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You may think all doors & windows are created equal - this is not the case with many different factors all going into the manufacture and production of each item. Here we look at several areas that are worth considering before you purchase.

Glass Rating - BFRC

The British Fenestration Rating Council is the UK’s most trusted rating council for verifying the energy performance of windows and doors. BFRC was founded in 1997 to establish the window energy rating system for the UK, to raise standards and drive performance in the industry.Window Energy Ratings (WER) are an overall value of the energy efficiency of a complete window. You cannot simply get a glass that is 'A' rated and put it in a product to achieve an overall 'A' rating. Energy efficiency ratings are coded by letters between A and G. A is the most efficient, while G is the least efficient.An A- rating would mean the windows don't lose energy as they only let out as much heat as they let in from the outside. However, with an A+ window, it lets in more heat than it lets out. The latest Building Regulations require all new homes to have windows with a minimum ‘C’ WER rating.

U Value / Thermal Performance

U Value U-Factor measures the rate of heat transfer and tells you how well the window insulates. U-factor values generally range from 0.25 to 1.25 and are measured in Btu/h. ft² °F. The lower the U-factor, the better the window insulates.

Hybrid Aluminium / PVCu

When choosing Aluminium doors and windows, choose a hybrid (PVCu/Aluminium) option for the ultimate thermal performance - at least 75% better than standard double glazed aluminium windows. Opting for 44mm triple glazing rather than standard 28mm double glazing can reduce the whole window U-Value rating from 1.3 to 0.8. Triple glazing is ideal for windows installed in exposed locations.


FENSA is a government-authorised scheme that monitors building regulation compliance for replacement windows and doors. Every FENSA Approved Installer, from large national brands to small local companies, is assessed regularly to ensure its standards are continually maintained.FENSA covers the replacement of external windows, doors, roof windows and roof lights in your home, against the relevant Building Regulations. Note that the property must be cited on its original footprint, and the use and size of rooms mustn’t be altered.

Window Guarantee

All PVCu window and door profiles should carry at least a 10-year manufacturer's warranty. This is a common standard among reputable firms.

Lock Rating (Anti Bump and Anti Snap)

Lock bumping is a lock picking technique for opening a pin tumbler lock using a specially crafted bump key, rapping key or a 999 key. A bump key must correspond to the target lock to function correctly.Anti-bump locks work by having more pins and specially made keys, having shallow pin stacks to prevent them 'jumping' up or locks that have programmable side bars and no top pins. Locks that use rotating disks also protect against bumping, keeping your door securely shut.

Lock snapping involves snapping the lock cylinder in two, by applying force, and removing the outside part to expose the lock mechanism. Thieves use tools like hammers and screwdrivers to snap the locks and, worryingly, it can take just seconds to gain access.

For example, Yale’s new Platinum 3 Star Cylinder is ideal for properties with PVCu or composite doors. It is anti-snap, anti-bump, anti-pick and anti-drill. It is also TS007 compliant and has been independently tested by the BSI (British Standards Institution), to be awarded the British Kitemarked TS007:2014 3 Star accreditation. This means that no additional security door furniture is required.

Internal Beading (Security)

When a frame is described as "internally-beaded" it means that the beading itself is located on the inside of the frame (ie, facing into the room). The "beading " is the part of the frame holding the glass in place, usually a plastic strip at the edge of the glass which snaps securely into the recess. This is done so that the window cannot be removed from the outside.internal glazing bead by nature of the fact that it is behind the glass must automatically make the window more secure because the bead cannot be removed from the outside. The only way it could possibly be removed is by breaking the glass and removing the bead.

Welded Joins

PVCu welds will naturally become better over time however. Polishing is getting better, and much money has been invested in machinery that can create a weld that is almost seamless. Modern welds are a world away from the older generation versions and the very basic products that carry those deep, unsightly welds which really do steal the attention.

Triple Glazing

New double glazing has a U-value of around 1.6, whereas new triple glazing has a slightly better U-value of about 0.8. ... Put simply, triple glazing will make your home that little bit more comfortable than double glazing by keeping the air temperature in your home just a few degrees warmer.Triple glazing reduces heat loss through the windows improving energy efficiency and helps lower heating bills and improves security as triple glazing windows is stronger than double glazing. The extra thickness also helps to reduce noise from outside coming in.

PVCu Quality

The best PVCu windows will have a chambered outer frame and thermal inserts.