You may not realize it, but the windows in your home are the weakest link when it comes to energy efficiency. This is why you should strive to get the best windows when you go to build your new home. If you’re remodeling, you should look for the best replacement windows for your home. But in the long run, it’s more than energy efficiency at stake. You should also want a window that will not fall apart in ten or twenty years.

When I first got into the construction business, I worked exclusively on older homes in Cincinnati, Ohio. There were tens of thousands of old homes that had simple up down sash wood windows. These were very common windows in houses built in the late 1800’s and early 1900’s. To this day, thousands of these wood windows are in use and in great shape. The primary reason is the lumber used to build them was old-growth timber that had tight wood grain with lots of dense summer wood in them. Homeowners over the years cared for them and painted them regularly. It’s possible to have windows that last generations.

In my lifetime, I’ve seen a huge shift away from maintenance. Newer materials have become available that have practically eliminated the need to paint windows. Perhaps you’re on the hunt for the best vinyl windows for your home. Vinyl is indeed an attractive material as it never needs paint, it doesn’t rot, and it’s easy to clean. My own home in New Hampshire has vinyl-coated windows.

If you want the best windows for your home, no matter if they’re wood, vinyl, fiberglass, aluminum, or a combination of these materials, you can get them. But the first thing to do is to temper what the window salesman says and stick to the facts. There are two primary independent testing associations that should act as your North Star as you shop for the best window.

The best new windows and the best replacement windows are ones that have been certified by the American Architectural Manufacturers Association (AAMA) and the National Fenestration Rating Council (NFRC). AAMA is the golden standard as they test the actual quality of the materials used to make the window and how those materials are assembled. Their testing is rigorous and random. Once a manufacturer has a window certified, they have to sign a contract with AAMA that allows AAMA to come to the factory unannounced so they can take a window from the assembly line to test. That total transparency works in your favor as the manufacturer constantly must be producing quality windows.

The NFRC focuses more on energy efficiency, so they do testing for air infiltration, R-values of the glass and assembly, etc. To have the best windows possible, you need both certifications. Be aware that the AAMA certification is a special label usually found on the side of the window frame. You can’t see it after the window’s installed.

The NFRC label can be misleading. They’ll install the label on windows that meet their minimum standards, but some windows are much better at saving energy than others. This means you have to be able to interpret the numbers and values you see on the special label. They provide a guide, but it’ll be up to you to determine what the highest values are in the marketplace.

If you’re looking for the best wood windows, not only look for the two labels, but use price as a barometer. The best windows will typically cost more. This isn’t always true, but you can shop feature for feature and see what you discover. More often than not, the higher-priced window will be better. Be sure to factor in support after the sale. That’s really important.

When it comes to the best vinyl replacement windows, be very careful of the sales pitches you might get from a person who visits your home. Don’t fall for any Jedi mind tricks, and ask for written verification that the windows you’re being pitched have the AAMA and NFRC certifications. The salesman may say Yes, but you want to see the letters from the two associations that prove the manufacturer indeed has up-to-date certification. Get it in writing. Remember that you can contact each association to verify that a manufacturer is indeed certified and in good standing.