From Dean Dowd on January 26, 2012 in Energy Efficiency
Modern building materials have come a long way over the last few decades, and with ever-rising fuel costs, energy efficiency has become more important than ever. It is suggested that windows and doors account for up to 25% of your homes heat loss; which means making them as energy efficient as possible will both save you money and reduce your carbon footprint.
It is possible to measure the transfer of heat through your windows and doors, and this measurement is called a U-value. The U-value is the best way to see how energy efficient your window replacements or doors will be. The lower the U-value, the less heat will escape from your home. Recent UK government legislation (passed in October 2010), states that all replacement composite doors and windows must have a U-value rating of 1.8Wm2K or less.
Here in the U.S., a similar stance on energy efficiency is likely soon and there is talk of the energy efficiency tax credits being re-applied to windows and doors later in the year (which makes a low U-value door even more appealing). This makes knowing your U-value from you refrigerator rating all that more important.
U-Value Knowledge is Power
Put simply, the lower the U-value of your door, the more energy efficient it is and the less money you will need to spend on maintaining a comfortable temperature in your home.
How do you know the U-value of a door?
Most door manufacturers offer a detailed U-value report which they send with your door. This means you wont know exactly how energy efficient your door will be, until youve already paid. If you can find a manufacturer who can tell you the U-value of your door at buying stage, you can make wiser decisions and better investments.
Different materials offer drastically different U-values. When you are looking to replace your windows, it is invaluable that you know the U-value before making your purchase. There is no point investing in a new door only to find out when it arrives that it has a higher U-value than the door you already have.
Obviously, your decisions wont be based purely on the U-value level, as style and design are also important, but its important that you know the U-value before you part with your money.
Things That May Affect Your U-Value
1. Glass paneling
Generally speaking, the less glass you have in front doors, the more energy efficient they will be. Many manufacturers allow you to customize your door with different glass and panel features. Ideally, you will want to use a company that updates the U-value of your door as you pick and choose your preferred styles and features. Again, this gives you the information you need to make better decisions.
2. The material of the door
Probably the single biggest determining factor in how efficient your door will be is the materials used to construct it. Below we discuss the U-value potential of the most common door materials:
Hardwood Door U-Values
According to CENsolutions, a typical 60mm-65mm thick hardwood door has a U-value of around 2.5 to 3.0. Although hardwood doors are aesthetically pleasing, they do not meet U-value legislation and offer poor energy efficiency.
Timber Door U-Values
Timber doors are said to be manufactured with the least energy consuming methods. This in itself is good for the environment but does not insure long term energy efficiency. Timber doors offer the poorest energy efficiency levels and it has been said that it would be almost impossible to manufacture a timber door which would comply with a minimum U-value of 1.8W/m2k.
UPVC Door U-Values
UPVC was a massive step forward for home energy efficiency and offer fantastically low U-values. Typically, you will find most UPVC doors meet the U-value legislation of 1.8W/m2k. Its worth noting, however, that much like other doors, adding glass to your UPVC door will lead to a higher U-value and poorer energy efficiency.
Also, remember that although UPVC doors offer low U-values, the plastic materials they are made with can lead to a cheap-looking finish. Practical, but not necessarily stylish.
Composite Door U-Values
Composite doors are manufactured with the most modern materials available, and offer the lowest U-values and outstanding energy efficiency. Unlike UPVC doors, composite doors are available in many different styles and finishes such as glass panelling and wood grain finishes. Composite doors have become increasingly popular as they combine the style and design benefits of wooden doors and the practicality and efficiency of UPVC doors.
This U-value information was brought to you be Nick Williams. Nick works for Yale Door, who manufactures energy efficient, U-value compliant composite front doors. The U-value rating for all Yale composite doors is available prior to purchase through the door configurator tool; each door is delivered with a certificate of U-value compliance.