Wood windows fall in the middle of the window frame materials when it comes to energy efficiency. They’re more insulating than aluminum and vinyl, but they aren’t as efficient as fiberglass or composite frames. If you love the look and lifespan of wood windows and want to maximize efficiency, you can upgrade to double-pane or triple-pane glass and consider window tinting and low-emissivity (low-E) coatings to minimize heat transfer.

There are energy-efficient options when building a cottage. Select green building materials, high-performance insulation, and energy-efficient windows when designing your cottage. Options such as solar panels, efficient HVAC systems, and LED lighting can lower your utility bills and reduce your environmental impact. Many builders offer energy-efficient upgrades as part of the design process.

R-value measures an insulation material's thermal resistance, indicating its ability to resist heat transfer. A higher R-value signifies better insulation performance because the material is more effective at slowing heat flow. The R-value depends on the type, thickness, and density of the insulation material, such as fiberglass, foam, or cellulose. Each inch of insulation typically provides an R-value between 3 and 8. There is no single universal R-value; the optimal choice depends on your climate zone. Colder climates require a much higher R-value than warmer ones to maintain energy efficiency, keep the home warm in winter and cool in summer, and manage costs.

There are a few ways to reduce your electricity bills if you use window AC units to keep cool. Set the unit temperature at least 1 degree higher than it is currently to reduce costs. Keep the unit clean for it to run efficiently. You may want to hire a window AC specialist near you to inspect the unit once a year and keep it in tip-top shape.