FAQ Category: U-Values

A. The best choice depends on: Energy efficiency goals (Lower U-values = better insulation) Window frame compatibility (Ensure correct thickness fits your frames) Cost vs. performance trade-offs

A. Yes, if a triple glazed unit is squeezed into the same 28mm space as a double glazed unit, it may actually perform worse in terms of energy efficiency.

A. A high-performance triple-glazed unit (TGU) requires two panes of Low-E glass, typically arranged as: ✅ 4mm clear glass / 4mm Low-E / 4mm Low-E ✅ Middle Low-E pane is recommended to be toughened to prevent thermal stress cracking v

A. Most double glazed units (DGUs) in the UK are made up of: ✅ 4mm clear glass / 20mm cavity (filled with Argon gas) / 4mm Low-E glass ✅ Total unit thickness: 28mm This is the industry standard for most uPVC window manufacturers.

A. Not necessarily. While double glazing is undoubtedly better than single glazing, triple glazing does not always outperform double glazing in every situation.

A. The U-value of a sealed unit is determined by the elements that are used to make up the sealed unit. The lower the U-value the better insulation performance of the unit, which is why our customers often want lower U-values, because they are proof of better performing products. Just because a unit is triple glazed, it doesn’t […]

A. For detailed information on our double glazing U-values, visit our website or contact our expert team. At Glasscraft, we are committed to providing high performance glazing solutions tailored to your needs.

A. Customers seek low U-value windows because they offer better insulation, reduced energy costs, and increased home comfort. Higher U-values indicate greater heat loss, whereas lower U-values improve thermal efficiency.

A. Windows with lower U-values contribute significantly to energy efficiency by minimising heat loss. A lower U-value means less energy is needed to maintain a comfortable indoor temperature, reducing heating costs and environmental impact.

A. A window's U-value calculation considers the energy loss through its area and temperature difference. For example, a 1.2m x 1.2m window with a U-value of 1.6W/m².K and a temperature difference of 21°C would lose approximately 48W of energy.

A. Thermal performance is measured by the heat loss through a window, known as the U-value. It is expressed as W/m².K, which quantifies the amount of energy conducted per square metre for each degree of temperature difference.

A. When selecting double glazing, prioritise windows with a low U-value for superior insulation. Look for products that feature energy-efficient coatings, insulating gas fills, and high quality spacer bars.

A. Several factors impact the double glazing U-value, including: The type of glass used (e.g., low-emissivity coatings) The gas filling between panes (e.g., Argon or Krypton) The width of the glazing cavity

A. Double glazing U-values play a crucial role in Window Energy Ratings (WERs), which assess overall window efficiency. The British Fenestration Rating Council (BFRC) regulates WERs, and windows with lower U-values typically receive higher ratings.

A. Improving the double glazing U-value involves using advanced technologies such as low-emissivity coatings, insulating gases like Argon or Krypton, and warm-edge spacer bars. These innovations reduce heat transfer and enhance energy efficiency.

A. The centre pane U-value measures heat loss through the middle of the glass, excluding the frame and edges. This is influenced by factors like low-emissivity coatings and insulating gas.

A. A low double glazing U-value means better insulation and reduced heat loss, which can help lower energy bills and improve comfort. The lower the U-value, the more efficient the glazing is at keeping warmth inside during winter and preventing excessive heat gain in summer.

A. The double glazing U-value is a measure of how well a window retains heat. It quantifies the thermal conductivity of glass and window frames, with lower values indicating better insulation. Expressed as W/m²K, the U-value is a key factor in determining a window's energy efficiency.

U-Values

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