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

During the lingering cold of Des Moines’ winter months, about 25%-33% of a home’s heat loss happens through windows. Unless you address yours, it may mean ongoing chilly drafts, discomfort and energy inefficiency this season. Read on to learn more about the science behind drafty windows as well as potential causes and ways to stop heat loss from impacting your home. 

Understanding the Science of Heat Loss

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

Conduction 

As indoor air hits colder window panes, some of the glass molecules start moving faster. 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. 

Convection

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. 

Radiation

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 Des Moines during the cold winter months. 

Identifying and Fixing Drafty Windows

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

• Noticeable cold spots around your rooms
• Condensation or frost on your windows
• Increased moisture throughout your home 
• Air leaks, which you can prove by carefully using a candle to see if the flame wavers near windows
• Missing or worn-down insulation 

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. 

Weatherstripping

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. 

Caulking 

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 that counteract naturally occurring heat loss and prevent cracks and gaps from forming. We offer double-glazed windows in your style and budget that deliver: 

• Improved energy efficiency and lower heating costs
• More comfortable rooms with fewer drafts and cold spots
• Protection from harmful UV rays and excess glare
• A cooler, more comfortable home when summer comes around

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 Des Moines. Get started with a no-obligation in-home estimate to understand your current window issues.