Blog

Energy efficiency—we’d all love to improve it in our homes. More comfort. Less wear and tear on furnaces and air conditioners. And ideally, a utility bill that doesn’t keep creeping up. Upgrading older exterior doors can absolutely help. But it’s not quite that simple. So what really makes a new exterior door more energy efficient?

You already know the basics: an older door replaced with a newer one will improve energy efficiency. Generally speaking. We don’t need a full post to convince anyone of that. What’s less obvious is why some door upgrades make a noticeable difference and others don’t. Improving energy efficiency isn’t just about buying a “good door.” It comes down to a few key factors working together: sealing air, slowing heat transfer, and installing everything properly.

In this post, we’ll break down three boxes worth checking when choosing a new exterior door (and the team installing it). Get these right, and your new door will look better and perform better. 

1. Air Sealing: Stop Heat From Escaping Around the Door

Heat doesn’t just escape through materials—it escapes through moving air.

When warm air leaks out around a door, cold air replaces it. That’s what makes your entryway feel colder than the rest of the house. It’s also what makes your furnace work harder than it needs to in the winter. 

Air leaks can happen in a few places. The most common culprits are around the edges of the door. But you can also have small gaps between the door frame and the wall, or at the bottom where the door meets the sill.

Don’t see any? They still might be there. The gaps are usually pretty small and sometimes you might not even feel them. But even tiny openings can move a surprising amount of air over time.

Stopping this air movement is one of the fastest ways to improve comfort and efficiency.

A few things really help here: 

• Proper sizing so the door fits the opening

• Consistent weatherstripping that actually makes contact

• Spray foam or sealing between the frame and the wall

2. Insulation: Make Sure the Door Slows Heat Transfer

With all that said about air sealing, heat escapes two ways: through air leaks and through poorly insulated materials.

Even if a door is perfectly sealed, heat can still pass through the door. The door slab itself does still matter. Especially with older solid wood or uninsulated doors. They don’t insulate very well. So while they technically slow air, they don’t slow heat transfer. And that’s important. 

The technical term for this is R-value (you know, just in case you’re looking to impress friends this weekend). It’s simply a way of measuring how well a door resists heat moving through it. The higher the R-value, the better it is at keeping heat where you want it—inside during winter, outside during summer. 

Older solid wood doors have very low insulation value (effectively close to R-1). Modern exterior doors are much better at reducing how quickly heat moves from one side to the other. Thanks in large part to using insulated cores (foam inside the door) and double or triple pane glass. 

Older doors often have single-pane or thin double-pane glass, usually without any insulating gas between panes. Newer doors may include double or triple glazing, Argon gas, and Low-E coatings—all designed to slow heat transfer even further.

Think of it like a winter coat. A windbreaker stops air. Insulation keeps warmth in. When it’s cold out, you’re definitely thankful for both.

A well-sealed door is good. A well-sealed and insulated door is even better.

3. Installation: Bring It All Together Properly

Energy efficiency isn’t just about keeping warm air in. It’s also about keeping moisture out—and making sure everything works together the way it’s supposed to.

Proper installation is really important here. Even a well-built, well-insulated door won’t perform as intended if it isn’t installed carefully and fitted to the actual opening.

Installation affects more than most homeowners realize. It determines whether the door is square and level, how well the weatherstripping makes contact, and whether air or moisture can sneak in behind the frame. It also plays a big role in how the door handles seasonal movement as temperatures and humidity change.

This is also why custom fitting is so important. Homes aren’t standard, especially older ones. They’re usually perfectly imperfect. A door that’s built and fitted to the real dimensions of your opening allows everything to line up properly—from jamb depth to sealing. This way, your new door can actually do its job.

At Niagara Pre-Hung Doors, we treat installation as an important part of the whole system. That means sealing the space between the frame and wall, using properly sized door sweeps and sills to block air and manage water, and setting jamb depths to match the wall thickness. It also means using sills designed to direct water away from the home, not back toward it.

When all of that is done right, your door looks good and performs well, season after season. 

What to Watch For

If you’re thinking about upgrading your exterior door for better energy efficiency, it helps to look beyond the surface. A few practical things to keep in mind:

• Whether the door is properly sealed around the edges (not just snug in the opening).

• What kind of insulation the door itself provides.

• How the door will be fitted and installed in your home (not just how it looks in a showroom).

• Whether details like sills, sweeps, and jamb depth are sized to your actual opening.
  

Ready to Talk It Through?

If you’re curious about how energy-efficient your current door really is—or what options might make sense for your home—our team at Niagara Pre-Hung Doors is happy to help.

When you’re ready, reach out to start the conversation.