RG-WS85 Non-thermal break system sliding window

Product Knowledge

What energy efficiency ratings do aluminum horizontal sliding windows typically achieve?

Aluminum horizontal sliding windows typically have varying energy efficiency ratings based on several factors, including the design, manufacturing quality, and specific energy-efficient features incorporated into the window. However, aluminum windows generally have lower energy efficiency compared to other materials like vinyl or wood due to aluminum's high thermal conductivity.

Here are some key points regarding the energy efficiency ratings of aluminum horizontal sliding windows:

U-Factor: This measures the rate of heat transfer and how well the window insulates. Lower U-factors indicate better insulation. Aluminum windows typically have higher U-factors (less efficient) unless they are thermally broken (which means they have a plastic section that separates the interior and exterior aluminum parts to reduce heat transfer).

Solar Heat Gain Coefficient (SHGC): This measures how well the window blocks heat from sunlight. Lower SHGC values are preferable for energy efficiency, especially in warmer climates. Aluminum windows can achieve good SHGC ratings if they have special coatings or tints.

Energy Star Certification: Windows that meet certain energy efficiency criteria set by the U.S. Environmental Protection Agency (EPA) receive an Energy Star certification. To achieve this, aluminum windows often need to incorporate thermal breaks, double or triple glazing, and low-emissivity (Low-E) coatings.

Air Leakage (AL): This measures how much air passes through the joints in the window. Lower values indicate less air leakage and better energy efficiency. Aluminum windows can have higher air leakage compared to other materials if not well-constructed, but high-quality aluminum windows can still perform well.

National Fenestration Rating Council (NFRC) Ratings: The NFRC provides comprehensive ratings for windows, including U-factor, SHGC, visible transmittance (VT), and air leakage. Checking the NFRC label on aluminum windows can give a more precise indication of their energy performance.

What insulation technologies are used in aluminum horizontal sliding windows?

Thermal Breaks: Aluminum frames typically conduct heat and cold easily, which can result in energy loss. Thermal breaks are insulating materials (such as polyamide) placed between the inner and outer layers of the aluminum frame to reduce thermal conductivity and prevent heat transfer.

Low-E Coatings: Low-emissivity (Low-E) coatings are thin, virtually invisible layers of metallic oxides applied to the glass surface. They help control heat transfer by reflecting infrared light while allowing visible light to pass through. This reduces heat gain in the summer and heat loss in the winter, improving energy efficiency.

Argon or Krypton Gas Fill: In some cases, the space between the glass panes in double or triple-pane windows is filled with inert gases like argon or krypton. These gases are denser than air, reducing convective heat transfer and improving insulation.

Warm Edge Spacers: The spacer is the material that separates the glass panes in double or triple-pane windows. Warm edge spacers are made of materials with lower thermal conductivity than traditional aluminum spacers, reducing heat transfer and condensation around the window edges.

Multiple Panes: Aluminum horizontal sliding windows often feature double or triple-pane configurations. The extra layers of glass provide additional insulation by creating air pockets that act as barriers against heat transfer.

Insulated Frames: Apart from thermal breaks, some aluminum window frames may include foam or other insulating materials within their hollow cavities to further enhance energy efficiency.

Weatherstripping and Seals: Properly installed weatherstripping and seals help prevent air leakage around the window sashes, improving overall insulation and reducing drafts.