U-Factor and SHGC: How They Impact Your Windows

Energy bills and windows – they have something to do with the other. Single-pane, outdated windows let warm or cool air escape from the home and allow solar radiation to enter through the glass, causing the heating and cooling unit to work harder. As it does, it requires more energy, thus raising your utility bill. Not all modern windows are the same: Some are energy efficient while others were designed with lower costs in mind. When it comes to choosing the right windows, it pays to know something about U-factor and SHGC.

What is U-Factor?

U-factor, or U-value, is a term that’s given when estimating the heat loss of a window. Windows with lower values provide greater insulation and heat resistance, helping to keep the interior at the proper temperature and to reduce overall energy costs. Some double-pane and triple-pane windows have a U-factor as low as 0.15 and provide maximum heat-flow performance.

What is SHGC?

SHGC is short for solar heat gain coefficient, a number that represents the amount of solar radiation through a window. It’s measured between 0 and 1; a lower number means less solar heat transfer. Though low glass-only SHGC is good, it’s better to have a lower whole window SHGC for optimal heat balance.

How Do These Values Help Windows?

Think of windows with optimal U-factor and SHGC values as barriers against solar heat gain. In the winter, solar radiation provides free heat for the home. However, it leads to overheating during the summer months and higher energy bills as you continually adjust the thermostat. Older windows lack these energy-efficient measures. Windows with high U-factor values and failing assemblies cause:

• Higher interior temperatures
• Heat and cooling loss
• Heating units to overwork
• Rising energy costs per month

Installing windows with low U-factor and SHGC values remedies most energy problems. In addition, window installers can identify gaps and other cracks around the frame that also lead to heat and cooling loss. They’ll not only install energy-efficient windows but also insulate the existing structure to prevent any future heat loss or gain.

Install Energy-Efficient Windows in Your Home

If you’re always setting and resetting the thermostat, or if you notice hotspots or drafts in a room, it could mean that your windows aren’t doing their job. Not all homes have energy-efficient windows installed to help with solar heat gain, so if you bought an older home, you might want to have a professional installer come by and inspect your windows.

Contact Hunterdon Siding & Window Co. to schedule your free in-home inspection. Our experienced window technicians will inspect every window in your home and test for heat gain and loss. Our new replacement windows can save you up to 30 percent on your heating and cooling costs and improve the resale value of your home.

We service a number of locations, including Bridgewater, so be sure to check out our service are to see if we can make it out to where you are!