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The Science of Heat Loss: How To Fix Drafty Windows This Winter

4 min read

During Muscle Shoals’ short but chilly winter months, about 25%-33% of a home’s heat loss happens through windows. Unless you address yours, it may mean ongoing drafts, discomfort and high energy bills this season. Read on to learn more about the science, potential causes and steps to stop drafty windows.

Understanding the Science of Heat Loss

Snow covered house with elegant custom entry door and windows

Heat always moves from warm areas to cold ones, so it’s impossible to stop window heat loss when outside temperatures are frigid. But that doesn’t mean slowing heat loss transfer is impossible. Let’s break down three naturally occurring processes that contribute to heat loss.


As indoor air hits colder window panes, some of the glass molecules quickly start moving. The faster-moving molecules transfer heat to slower ones, resulting in warm air transferring out through the glass. While conduction can occur with all solid materials, like window sashes and frames, glass is an especially effective conductor. Technologies like warm-edge spacers help offset this and ensure better energy efficiency and insulation in the long term.


Warm air rises because it’s less dense than cool air. As warm air meets your windows, it can rise between the panes of glass before cooling, furthering heat loss. This also creates indoor air currents that result in chilly drafts and cool spots. Argon gas used between window panes instead of air can cut down on convection.


Glass naturally has high emissivity (or, how much energy it can radiate), so losses regularly occur when interior glass emits heat energy to its colder exterior side. Low-E (low emissivity) glass counteracts this process, minimizing heat loss in the winter and preventing cool air from escaping in the summer.

Identifying and Fixing Drafty Windows

Now that we’ve broken down the science, you can check for indicators of window heat loss, including:

There are several small-scale ways to deal with drafty windows. That said, these won’t always solve core issues or offer optimal results, so ensure your windows aren’t beyond repair before getting started. At the end of the day, only higher-quality window replacements are likely to deliver year-round, low-maintenance improvements.

Here are a few different drafty window solutions.


If your windows have worn or absent weatherstripping, some adhesive-backed V-Seal weatherstrips can stop cold air from entering and warm air from leaving.


All windows have caulking when initially installed, but this loses its effectiveness over time. A caulking gun with weather-resistant sealant can seal small cracks and gaps to cut down on drafts.

Thermal Curtains or Blinds

Thermal curtains and blinds are great for creating an extra barrier. They prevent warm air from escaping and cold air from entering thanks to their honeycomb-style design patterns that improve insulation.

Window Films

Window films can be a straightforward way to improve insulation. When shopping for one, keep in mind that polyester or vinyl options have a higher resistance to heat loss than plastic films. Just note that you’ll need to remove it before you can open your windows again.

Upgrading Your Windows

Window World windows have high-quality materials to counteract naturally occurring heat loss and prevent cracks and gaps from forming. We offer double-glazed windows in your style and budget that deliver:

Reduce Heat Loss With Window World Windows

Stop coping with rooms that don’t feel like they ever get warm. Take the best step to enhance your home this winter with Window World of Muscle Shoals. Get started with a no-obligation in-home estimate to understand your current window issues.