Sliding glass doors are a great way to bring style and practicality to your home. However, one of the most crucial factors to consider when purchasing a sliding patio door is thermal efficiency, i.e., how effective the door is at containing thermal energy.
This is a pivotal factor for homeowners when purchasing glass doors, and they often want an accurate, simple way of finding out a door’s energy efficiency. This factor is most commonly measured using U-Values. U-Values are used to determine the overall thermal efficiency of a door, and this piece will detail what U-Values are and why they are important.
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Read the definition of a U-Value and how they are measured.
Find out why it is so important to consider the U-Values of a sliding door.
Read about the building regulations for sliding door U-Values.
Read the different sliding doors options available from Origin.
We answer common queries on sliding door U-Values.
What is a U-Value?
A U-Value is the measurement of heat transferred from one side of a window (or door) to the other. The lower the U-Value, the less heat that would be lost through the door or window. Therefore, the better insulated a structure is, the lower the U-Value will be.
Thermal efficiency categorises how effective a door is at preventing heat transfer. A U-Value is the unit given to display this and will measure the amount of heat transferred from one side of a window, or door, to the other. A door that allows a greater amount of heat to transfer through it will result in a higher U-Value, and a door that has much less heat transfer will be reflected in a lower U-Value. Thus, the lower the U-Value, the more thermally efficient the door.
Heat loss can be significantly decreased when a door has a better-insulated structure; for instance, having tougher, sturdier glass panes will stop heat from travelling through or polyamide breaks between the inside and outside of the door or window. This will result in a lower U-Value and a more thermally efficient, and thus ideal, door.
Why is the U-Value of a door important?
U-Values allow homeowners to choose the most energy-efficient doors, and this is extremely important for various reasons.
Firstly, more energy-efficient doors are greatly beneficial to the environment. According to UK Government figures, the domestic housing sector accounts for 2.7 tonnes of the UK’s yearly carbon emissions, meaning that energy transfer through poorly insulated doors is seriously damaging the environment. A low U-Value door with optimal insulation will significantly reduce energy transfer out of the home and into the atmosphere, creating a better, more stable environment.
Additionally, high energy loss is not just bad for the environment, but it’s bad for your living standards too. When the heat becomes more precious in the winter seasons, you will not want a door that is constantly letting large amounts of that heat out. A sliding door with a high U-Value, for example, will lead to longer periods waiting for a home to warm up and quicker times for this heat to fade out. However, with a lower door U-Value, the home will warm much quicker and stay at this temperature for much longer since the heat is not escaping as easily. Therefore, more thermally efficient doors are a much cosier option.
Finally, having low U-Value doors will be incredibly beneficial for your finances. Homeowners with poor energy efficient doors will be forced to use more energy to heat up their homes – since the heat keeps escaping – and this will result in much higher energy bills. Homeowners with low U-Value doors will require much less energy consumption to keep their homes warm, and thus, their energy bills will be lessened.
Building regulations for U-Values
It is important to know the building regulations for U-Values and energy ratings as these can vary slightly depending on many factors.
The building regulations differ depending on whether you are replacing an existing door in your property, or installing one into a new build. For new build properties, doors and windows must not exceed a maximum U-Value of 1.6 W/m²K in England, Northern Ireland, Scotland & Wales. For domestic replacements, the maximum U-Value for doors and windows is 1.4 W/m²K.
Throughout the whole of the UK, each property must abide by a minimum overall door and window energy rating, which takes into account many factors including the U-Value. For doors, this is a minimum rating of E or better, and for windows, a rating of C or better. It is therefore evident that each homeowner must be aware of the U-Value and energy ratings of their doors to ensure they are abiding by their designated building regulations.
The Origin Sliding Door range
Origin offers high-quality sliding doors that guarantee you the best U-Values and most energy-efficient products on the market. The two ranges of sliding doors at Origin are the Artisan Sliding Door and the Patio Sliding Door.
Artisan Sliding Door
The Artisan Sliding Door is comprised of high-quality materials along with a minimal and sleek design. One of its main features, however, is its extreme thermal efficiency. The door comes as a bonded system, meaning the glass and frame come as one bonded unit. This creates a tighter seal between the e-toughened glass pane and the aluminium frame. Compared to other doors such as wooden or UPVC, the structure is not only highly secure, but the aluminium window bonding leaves less room for energy to escape, leading to a door with incredible thermal efficiency. The Artisan Sliding Door has an overall U-Value of 1.4 W/m²K with double glazing, which greatly exceeds building regulations.
Find out more about the Artisan Sliding Door here.
Origin Patio Slider
The Origin Patio Slider is the perfect modern take on a traditional patio door. The door is completely bespoke and comes with three slim sightline options to suit your aesthetic needs. One thing that makes the Origin Patio Slider one of the best sliding doors is its superior thermal efficiency. The door has an extremely low U-Value of 1.3 W/m²K when using triple glazing and 1.6 with double glazing - which is highly unmatched by other manufacturers. Your local installer will source the glass for this system, so work with them to ensure it’s the glass that will offer the right U-Value for you. The Patio Sliding Door is a superior door in regard to thermal performance.
Read more about the Origin Patio Slider here.
Frequently asked questions
Does energy efficiency on bi-folding or sliding doors matter?
Yes. Energy efficiency on any door can significantly affect your bill finances, living standards, and your contribution to a safer environment.
What is an energy rating?
Energy rating is the overall measurement of a door’s, or window’s energy efficiency, which takes into account many factors including U-Values.
Can large glass bi-folding or sliding doors be thermally efficient?
Yes, but it depends on many factors such as structural materials, the strength of the glass, the type of glazing used and the construction of the frames.
Is triple glazing worth it?
Triple glazing, although more expensive than double glazing, can greatly increase insulation and result in more thermally efficient doors, which have many benefits.
How is the energy efficiency of doors measured?
Energy efficiency is the sum of many factors, the main of which is a U-Value – the measurement of heat transfer from one side of a door, or window, to the other.
