Every homeowner shopping for windows is looking for energy efficient windows. I should know; I’m the guy you call. So in this article I am going to show you how you can compare windows. What do you need to look for? What questions should you ask? And what are the expectations you should have before you start shopping.
What Makes Windows Energy Efficient?
Have you ever wondered why all the glass-covered buildings in downtown Vancouver have that signature green tint? That is green colouring is multiple layers of Low-Emissions Coatings (aka: Low-E coatings) on the inside of the glass.
There are three pretty important factors that contribute to how good of a thermal insulator windows can be. The frame materials plays a large role, the thickness of the glass used affects heat transfer, and the combination of Low-E coatings change the way that light bounces around. All windows have two primary ratings which I use for to compare windows: “U-Value” is the measure of how well the window passively insulates your home: the lower the number, the better the insulation rating; the “Solar Heat Gain Coefficient” (aka: SHGC) measures how much resistance the window provides to the direct sunlight heating up your rooms: what you need will be case-specific. When discussing how efficient a window is, these are the two primary ways we measure the energy properties of the window.
1. Compare Material Types for Windows
Window glass is primarily double-glazed with a Low-E coating on the inside of the glass. Between the two layers of glass is an inert gas which is usually Argon. As windows have become more efficient, triple-glazed window have taken space in our market. We are combining different Low-E coatings within the glass to magnify their effects. The best energy efficiency ratings come from combining as much building science as we can.
We do not use wooden windows anymore, and for good reason. Wooden windows are very prone to water leakages, air filtration or drafts, and poor seals. They can also quickly deteriorate if proper care and maintenance is not provided. These windows are common in old houses and should be replaced. These are usually only single pane or uncommonly double pane.
Aluminum is a conductor. That means that heat can pass easily from the outside and into your home. The window industry has invested a lot into breaking that connection from the outside. In order to make metal windows that do not directly conduct heat, we have to make expensive windows. Aluminum is ultimately limited in what efficiency rating can be provided.
They meet you in the middle. These uPVC blends have decent structural strength and vinyl is easily reinforced. It is also an inexpensive material to mass produce. So far, vinyl windows are the best at resisting the passive transfer of heat. Vinyl is a very affordable material and is usually the best option for achieving your energy goals. Some manufacturers are able to obtain Energy-Star’s Most Efficient energy rating in vinyl.
Composite systems try to be the best of both worlds. They want to be as versatile and appealing as aluminum, while being the best for energy. Some composite systems are able to obtain the Passive House Certification which is highly coveted in the premium housing market. See our Rehau Window System to learn about the possibilities.
2. Know Your Glass Options
Windows are expensive because glass is expensive. Window improvements across the board come primarily from glass-related innovations. Remember those Low-E coatings that coat the insides of the windows? That coating is silver-based. Depending on the application we may require multiple layers of these coatings. The most efficient windows usually have more glass, more coatings, and larger spaces between the glass panes. If you have three panes of glass and three layers of Low-E coatings, the costs can quickly add up. Glass options are customizable and tailored to exactly your need. Many glass options will change the SHGC of your windows which will impact how comfortable your rooms will be. There are funds available if you are looking at the best energy efficient replacement windows though rebate programs which are federally and provincially available to help you make the best choices.
3. Look for Labels and Ratings
Luckily for you there are organizations keeping us salespeople in check. All windows in Canada are federally regulated. There is a large international organization which tries to make this as easy as possible for consumers. Ask about ENERGY STAR ratings as well as the U-Value and SHGC. Depending on where you live, different climate zones have different suggested energy star windows and they base their recommendations on the U-Value. Energy Star’s most coveted rating is the ENERGY STAR “Most Efficient Window” which few manufacturers are able to achieve. Look for these labels on manufacture websites or on the windows themselves.
4. Know Your Dealer
I know that you can buy windows from a big box store, so you ask yourself, “Why choose A-1 Windows?” We have knowledgeable and experienced staff who make sure that you get exactly what you want and what you need. Windows have so many options that it is unreasonable for the customer to completely know what they are buying. You need to find a dealer that is reputable and experienced. You can also look into their affiliations with other companies, governing bodies, or organizations. Being local also helps ensure that they know your market and will have worked on homes exactly like your own.
5. Lastly, Know the Installers
You need to judge the quality of installers. Who you select determines the quality of the finish. They are the ones who will be in your house and doing the work to install your windows. They are the craftsman who will seal your windows from the outside and create the final barrier that make the windows work properly. Your installers should have input on your window order. They should dictate the installation methods and the final sizing of the windows to ensure a snug fit. Did you know that A-1 Windows has our own in-house installation teams? Well now you do!
That’s All, Folks!
You are now well equipped to start shopping for windows. We have taught you that there are trade-offs when selecting a material and you know the basics of how we make windows more energy efficient. I have spilled the beans! Now, you know how I would approach finding a window supplier and how I would determine if their products were a good fit for my project.