How-To : Home Improvement

Many homeowners are hesitant to go with double glazed windows as they are unsure what the benefits are and why they should pay extra for them. However, doubled glazed windows have a number of advantages over single paned windows, and are amongst the more popular “home makeovers” available to a property owner.

First and foremost is their money-saving ability. Double glazed windows are composed of two panes glass with an area of “dead air” in between them (normally filled with a harmless, inert gas like argon or krypton, which have better insulation properties than normal air) that helps increase insulation and keep more warm air inside your home when closed. Due to this, they are one of the most energy-efficient windows available today, and according to many experts and government agencies in Canada, the United States, Australia and Great Britain you can save an average of 25-50% on your annual heating and cooling costs by switching from single pane windows to double glazed windows.

Secondly, as double glazed windows have two layers of glass, they are more secure. Burglars often gain entry via windows due to the inherent security weaknesses in them. However, it is harder for an intruder to enter your home through double glazed windows due to the thicker panes, and it also decreases the chance of shattering if a hard object comes into contact with them, the increased density being able to absorb greater impacts. To make sure double glazed windows are very secure, many companies are installing them with strong frames and added security measures by default, such as hard-lipped security beads and friction hinges. These features alone could save you hundreds of pounds in expenses and insurance.

Naturally, a lot of people are concerned about the expense of installing double glazed windows, however the long term savings and peace of mind they can bring more than makes up for any initial costs involved.

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In our past articles I talked about all the steps required to properly replace your old wood sash windows with energy efficient vinyl windows. I told you how to measure for the new windows. Then we discussed the removal of the wood sashes and parting bead. Finally, I told you how to install, seal, and trim the vinyl replacement windows. But, what if those old windows in your home are made of aluminum instead of wood? Is the process the same? No, it’s not the same at all. So, the next few articles are going to explain the differences between replacing wood windows versus aluminum windows.

When discussing the proper frame style for replacing the wood sash windows, I explained the difference between new construction frames versus replacement frames. When replacing aluminum windows, there is another option we have to consider regarding frame style. It’s called a “retrofit” frame. Let’s go over each frame type. First, we have the new construction frame with the nailing fin. If you choose to go this route, you have to remove the exterior around each window opening, pull out the nails holding the aluminum window to the studs, nail in the new vinyl window, apply flashing, caulk, and re-install the exterior around each window.(I get tired just talking about it!)In addition to being a whole lot of labor, you can run into major problems trying to install the exterior product around each window opening. If your home has stucco, you have to try and match the rest of the stucco. It can be done, but not by you. Even most professional stucco guys can’t get a perfect match. What if you have wood siding? Well, you can cut away 2″ of the siding around each window to get to the nail fin, then you can apply 1 X 2 or 1 X 3 trim around each window. Certainly not as much work as the stucco home, but probably more work than the average homeowner cares to tackle. What if each window is surrounded by brick? Let’s not even go there! You would have to remove the bricks, then re-install them all when finished.

Trust me, you don’t want to replace your old aluminum windows with new construction vinyl windows. You want to use either the replacement frame like the one used to replace the wood sash windows, or something called a retrofit frame, that is popular in the west where stucco is a common exterior. Since the procedure for measuring is the same regardless of the frame style chosen, this article will discuss the proper measuring procedure, and future articles will explain the difference in the installation process for replacement versus retrofit.

If you look at the portion of the aluminum frame that goes around the window opening into your surrounding walls, you will see three separate “legs” that form two pockets. The outside leg and the center leg form the first pocket. Your screen and stationary panel will be in this pocket. The center leg and inside leg form the second pocket, and your sliding panel is in that pocket. Find the “leg” that is the widest on all four sides. When measuring the width, run your tape measure from the widest leg on the left to the widest leg on the right. This should be the narrowest measurement. Then, subtract 3/8″ from that measurement. This is the width of the replacement window. Measure the height the same way. When measuring the height, measure as close to the center of the window as possible. This is especially important on windows wider than six feet, because the top wood header has a tendency to sag over time, making the center of the opening the narrowest. You don’t need to deduct 3/8″ from the height like you did on the width. 1/4″ is fine. These are the dimensions you use when ordering your vinyl window. If you have any picture windows(windows without a vent panel), there will only be two legs and one pocket. You still measure the same way.

