Double Glazed Windows

Double glazed wooden windows

Well maintained wood windows can last centuries. It’s a testament to the refinement and texture of wood that Georgian sash windows are still present in many cities. Windows give character to a building. Their shape, size, position and materials impact not only the external kerb appeal of a property but also the inside. New or replacement windows must attain aesthetics, economy and performance.

Importance of high-quality windows

The decision-making process of windows and doors can be quite overwhelming. Their style, efficiency and quality play an essential role in customer satisfaction. Important details such as the amount of daylight that enters the room through the glass can make a difference in utility bills savings and overall comfort of the house.

Badly insulated windows can lose fifteen percent of the heat inside the house. The U-factor value of a window determines the amount of heat that drifts out through the glass. The lower the U-value, the less heat will leave. With heat insulation comes sound insulation. Double glazed windows can dramatically reduce external sounds.


The glazing indicates how many panes of glass are in the window frame. Double-glazed windows consist of two panes of glass separated by a space filled with air or harmless gases such as argon and krypton that help insulate the window. Marvin offers windows with double strength Low-E insulated glass with argon as standard to maximise thermal efficiency all year-round.

Double glazed windows consist of the following components:

  1. A desiccant: it’s a silicon material applied in the spacer bar to eliminate moisture stuck within the gap
  2. A primary seal: it’s the main barrier to air or moisture transfer into the double glazed unit
  3. The glass: can be Low-E, self-cleaning, acoustic, toughened, laminated or a combination
  4. The secondary seal: it’s the main structural adherent around the outside edge of the window, holding all parts together
  5. The gap: it’s the void formed between the component parts
  6. The gas: it fills up the gap, can be dehydrated air or harmless gas, such as argon, krypton or xenon
  7. The spacer bar: it’s a frame that separates the two panels of glass, creating a gap. It can be aluminium or warm-edge

Benefits and regulations

All products specified for the construction industry in Europe – including double glazed windows – must comply with the harmonised European Norms (hENs) to ensure European standards are met. It is important to ask for the best glass and check hENs standards before purchasing replacement windows.

Windows marked with the CE logo are hEN compliant, which applies to basic float glass, coated glass, toughened glass, laminated glass and energy efficient glass. Although the CE mark is not mandatory in the UK, it is proof of compliance with hENs

Marvin Low-E double glaze

Marvin’s Low-E glass is layered with microscopic coatings that cut UV transmissions with virtually no effect on the clarity or colour of the light that enters your home. Marvin applies a hermetically-sealed system for optimum insulation from heat, cold and sound. When the windows are produced, a low-conductivity spacer is used to separate the two panes of glass. The space between the two panes is then filled with an argon gas blend. This gas blend helps minimise thermal transfer.

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