What Are U-Values And Why Are They Important ?
Everyone wants their homes to be more energy efficient. Not only is it good for the environment because it helps save precious natural resources and reduce pollution, but it’s also good for your wallet too.
But what does being ‘energy efficient’ actually mean? In a nutshell, it means using less energy to achieve the same desired result. For example, while traditional incandescent light bulbs do a great job of illuminating a room, LED light bulbs are now a very viable alternative, using significantly less electricity (energy) and boasting a much longer lifetime.
Another way to use less energy (be more energy efficient) is by ensuring your home is sufficiently insulated, so that it stays cool during the summer and warm during the winter. In fact, when it comes to making your home more energy efficient, insulation is widely considered to be the most practical and cost-effective way.
And that brings us to the focus of this post: U-values.
What are U-values?
A U-value is a measure of how quickly heat transfers through a building material or element of a house e.g. a wall, a window, a roof. In other words, a U-value expresses how good an insulator something is, with the rule of thumb being the lower the U-value, the better i.e. the best insulators have the lowest U-values.
Measured in watts per m² Kelvin (W/m²K), U-values actually need to meet certain standards to comply with building regulations in England.
The table below, taken from Approved Document L1A (link above), shows the minimum energy efficiency standards required in new dwellings:
However, it should be noted that the values shown above are the maximum permitted for each element and the standards for the notional domestic building are considerably higher i.e. the U-values are much lower:
Why are U-values important?
U-values are important because they provide a quick indication of how good an insulator something is. So, for example, they allow consumers to compare products and make an informed purchasing decision.
Moreover, because building regulations stipulate the maximum U-values allowed for various elements of a house, homeowners can afford total peace of mind that they are adhering with current regulations.