it is cooler than the room, but not cold......is yours cold under the same conditions? We may need to measure the temperature and compare.....

There is probably 12 mm or so between the inner and outside pane of glass in my windows (empirically measured).

We NEVER get condensation, ever......not in spring, summer, autumn or winter, not in the kitchen with boiling kettles and cooking. Not even in the bathroom when bathing and showering. Simply NEVER.

Which is how it should be. The inner pane does not get cold enough to condense the air carried water vapour......we usually have around 50-55% relative humidity....

By the way, what humidity levels do you have in the house ? (you do have such a gauge!!)

If you have less than 60% RH and you still have condensation, your window quality is the problem, the glass pane inside is getting too cold.......above 60% RH I could not be so certain......

I don't have anything to measure relative humidity but I think it can be quite high. We have a wetter and also colder climate than you, I think: the RH is often high outdoors and, if windows are open as in summer, inside as well.

We also have a high windchill factor that makes the windows cold and indeed drafty when it's blowing: you can feel the cold coming off the glass when the wind blows (not from any air leaks or gaps in insulation). In contrast, when it isn't windy the house stays perfectly warm although it's cold outside.

Just eyeballing the gap between the panes, it is a bit more than a centimeter so probably the same as yours. They were good quality windows up to the Canadian code, I wouldn't blame them for the condensation. I think, as the others said, it is simply that the house is too tight to air exchange, and a proper heat exchanger would be the ideal solution.

Hi Art:

I think you can get a decent one for about $800.00 but you need to size for your house. Visit a good heating and ventilation shop and probe them. Usually a wholesale shop will help you and may even sell direct. On top of that you will need to tie return air from kitchen and bathrooms to the HRV. You will need timers tied into the HRV, so some wiring required. The air for recirculation can be connected to your furnace ducts (just don't hard connect but use a proximity of about 4 inches. Otherwise the duct work can be noisy). I had that problem 25 years ago but had it corrected in a month or so after using it. You will need an intake and discharge line to the outside and they should be separated by 4 meters or so. Set the fan on your furnace to run continuously and voila you have fresh air everywhere and no windows that fog up because of indoor humidity. Windows can fog up if the seals on double panes are broken. In that case the window must be replaced but it is not a house humidity issue. The HRV units are equipped with heating thermostat (used in very cold weather) to prevent the HRV from freezing. Canadians worry more about these minor details.

Total cost can vary and you may need a tradesman to install it. I would guess anywhere from $3-5K in total. I also assume you have central furnace with duct work. If you DYI it will cost about $2K. You may have a local jobber or handiman who works cheaper and knows what he/she is doing. Talk to the wholesaler and sometimes they can direct you in regard to hiring someone.

Good luck

Kevin

My house has only sigle glass in alumuinum rames that donot stop any draughts, My windows condensate through cold air on the glass.

The condensation can be controled by steam cleaning the glass to remove the grease film that builds up through normal weather conditions. Do not use glass cleaners on the windows as this will put a greasey film back on the windows.

Alternitavly if you use shaving foam on the glass it will stop the conensation. This is because the shaving foam has alcahol in it that cleans the grease film off of the glass.

Try it on your bathroom mirror first.

HOPE THIS HELPS.

Either the humidity in your house is too high, or your windows aren't that great. An air exchanger might be a permanent solution, but it would not be a cheap fix. They are connected to the ductwork in a house and pull the moist air from the return ducts and inject outside air into the heating/cooling ducts. However, as posters already mentioned, running vents in bathrooms and when cooking on the stove and opening windows to circulate fresh air are cheaper alternatives that should also help reduce this condensation.

I agree.

Thats basically what I wrote some time ago.

Condensation only forms when the humidity is either very high on good windows (I have good windows, but I have never ever seen condensation, not even in the bathroom or kitchen), or when its still relatively low on badly made windows......