Whether you’re replacing old doors and windows or installing in a new build, it’s likely you’ll have heard about energy ratings and U-values along the journey. You may know that these are important and that there are building regulations around them, but you might not know exactly what a U-value is, what’s included in an energy rating, or how to choose your doors and windows wisely based on the ratings you need to achieve.
Thankfully, our team of knowledgeable experts (our amazing Research and Development team) have lots and lots of information on the differences between an energy rating and a U-value, as well as what’s required from you with current regulations. We’ve removed the jargon and, frankly, put it into understandable English to help you make the right decisions when choosing your Origin Doors and Windows.
What is a U-value?
Put into plain English, 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.
What is an Energy Rating?
Energy Ratings provide an overall rating of how energy efficient a window or door is, taking into account several different factors including the U-value, G-value and air permeability.
What regulations do I need to know for U-values and Energy Ratings?
The building regulations for domestic properties vary on whether you’re replacing existing door and windows or installing into a new build property. Check the table below to find out which one is relevant to you.
Door and Window U-Value Building Regulations
| Property type | Build type | Fenestration type | Location | Max. U-Value |
| Domestic | New build, including extensions | Doors & Windows | England & Northern Ireland | 1.6 W/m²K |
| Domestic | New build, including extensions | Doors & Windows | Scotland & Wales | 1.6 W/m²K |
| Domestic | Replacements | Doors | England & Northern Ireland | 1.4 W/m²K |
| Domestic | Replacements | Windows | England & Northern Ireland | 1.4 W/m²K |
| Domestic | Replacements | Doors & Windows | Scotland & Wales | 1.4 W/m²K |
Door and Window Energy Rating Building Regulations
| Fenestration type | Location | Min. Energy Rating |
| Doors | UK | E or better |
| Windows | UK | C or better |
Does triple glazing achieve a better energy rating?
Triple glazing for either doors or windows doesn’t necessarily mean that they will achieve a better energy rating. It depends very much on the type of glass used. Often, the additional third pane will reduce solar gain (the G-value) significantly, which will ultimately give an overall worse performance.
Are Origin Bi-fold Doors thermally efficient?
Origin Bi-fold Door frames have a polyamide thermal break incorporated into the design, which helps to achieve the lowest possible U-value. In turn, our bifolding doors achieve an energy rating that surpasses the energy rating and U Value required in the UK, making Origin the perfect fit for either new builds or existing properties.
To find out more about how thermally efficient Origin Bi-fold Doors are, we recommend you read this article.
