What is U-value and why is it important?

​​What is U-value? Many of you have come across U-value when looking for garden buildings, doors, windows, or general construction materials. So what is U-value, and what does it mean for you?

U-value explained

Simply put, U-value represents heat loss or gain within buildings, doors, windows, and construction materials.

If you’re looking at the measured U-value of a component or a material, lower means better. Materials with lower U-value retain heat better and offer better energy efficiency, keeping you warm and safe from the elements. A regular brick house with proper insulation has a U-value of around 0.30 W/m²K, and an adequately insulated wooden building can have a U-value as low as 0.20 W/m²K

U-value is measured in W/m²K (Watts per Metres Squared Kelvin).

Proper insulation brings the U-value down

We have ensured that our doors and windows that come with your garden building installation kit have a U-value as low as possible, keeping the heat inside. But when a garden building is not insulated, the heat usually escapes through the walls, floor, and roof. Although wood as a construction material has good thermal insulation properties, it is not enough to keep you warm in the winter months.

Proper high-quality insulation is what makes the difference by bringing your heating costs down and keeping the warmth inside. We offer insulation kits with most of our cabins as an optional extra. If you’re looking to use your new garden building throughout the year, we strongly advise you to add insulation materials to your order.

How significant are the differences between solid wood and insulated walls?

A simple example would be as follows. A regular 70 mm log wall has a U-value of approximately 1.5  W/m2K. Adding 100mm of insulation and 22mm boards to cover it brings it down to about 0.30 W/m²K, which is an excellent value for any building. It is also possible to get the U-value even lower using more insulating material or thicker beams. Still, as the doors and windows usually have a higher U-value, it is not practical for a garden building.

What is the optimal solution for a garden building to be used all-year-round

To give a garden building better thermal insulations properties, we recommend adding 25mm thick insulation boards underneath the floor and 25mm insulation boards + 12 mm OSB boards to the roof.

There you have it, U-value explained!

Please get in touch with us for wall insulation as different models have different constructions and wall thicknesses.

Right now we offer insulation with fitting for those who have ordered garden building installation from us to ensure the best quality possible. If you’d like to discuss a custom solution, get in touch with our customer support!