Windows are a make-or-break feature of your home, and optimizing the quality of new windows depends on three things:

1. First, you need to recognize efficient windows from wasteful ones before they get installed.
2. Second, you need to know about innovative window features so you can look for them as you shop.
3. And third, you need to understand what a good installation is and how to ensure it happens. Don’t rely on window professionals to handle these issues entirely for you. Some will deliver, but others won’t.

Step #1: Choose Intelligently

Informed window choices have to be based on third-party assessments. Don’t settle for anything less. A Canadian outfit called Window Wise is currently my favourite place to start. They’re in the business of certifying window installers, but they also publish a list of windows that meet two stringent performance standards. Window Wise-approved windows also carry Energy Star ratings that ensure above-average energy performance. The best current designs have triple-pane glazing, argon or krypton gas between panes, non-conductive warm edge spacers between layers of glass, and Low-E coatings that reflect infrared and ultraviolet light.

Step #2: Water Leakage Plan B

It’s easy to install windows badly, and the difference between good and bad remains hidden, at least for a while. While windows are your initial line of defense against water getting into your walls, most homes operate with no “plan B”. If water gets past aged caulking or a failed window seam, it goes right onto the wood framing. Rot is guaranteed.

This is why a plastic drainage pan and waterproof lining around the inside of the rough opening makes so much sense. Marvin Windows’ SillGuard, DamSill, Jamsill and SureSill are four brands I know of. They all work the same way, creating an impervious and sloped surface at the bottom of each rough frame, allowing leaked water to drain out from underneath a window. It’s a little thing, but enormously important should water make its way past a window. And make no mistake, it very well could. So why take a chance?

Step #3: Seal with the Right Foam

Spray foam is the best way to seal the perimeter of new windows and replacements. Trouble is, most types of spray foam in a can also pose a threat. They expand so much that they can bow window frames inward under the pressure, making it difficult or even impossible to open and close them. Over-expansion of foam is why manufacturers developed something called low-expansion foam, but even this doesn’t solve the problem completely when it comes to windows.

What you really need is low-pressure foam, not low expansion. Low pressure types expand just as much as other formulations, but with much less outward force. In tests I conducted on one of my building projects this past fall, low-expansion foam still caused windows to bow inward and bind, even when the window frames were temporarily braced with pieces of wood. Low pressure foam, by contrast, caused no bowing even when perimeter gaps were filled and no braces used.

Low pressure foam is currently a specialty item, so you probably won’t find it in every hardware store. It’s made by a handful of companies, but one brand that’s impressed me in particular is Arctic Foam (877.575.3626). It’s one of the products that stood out in my tests. They make a range of foams, and their window and door sealant is the only low pressure type.

The kind of windows you choose and the installation you get plays a big part of the comfort and efficiency of your home. It’s worth the effort to get them right.