This means that, with certain exceptions for listed buildings and conservation areas, replacement windows must be double glazed. The dilemma for the period property owner therefore is no longer whether to fit double glazing, but how to do so sympathetically. The answer could lie in the greater availability of slimline double glazing units which are able to replicate the originals in appearance whilst offering all the thermal efficiency and sound reduction of standard double glazing.
What are the benefits of slimline replacement windows?
- Authentic look – Slimline units retain the same appearance as the single-glazed originals both from the exterior and interior, making it very difficult to tell that double glazing has been fitted except under very close examination. They don’t produce the “double reflection” of standard double glazing and each pane has a slightly different reflective quality, just as the original glass would have done, so they don’t compromise the period look or feel of your property.
- Efficiency – Advances in slimline double-glazing means it can now match or even exceed the heat-saving properties of standard double glazing. It can achieve a U-value of as low as 1.2, depending on the type of gas used to fill the unit. The U-value is a measurement of heat loss - the lower the value, the more efficient the unit.
- Ease of replacement – Standard double glazing units just imitate the look of period windows by using moulding on both sides of the glass to give the appearance of individual panes, which means that any damage makes it necessary to replace the entire window. With slimline versions, it is only necessary to replace the broken pane, just as it was for the original windows.
- Growing support – Slimline double glazing is gaining favour with conservation and planning officers as the preferred choice for replacement windows in period, listed and conservation properties.
- Availability and cost – The difference in cost between slimline and standard double glazing has come down significantly in recent years, making it a more affordable choice than in the past. Its more widespread use also means that experienced fitters are now much easier to find.
Slimline double-glazing is suitable for most different types of windows, and, unlike standard units, can be retrofitted to some original window frames. All of this makes it an increasingly popular choice with period property owners looking to renovate their period property and including replacing their windows who want to achieve energy efficiency without any detrimental effect on the appearance or value of their homes.