Why does condensation form on my windows in the winter?

This depends on the types of windows installed and the relative humidity levels in the home.

1. The condensation is forming on the room side of the glass.

This is caused by a combination of high interior air humidity and a large temperature difference between the window and the indoor air. When warm interior air hits the cold window, it decreases in temperature. Cold air cannot hold as much moisture as warm air, which is why the condensation forms. If the condensation forms in large quantities and runs down the glass, the windowsill or underlying wall materials may become moldy or moisture damaged, and could require repairs.

Remedies for reducing the formation of condensation include:

•  Lowering the humidity (removing plants, hanging laundry, storing wood outside to dry, installing an exhaust fan, etc.)

•  Installing heat sources below windows to reduce the formation of condensation by flowing warm air across the glass.

•  Installing storm windows on single-pane windows, and keeping blinds or curtains slightly away from the windows to allow airflow in front of the windows.

2. The window installed is doubleglazed (two panes of glass separated by a sealed spacer), or triple-glazed (three panes of glass separated by sealed spacers), which is also known as a thermopane window.

The seals between the panes have deteriorated, which allows condensation to form between the panes of glass. Although it cannot be cleaned and is often considered inconvenient to look through, this diminishes the insulating capacity of the window only slightly. However, it is often considered inconvenient to look through. Correction of the problem typically involves having the window replaced.

3. The following are some of the main features that are available in new energy-efficient windows:

• Double or triple-glazed glass (i.e. thermopiles). These are two or three panes of glass manufactured as one window with a very thin separation between the panes. This separation width provides less convective heat loss than the typical separation width of 2-4 inches, which is often observed on standard thermopane or singlepane windows equipped with a storm window.

• Low-E coatings. Installing heat sources below windows to reduce the formation of condensation by flowing warm air across the glass.

• Inert gas fills. Another big advancement in window technology has been the introduction of inert gas fills into the space between the glazings. Argon and krypton are the usual choices, with argon being the most common. Filling the space between the glazing with these heavier gases reduces heat loss due to convection and conduction.

• Low-conductivity spacers. The spacer between the glazing at the perimeter of the window has historically been made out of aluminium, which is not only lightweight and durable, but also provides considerable heat loss. Newer non-metallic spacers are now available to reduce heat loss at this location.

The cost for the inclusion of the energy efficiency features described above varies, but can be 10-15 percent more than standard double-glazed units. However, many window manufacturers are converting their production lines to produce only high-performance units. Some super high-performance windows that are using cutting-edge technology for even more energy savings than those described above are available, but at considerably higher costs.

Proper installation is especially important with high-performance windows because poor installation techniques can negate their performance. Installation should be completed in accordance with manufacturer’s recommendations and should reflect current industry standards. Be sure to check out your contractor’s qualifications to ensure proper installation.

Completion of an energy efficiency assessment is recommended prior to upgrading in order to determine the feasibility of upgrading windows.

Contact AmeriSpec Inspection Services to learn more.

This article appeared as a newsletter from AmeriSpec Inspection Services in December of 2015.

Improve your home’s heat retention! (Image courtesy of Wikipedia)

Retain heat this winter with these 5 fast tips

Saving energy –and especially, saving money—is a priority for most homeowners during the winter months. Every time the furnace starts humming, we get an audible reminder that a little more of the paycheck just went up in flames to keep the frigid outdoor temperatures at bay.

Because so much of the year is spent in uncomfortably cool temperature ranges, Minnesotan homeowners have more time to reap the benefits of efficient heat retention strategies. Fortunately, you won’t have to break the bank or spend all your weekends updating your house. Here are five tips that will keep your home warm this winter for less:

1. Update Door Weatherstripping

This is a fast, inexpensive way to stop heat from escaping your house, and for keeping heat out in the warmer months, too. Weatherstripping is the soft, spongey bumper that runs along the threshold of exterior doors and windows. It forms a seal between the closed window or door and the threshold’s trim. The rubber-like material can break down, crack, or come loose from the threshold over time, which lets warm air out and cold air in. Replacing weatherstripping is simple: just pull off the old, and stick on the new! You can find replacement strips at a hardware or home improvement store.

2. Seal up the Fireplace

If you aren’t using your fireplace, seal it up!
A traditional wood-burning fireplace is a heat drain when not in use. If you can’t sit near the fireplace in winter without throwing on a sweater, you’re losing heat up your chimney! While closing the damper (also called a “flue”) is a good start, but the thin metal plates don’t provide very much protection from the cold. You can buy purpose-built inflatable chimney plug balloons online and at various retailers for added protection. If you’d rather make something yourself, you can make a cover for the inside of your fireplace from rigid foam insulation board. With some careful measuring and cutting, the foam has just enough flex around the edges to make wedging it above the fireplace and below the damper an easy 5-minute job.

3. Take advantage of Sunlight

Sunlight is one of the most obvious yet overlooked heat sources for homes in the winter. It’s so efficient, that the Mall of America in Bloomington, MN uses sunlight alone to maintain its balmy 70-degree temperature, even in the subzero Minnesota winter. That’s right, America’s largest indoor mall has no centralized heating: just a lot of windows facing the sun! http://www.mallofamerica.com/about/moa/green-initiatives

4. Use your Ceiling Fans

We usually associate ceiling fans with keeping us cool, but they are also useful in the winter months, too. Hot air that might otherwise be trapped near the ceiling can be pushed back down where it’s useful: around you!

5. Let your Vents Breathe

When possible, move your furniture away from air vents. If you have any vents that are obstructed by furniture, shut them off so that the air passes to the next available vent. Otherwise, you’re just paying to heat the pocket of air underneath the couch, which isn’t saving energy!