Next week I will discuss whether your home is a candidate for retrofit frames or replacement frames…

John Rocco has been installing replacement windows since 1978. To learn more, visit How To Install Windows

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Every year, usually in January, we (Builders Architectural - a top Chicago-based window contractor) receive phone calls from customers who complain of sudden condensation on their windows.

This condensation can be surprising because of its sudden onset and large volume. Condensation is widely misunderstood but actually it is quite simple.

Think of a glass of cold beer on a muggy summer day when you are outdoors. The glass in your hand is dripping water on its outer surface to such extent you might almost think the liquid is actually leaking through the glass.

Unless you are drinking from a practical joker’s dribble glass, leaking glass is probably not the cause. The real cause is airborne water vapor(a gas) converting to liquid when it cools while contacting the cold glass. The water vapor has cooled to its “dew point” and condensed into a liquid.

This happens on your windows during a winter cold snap in the exactly same way.

Lets say you live in Chicago and so far the winter has been moderate. Your humidifier is set at 35-40% relative humidity(RH). One day the outside temperature drops from +30F to +10F.

Suddenly your windows are fogged. In extreme cases water drips down the face of the windows. Left unattended, water can damage window frames and finishes.

Then you call your favorite window contractor and complain that your windows are defective. Chances are they are not. The elevated humidity in your home has come in contact with very cold glass surfaces. The water vapor within the air has changed to a liquid form and is now visible on your windows.

Generally, most windows which are “thermal”- meaning they have insulated glass and either wood frames or aluminum frames with thermal breaks - are designed to function well to a range of +10F exterior and +70F interior, with an interior relative humidity (RH) of 25-30%. If any of these variables change, condensation may result.

Window treatment should help, shouldn’t they?

One of the most surprising aspects of condensation can be that it frequently take place behind fixed, insulated, or tightly fitting window treatments such as heavy drapes or honeycomb-style window treatments.

This is not what one would expect. We correctly think of these treatments as adding insulating value to the house. Why would condensation take place here?

The answer is simple. While it is true that window treatments can reduce the flow of heat through a window opening, there is an unfortunate by-product:

Window treatment prevents the flow of roomside heat from warming the glass surface. Glass surface temperature will cool. An environment may be created for condensation.

While window treatments retard the flow of heat, they don’t do much for retarding the flow of water vapor. You need a fully taped foil or plastic vapor barrier for that.

Remember osmosis and diffusion from high school biology? Of course you do. These forces of nature are playing themselves out on your windows and draperies. To refresh your memory:

Osmosis: The force in nature wherein water naturally migrates from a place of greater concentration to a place of lesser concentration. This is your roomside humidity equally dispersing itself throughout your house.

Diffusion: Osmosis through a semi-permeable membrane. The membrane is your window treatment. Diffusion is also known as “vapor drive”.

What can be done in my home?
# Wipe off the condensation. By doing this, you are physically reducing roomside humidity.

# Open the windows an inch or so. The dry outside air will mix with humid inside air and reduce roomside humidity.

# Lower your humidifier settings to 25% or below.

# Open up your blinds and drapes to a level which will allow the roomside heat to warm the glass surfaces.

# Use exhaust fans during and after showering and cooking.

# If you are painting or drywall taping open the windows to allow moisture to dissipate.

# Look at your clothes dryer. Make sure it vents to the exterior. “Vent-less” clothing dryers can bring large amounts of moisture into living spaces.

It could be the windows too

After excluding non-window sources, look for these possibilities on the windows themselves:

# Weather-stripping not tightly compressed allowing air infiltration into the space. Although we know that air infiltration can actually reduce interior humidity, it can also focus a cold spot on a metal window or glass edge. If there is a cold spot you could see condensation or even frost which could be window related.

# There could be a similar cold spot where caulk is missing at the perimeter of the window.

# Your windows could be single-glazed, where only one layer of glass, rather than two, separates you from the exterior.

Deal with humidity first

Good strategy would be to deal with the living space issues first. If you attack them as we describe above, condensation can disappear in 24-48 hours.

If condensation persists, look to the windows and caulking.

Mark Meshulam is Executive Vice President and Director of Engineering for Builders Architectural, a top Chicago-based window contractor. http://www.buildersarch.com

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