Double glazing buyer’s guide
- Choose a style to complement your home
- Look for energy ratings on the windows
- Enquire about security upgrades
Replacing windows on your property can change its visual
appearance considerably. It’s important to select
a style that matches your property and enhances its looks,
especially when fitting PVCu and aluminium designs to older
properties. It often helps to look at similar, neighbouring
properties to compare the effect of various replacement
Planning permission is usually only required in the case
of listed buildings and conservation areas or if, for example,
you are converting a flat window into a bow or bay window.
If in doubt, check with the planning department of your
Ensure that you will have an adequate numbers of opening
windows. Some salesmen offer designs with very few openings.
The simpler the design and the fewer the openings, the
cheaper the windows will be. But the cost might end up
higher than you think as inferior windows can turn out
to be a bad investment and even lower the value of the
property. It is not unknown for potential property buyers
to negotiate a reduced price on these grounds.
When buying PVCu windows you should enquire whether the
windows are fully welded or whether some parts (transoms/midrails)
are mechanically fixed. Mechanical fixing is generally
a cheaper way of manufacturing and it is possible with
wear and tear, especially on doors, that the mechanical
(screw) fixing will split apart, weakening the frames and
While mechanical fixing is not necessarily a bad thing – especially
if done correctly – preference should be given to
fully welded structures, particularly if all other elements,
such as price and quality of supplier, are similar.
The only exception to this might be for woodgrain-style
PVCu frames when a mechanical fixing can look neater – especially
with regard to how the ‘grain’ finish on the
PVCu frames ‘runs’. Your potential supplier
can give you a detailed explanation of this.
When choosing your windows, look for the energy-saving
recommended logo. Like electrical equipment, window products
are assessed on a rating of A to G, A being the most efficient.
The assessment is based on the whole window, not just the
glass or seals, and the grades are issued by the British
Fenestration Ratings Council.
Fitting double-glazing in replacement windows will provide
some insulation from noise. However if your primary motivation
for fitting double-glazing is to reduce sound then secondary
glazing, in which a new single-glazed frame is fitted in
front of the existing (prime) window frame, will be more
effective. The greater the gap between the two panes, the
better the sound insulation.
Similarly, although double glazing will reduce heat loss
through your windows by an estimated 10-12 % so you will
save money on your heating bills, it will be a considerable
time before you save enough money to recoup the cost so
it is not worth fitting double glazing for this reason
It is prudent to enquire about the type of locks and security
features being fitted to your windows and doors. Most modern
double-glazed replacement windows feature multi-point,
espagnolette-type locking, which will also lock partially
open in a ‘night vent’ position.
It may be possible to upgrade to shoot-bolt locking or
SAC bolt locks for additional security. Options for doors
include the ‘Entry Guard’, a type of security
chain that allows you to partially open the door and view
visitors. Always enquire what comes as standard and what
upgrades are available – it is often the case that
for a little extra cost you can have a substantially better
There is much debate about internally-beaded windows versus
externally- beaded windows on PVCu units. If the beads
holding in the glass are on the inside of the window it
will be more difficult for a burglar to remove the glass
and enter your home. However, some suppliers of externally-beaded
windows will fit special glazing gaskets and double-sided
tape to the frame and sealed unit in order to improve the
security – some claim this elevates the security
levels to those associated with internal beading.
Always ask if the windows have any special ‘easy
escape’ or ‘fire escape’ features. Special
hinges can be fitted to help with this but these are not
usually standard items and will increase the cost. Don’t
be tempted to skimp on this, though, as compromising on
safety features is a false economy.
Finally, ask your supplier who will be responsible for ‘making
good’ around the new frames when they are fitted.
Most suppliers will include this as part of their work
- but you should check.
PVCu French doors in an arched style.