Controlling Household Condensation

When you find water droplets forming on cold surfaces you are looking at condensation. If air is heavy with moisture it will form condensation on a cold surface. The cooler the air temperature, the less moisture it will contain. Cooling air raises its humidity. Once the temperature comes to dew point you will find condensation on the cooler surface. It is a major contributor to the growth of toxic mold. Controlling household condensation is important or mold removal may be needed.

Controlling household condensation in a 3-pronged attack:

  1. Eliminate the  cold spots
  2. Eliminate moisture
  3. Lower humidity

Controlling household condensation through the elimination of cold spots

Walls and ceilings

You may get condensation on your walls or ceilings during very cold weather. Sometimes the only way you notice this is by the patch of black mold or mildew growing there. This condensation is caused by inadequate insulation in that area. Sometimes there is a spot that was missed. Maybe the insulation has settled or fallen away. If it is in a ceiling and you have access to the attic, it should be easy to solve the problem. Find the affected area and ensure it gets re-covered by the insulation. If the problem is in a part of a wall, you will have to fill the gap with insulation through the wall. A small hole (or holes) can be drilled into the wall. The insulation can be blown or sprayed in. Then the hole patched and repainted.

Insulate Cold Water Pipes

Insulating cold water pipes is a good measure for controlling household condensation. There are two kinds of pipe insulation. Foam pipes come in several lengths with a slit running along one side. They are incredibly simple to install. Just slide the slit along the pipe to open it and push it on to the pipe. Then slide it into position. At corners and bends notching the pipe will help it fit. Some common bend shapes are also available. It comes in most common diameters of copper tubing. It is very effective at keeping air away from pipes.You can take the added precaution of running duct tape along the slit to seal it completely.

The other kind of insulation for pipes is fiberglass insulation with a plastic covering. It is easier to fit to bends and costs less than the tube insulation. First you wrap the pipes with the fiberglass. Then you wrap the insulation with the plastic vapor barrier. It is not as effective as the foam insulation is.

controlling household condensationWindows

When weather is extemely cold most windows will sweat. However, the better the quality of window, the less likely it will show condensation. Windows with storm windows stand up better than those without. Windows that are double paned have superior insulation than single panes. They are less likely to sweat. Aluminum frames conduct heat/cold more than thermal break or wooden frames. Aluminum frames are more likely to show condensation.

Condensation on windows in high humidity situations is more difficult for controlling household condensation. These circumstances are when someone has showered or when you are cooking (especially if you are boiling food). Using exhaust fans in these high humidity rooms it the best way of controlling household condensation. They stop the humidity from spreading to other rooms.

Toilet tanks

On humid summer days the cold water in your toilet tank will cause humid air to condense. The easiest way to resolve this is to use a tank cover. It will insulate the tank and keep the humid air from coming into contact with it. Sometimes these covers don’t go all the way around the tank. And, lets face it, these covers usually look godawful.

Many new toilets have insulated tanks. Your hardware store may also carry an insulation kit. The kit lets you put poly insulation on the inside wall of the tank. This will keep the porcelain surface from cooling.

Another solution is to install a mixing valve.  The valve ties the hot water line into the cold. The result is filling the toilet tank with warm water.

Eliminate Household Moisture

Controlling household condensation with improved ventilation

For controlling household condensation you can vent air to the outside. Then bring fresh air inside using an air heat exchanger. Use kitchen and bathroom fans to exhaust humidity when you need to.

Seal out the moisture

Houses that have a crawlspace with a dirt floor can cause a lot of humidity. Fully cover the crawlspace with 6 mil poly plastic sheeting. Tape shut overlapping seams. Seal the edges that meet the wall with roofing tile. This creates an effective vapor barrier that should stop a lot of humidity from coming into your home

Lower the Humidity

Heating the room

Relative humidity is reduced in warmer rooms. During winter months heating some spaces like attics and basements will lower humidity.

Controlling household condensation with air conditioning

Air conditioners are not only effective in cooling air but are good at controlling household condensation.They extract a considerable amount of  moisture from the air. It is better continue using the air conditioner throughout the night rather than opening windows. Opening windows will reduce the temperature of some rooms slightly. But the air conditioner will have to work harder the next day. It will have to remove the moisture that was brought in through the window.


When your basement is cooler than the rest of your home it can be quite damp. It will have a high relative humidity if it is cooler than the outside air. To prevent mold from taking hold in your basement run a dehumidifier. Keep it in service until the air in the basement is above the outside temperature.