When shopping for new windows or doors, a term you’ll see liberally used is “energy efficient”. Sometimes, it’s used as a buzzword with little detail provided to contextualise it. But at Palace Windows & Doors Ltd, we want to help Sidcup property owners make informed decisions on what products best suit their needs. So that’s why we’ve looked to provide an in-depth explanation of energy efficiency, specifically what ratings means and how they apply to products like uPVC windows / aluminium windows, aluminium doors etc. Whether you’re in the market for bi-folding doors, sliding doors or an entirely different fixture, the information on this page should prove useful.
Have a question regarding the energy efficiency of our products, or the services we provide in and around the Sidcup area? Call our Northfleet workshop today on 0208 301 4890. We proudly supply and install quality, made-to-order windows and doors to domestic, commercial and industrial clients in Kent.
What does energy efficiency mean?
How effective a fixture is in retaining heat within a property. The energy efficiency of everything from uPVC windows to aluminium doors, bi-folding doors to sliding doors, is down to the quality of its glazing and frame.
Dartford property owners beware – if you have double-glazing and a compromised frame, or single glazing and a quality frame, the negative element will likely outweigh the positive. This is because both the frame and glazing work in conjunction, and both contribute to energy efficiency.
Why should I care about energy efficiency?
The main reason is your energy bill. If heat is escaping your property through windows and doors, you’ll have to keep your heating on for longer and at higher temperatures. In fact, heat loss through windows is responsible for up to 30% of Dartford homeowner’s heating use. But you should also consider your impact on the environment. The less energy you use, the lower your carbon footprint.
How does the ratings system work?
Created by the British Fenestration Rating Council, the Window Energy Rating (REM) system, currently used by all good window manufacturers including ourselves, takes into account three different values. The first value is thermal efficiency, or U value. This measures heat loss in watts per sq/m of material.
The test sees an outside temperature 1 degree lower than the internal temperature, using the equation W/m2k. Modern aluminium windows, aluminium doors and even uPVC windows/doors can reach a U value as low as 1.4W/m2k. when fitted with double glazing. Compare this with the average Dartford property’s single glazing U value of 4.8W/m2k to 5.6W/m2k.
Solar gain is the second (G) value. This shows how effective glazing is at harnessing the sun to naturally heat the inside of your home. The higher the number, on a decimal scale between 0 and 1, the better it is. Some of our Dartford clients have expressed concerns over high G value bi-folding doors / sliding doors actually causing a room to overheat. This is rarely an issue. It’s Britain after all! Triple glazing actually reduces G value, so if you’re extremely sensitive to heat then this could be a good option.
The final (L) value is air leakage. This rates the quality and effectiveness of the unit’s seals. Modern aluminium windows, aluminium doors, uPVC windows etc. should be completely airtight. This would result in a value of zero. Anything above zero represents a problem, and should lead to repairs or replacement.
What kind of glazing is most efficient?
Double-glazing is mandatory for any Dartford homeowner looking to make their property energy efficient. This is because between the two panes of glass of a unit, there is argon, krypton or xenon – which have low conductivity and prevent heat from escaping properties.
It’s especially important for sliding doors and bi-folding doors to feature double-glazing, due to the large areas of glass they feature. After all, the larger the glass, the more opportunity there is for heat loss. Some property owners may wish to consider triple glazing, which while more expensive, is even more efficient.
Which frame material is most efficient?
We’re very fond of both aluminium windows and UPVC windows. The former is slightly more expensive, but performs brilliantly in the efficiency department. While uPVC is a cheaper alternative, it’s no slouch. The chambered build of the unit, much like in the double-glazing it features, uses a multi-layered design to create a buffer between the inside and outside of your property.
The same features of each material make them equally suitable for sliding doors and bi-folding doors, or front of house aluminium doors.