Save Money With Energy-Efficient Windows

June 28, 2016

In the Des Moines area's continental climate, we need windows that can both block the summer heat and hold in warmth in winter. Today's high-efficiency models do both.

Choosing Your Window Design
Energy-efficient windows are available in many designs, but are usually easiest to find in sliding, casement, and single- or double-hung models. More important than the design is the material used. The glass should be your first consideration. Double-paned models are typically the best choice for efficiency and durability. Models with argon gas added between the panes offer even better insulation and efficiency. In our climate, triple-paned windows provide only slight benefits that usually aren't worth the additional cost. For a cooler home in summer, choose low-emissivity (low-e) glass. This glass is coated with a film that minimizes heat transfer through the windows without reducing light or visibility. Wood frames provide the best insulation, but they're the most expensive and prone to air leakage. Vinyl frames offer a good combination of efficiency, durability, and low cost. Aluminum frames are low cost, but easily transfer summer heat.

Assessing Efficiency
Two ratings are important when looking for an energy-efficient window: U-factor and SHGC. These ratings take into account all features of the window, including the number of panes, low-e coating, and frame material.

  • U-factor - This tells you how well the window insulates to keep you warm in winter. A lower U-factor means greater insulation. In our northern climate, a U-factor of 0.35 or less is preferable.
  • Solar Heat Gain Coefficient (SHGC) - This indicates how much heat the window lets in. A lower number means less heat transfer. Look for a SHGC of up to 0.55 to help keep your home a comfortable temperature year round.
Checking for the Energy Star label will help you find window designs that achieve above-average efficiency. To carry this label, window models that will be used in our climate must have a U-factor of 0.27 or less, while any SHGC is acceptable. For more ideas on keeping your home comfortable affordably, contact us at Lozier Heating & Cooling in the Des Moines area. Our goal is to help educate our customers in the greater Des Moines, Iowa area about energy and home comfort issues (specific to HVAC systems). Credit/Copyright Attribution: "SpeedKingz/Shutterstock"