Dec 16, 2017 
In a nutshell, when the cost of keeping them exceeds the cost of replacing them would be my answer. Still, there are considerations besides the simple money savings. Windows that are past their natural life, while they might still be functioning as reasonably good insulation for your home, they may have become unsightly because of surface deterioration, both from the interior and exterior of your home point of view. The windows can become jammed because of aging or warping from exposure to the sun and the elements, but still may work efficiently otherwise. You have to decide what the value to have functional windows but that don’t look great and are difficult to open and close.
The big question is, are your windows leaking air?
When a window frame begins to leak air, even in small amounts it can put your home heating system under pressure. Just like a dripping faucet may drain gallons of hot water every day, a faulty seal around a window frame or a multi-glazed set of glass panes can lose a lot of expensively heated air throughout a single day. Space heating, as it is called is usually the biggest drain of energy – and the most costly utility –in a typical household. Add another 40% to the cost of it, and you can see how costs can climb quickly. If your window frames were leaking warm air from the house, it can easily add several hundred dollars to your electricity (or gas) bill during the colder months of the year. A few thousand dollars cost would be incurred easily. Multiply that by say 3 years, and the cost of new windows might be exceeded.
Multi-glazed windows also have a seal. When double or triple-glazed windows are manufactured today, they are not simply two or three panes of glass stuck together with a gap between them. They are filled with, usually, a gas that helps with insulation both in terms of heat and ultraviolet light. It’s also virtually free of moisture which retains a clean appearance because moisture might condense into droplets under certain weather conditions. By the way, a simple way of knowing that the multi-glaze seal is broken is when you see condensation between the panes. This also means its powers of insulation are not as effective as they used to be. If air is getting into the gap either from the outside or the inside, it can become, effectively, a single paned situation at least as far and heat insulation is concerned.
Can you split the window installation into two projects?
It’s often the case that on once side of the house, the window frames are at a later stage of deterioration than at the other side of the house. This can happen because of either too much sun, or too little. In the latter case, a permanently shaded side of your house can accumulate moss and lichen, never having the cleansing benefits of direct sunlight. Direct sunlight can kill off moss and lichen at an early stage, preventing them from taking a hold of that side of the house. Still, too much direct sunlight has the opposite effect in that the constant bleaching of the materials on your house can weaken them in a different way. The key is, of course, to treat all externally exposed materials on your house to the appropriate level of care, both for sun, shade and moisture protection.
If, for example, your front windows are in need of urgent repair, but all the other windows are sufficiently stable for the moment, consider doing the window replacement project in stages. Perhaps by signing up for a window replacement project in two stages, you can get what’s urgent done today, and complete the project – with the same design considerations – a year or two from now.
Window frames are part of the house structure
Windows have become a more important part of your home than they were say two generations ago. Today, a good window frame will offer more structural support for your wooden framed house than was thought necessary two generations ago. They are manufactured under far more sophisticated conditions that in the past. Today, as well as providing insulation, convenience and aesthetics, window frames themselves must be strong enough to contribute to the strength of the house structure, yet flexible enough to bend and flex with a house frame that is experiencing a storm, for example. And at the same time, the window frame can’t flex so much that it snaps a pane of glass within it.
Security – do your aging windows present an opportunity for burglary?
Sometimes a hidden risk with old, failing window frames is that they can be pierced open more easily with something like a crowbar. A would-be burglar might be tempted with the notion of not having to break any glass to enter a home, but instead, simply prying a whole window frame lose. A modern window will be built in such a way that it is far more difficult to do such a thing, and presents a far greater challenge to anyone considering breaking into your house. For that reason, new windows offer extra security, as well as aesthetics and insulation.
Flipping a home, or staying there forever?
The amount of money you can spend on windows can vary by an order of magnitude. “Affordable” homes are often built with the cheaper end of the market products, while people who plan to spend years in their home often spend with the intention of doing the best upgrade to their house that they can afford. To that end, who and when you replace the windows in your home will depend on what you plan to do with your house both today and in the long term. If you are flipping a house, as they call it, you might not get a return on investment if you opt for the higher end window products. A would-be buyer is unlikely to either recognize the superior investment, nor offer more for the house if you did. Still, you probably want to do the right thing, and do a proper job of whatever improvements you add. A house inspector worth his or her salt will spot where you cut corners too deeply, but at the same time, windows must reach Washington State code, which in itself will protect any new buyer of your house, or you, if you plan to stay there.
More next week!
