why do i get lots of condensation inside my windows?

Question

even though i have double glazing and central heating

Answer 1

No ventilation. You should have the windows a little open for a couple of hours in the day - and leave them open a crack at night.

Merry Christmas!

Answer 2

The "dew point" has been reached at the window surface. The dew point is that temperature that the moisture in the air condenses out. It's a direct function of the humidity in the air.
Usually, this is not a problem with houses that have older furnaces or gas water heaters without direct venting, because the flame in them demands air to burn, and that air comes in through all the many openings in the envelope of the house, and in the winter, that outside air is quite dry...so the house is ventilated and humidity levels stay low, so there is less condensation on the windows. Often, people need to run humidifiers to add humidity for comfort is such houses.

A good level for comfort is about 45% relative humidity. 30% is too dry for most folks, and 60% is too damp.

There are virtually no windows that are not the "weak link" in your insulation, and won't end up cooler than the wall next to them. Even triple glazed windows are not as good as the average wall...and if it's cold enough outside, and the humidity is high enough inside, the dew point will be reached and condensation will develop on the windows.

So what can you do?
Look for sources of excess humidity. Do you have a vented range hood, or does the steam from cooking stay in the house?
Do you always run the bath exhaust fan when showering? If the duct and backdraft damper on it in good shape? Is the grille clean so it's venting as much as it can? You might consider replacing it with a larger one...if it can't keep the mirrors from fogging up, it's not doing a good job.
Is the dryer vented outside, and not blocked with lint or a defective backdraft damper?
Running any vaporizers or humidifiers? If you have a central built-in humidifer, be sure it's not leaking or malfunctioning..adding more moisture to the air.
Is surface or ground water giving you any dampness in the basement? (taping a sheet of plastic to the floor for 24 hours, and looking for moisture under it is one way to check)
Do you have any plumbing leaks around water meters, water heaters, etc...that are adding moisture to the house?
Does your cold water line sweat? If it does, that indicates high humidity, because that water is about 50F in the winter, which is not that cold.
You could run a dehumidifier if all else fails. I don't like them, because they take quite a lot of power.

Sometimes, increasing airflow around the windows will help, because the windows stay warmer and the moisture will evaporate off.

If you have quaility windows, they can take some condensation with no problem, especially vinyl clad or solid vinyl windows.
Putting a layer of plastic on them in the winter will help a lot, but it's a hassle.

If you address all these things, and you still find the condensation excessive, consider getting an "Air to air" heat exchanger to ventilate the house while saving the heating or cooling you pay for. These units have a heat exchanger in them...they pull in outside air, and preheat or precool it with the exhaust air that is going out. http://www.renewaire.com/for_your_home/index.php

Opening a window is a poor solution, and you should not have to do that.

Answer 3

If the condensation is on the inside of the windows only:
When you heat your rooms any moisture present (created by breathing, bath/shower, laundry, cooking etc) is suspended in the air. Warm air can hold more moisture than cold air, so when the heating turns off overnight the saturated air cools, becomes heavy and dumps moisture on the coldest parts of the house ie the windows. This can be compared to when u take a can of coke out of the fridge and it drips with condensation.
What u can do:

Open windows slightly to allow airflow. This is the most cost affective, but uses more heating energy to compensate.

Keep heating on constant. Will work, but very expensive.

Buy a quality Dehumidifier. These work by removing the damp from the air and it collects in a container which has to be emptied regularly. Not only will this cure your condensation, wet clothing dries quicker, more healthy atmosphere and will reduce your heating bills because drier air is easier to heat.

You really need to take action very soon as the mould and mildew which is created can damage health and cause allergies.

One other possibility is that there is major structual damage, or rising damp, leaking pipes, but this would probably been picked up by now.

Good luck

MERRY CHRISTMAS AND HAPPY NEW YEAR !

Answer 4

The problem in this case is airflow. You need to have sufficient air circulation crossing the windows to carry away moisture before it condenses, which also keeps the inner glass temp slightly higher changing the condensation level. This is why you will find the heating vents in forced air systems are always located according to window/door location. If your airflow is blocked by furniture, drapes, etc, that will contribute to the problem. Bottom line- you need to do something to restore air circulation over the glass areas.

One option is to turn your furnace blower setting to continuous instead of automatic. This is much less expensive than people think and has numerous benefits, including continuous filtration and elimination of stratified air.

Ceiling fans will help in most every such situation, set them to reverse in winter, and run at low speed. This blows air upward at the center, pushing warm air out and down at the walls- over the windows.

I'm a pro design/builder of custom homes, with 30 years experience. I'm not guessing.

Answer 5

It's a common problem in houses with Double glazing. Any moisture, and there is a lot inside the house (up to 23 litres on a wash day!) needs to escape and the only way to do that is open a window..You need to ventilate your house.

Double glazing is so efficient these days that your house become so tightly sealed that the moisture has nowhere to go.

Answer 6

if the condensation is between the two panes of glass then it means that the seal has broken and the glass needs replacing. when the glass is made two panes of glass are fixed together with hotmelt, if the seal is broken then condensation happens. just call a local double glazing specialists, it won't cost much. good luck

Answer 7

It sounds like your HUMDIIFIER is set to high. Turn it down to about 25%. It takes at least 24 hours for it adjust proprly. you did not say where you live so the 25% is a 'guess'n my part. In the mid-west, 35-40% humidity is dry months is normal.
Good luck.............the humidistat is normally located on the side of the furnace.

Answer 8

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Answer 9

i agree with what most say.. other than opening a window.. thats BS.. yes its too much moisture in the house. opening a window is not the only way to remove it. dehumidifer.. and to do some of the other options to help reduce moisture.

Answer 10

Hot air inside + cold air outside will fog up your windows. . .