Double-Glazed Replacement Windows

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Modern building construction and rehabilitation is concerned with both the improvement of the building appearance and energy efficiency of the structure. The fenestration; windows, doors and skylights; is an area of particular concern because they are the source of much heat transfer through both conduction and convection. A double glazing quote from qualified installers is part of most construction today.

Double glazing is the term that describes a sandwich consisting of two pieces of glass, a separator, desiccant and a sealant that are formed into a hermitically sealed single unit that is glazed into window and door frames. The unit reduces the energy loss through conduction (through the glass) by up to seventy percent, depending upon what type of glass is used. The glass types include: regular annealed glass, low-emissivity, tempered, tinted and a combination thereof. Another option is to fill the interior of the double glazed unit with an inert gas, like Argon. This further lowers the conductivity of the glass.

The energy transfer ratings of glass are as follows: Single glazing, 5.0 Double glazing, 3.0 Triple glazing, 2.2 Double glazing with Low E glass, 1.7 Double glazing with Low E and Argon, 1.2 This means that the heat transfer of the glazing in windows and doors may be reduced by more than seventy percent.

Another area of energy loss through windows is by convection or via leaks in the weather-stripping seals around the operating window sash edges and at the meeting rail where the two sashes come together. The advent of superior weather-seals has contributed greatly to the reduction of convection in modern window designs. The primary weather-seal is of wool pile incorporating a flexible Mylar fin to aid in eliminating air flow around the sashes.

Modern window designs allow for glazing for up to one inch in depth, so coupled with the tighter seal around sashes, these windows greatly reduce energy loss, enough so that they will usually pay for themselves in three to five years by the reduction in energy bills for both heating and cooling. When new windows are installed in a properly prepared opening, modern caulks and flexible sealants are used, thus the entire building envelope is tighter with less drafts and energy loss.

An added value in the use of double-glazed fenestration products is the near elimination of disease producing drafts during winter months. No more drapes or curtains moving mysteriously in an otherwise still room. Noise abatement is another added value. The modern window with double glazing can reduce outside noise by as much as forth percent, making for a more pleasant environment.

The technology that has developed in window manufacture, has improved not only the glazing, but the framing designs and materials as well. Heat transfer through the frame by both conduction and convection has been nearly eliminated by the use of tighter designs and non-conductive materials. PVC, polyvinyl fluoride, has become the material of choice for residential buildings. PVC is non-conductive and much easier to fabricate into custom sizes than wood, aluminium or steel. Further, PVC requires no maintenance and is very attractive.

The selection of double-glazed window units for building upgrades is smart. Not only do the new windows look great, but they will save energy expenditures, even paying for themselves by this savings. They reduce illness-producing drafts and provide a quiet atmosphere for any home or office. A double glazing quote is good business.

Martin Troughton is an expert in the home improvement field. If you are searching for a double glazing quote or want further information regarding a home improvement related service please visit

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