What Is U-Value and Why It’s Important
When choosing new windows, rooflights, or skylights for your home, you’ll often come across the term U-value. It’s one of the most important measurements to understand if you care about energy efficiency, comfort, and long-term savings. Simply put, U-value tells you how well a window or rooflight keeps heat inside your home.
At The Rooflight Centre, our Roof Windows are engineered to achieve excellent U-values, helping you create spaces that are bright, warm, and energy efficient all year round.
What Does U-Value Actually Mean?
The U-value of a window or rooflight measures how well it prevents heat from escaping. It’s expressed in watts per square metre per degree Kelvin (W/m²K) – which sounds complicated, but the rule is simple: the lower the U-value, the better the insulation. Think of it like this:
– A window with a high U-value lets heat escape quickly, wasting energy and money.
– A window with a low U-value keeps the heat inside, making your home warmer and cheaper to run.
For example, old single-glazed windows might have a U-value around 5.0 W/m²K, while modern double glazing can reduce this to about 1.4 W/m²K. High-performance triple glazing can achieve U-values as low as 0.8 W/m²K, providing exceptional insulation.
Why U-Value Matters for Roof Windows and Skylights
Roof windows and skylights are often installed in spaces directly exposed to the elements, such as lofts, kitchens, or extensions. That’s why their U-value plays a critical role in your home’s overall energy performance.
A high-quality roof window with a low U-value will:
– Keep heat inside during the colder months
– Reduce unwanted heat gain in summer
– Lower your energy bills by improving insulation
– Minimise condensation and cold spots
Our rooflights and roof windows are designed to meet – and often exceed – modern energy efficiency standards. By choosing products with excellent U-values, you’re ensuring that your home stays comfortable and efficient no matter the season.
How U-Value Affects Energy Efficiency Ratings
U-values directly influence your home’s Energy Performance Certificate (EPC) rating and compliance with Part L of the Building Regulations. Windows and rooflights with low U-values help reduce your carbon footprint by improving the overall thermal performance of your property. In simple terms, they keep the warmth where it belongs – inside your home.
For example, a loft conversion fitted with high-performance roof windows will retain more heat in winter, meaning less reliance on central heating. Over time, this translates into noticeable savings on energy bills, as well as a more sustainable, environmentally friendly home.
What Is a Good U-Value?
Knowing what counts as a “good” U-value helps you make informed choices. Here’s a quick comparison: – Older single glazing: Around 5.0 W/m²K
– Standard double glazing: Around 2.8 – 1.6 W/m²K
– High-quality double glazing: Around 1.2 W/m²K
– Triple glazing or rooflights with insulated frames: Around 1.0 W/m²K or better
At The Rooflight Centre, our products are carefully selected for their thermal performance. Many of our flat roof skylights and roof windows achieve U-values around 1.0 W/m²K, making them ideal for energy-efficient homes and extensions.
How to Choose Rooflights with the Right U-Value
When shopping for rooflights or roof windows, U-value shouldn’t be the only factor you consider – but it should be near the top of your list. Look for products that combine thermal efficiency with build quality, durability, and style.
Here are a few things to keep in mind:
– Check the full specification: Some manufacturers only quote the U-value of the glass, not the whole unit. The overall performance (including frame and seals) is what really matters.
– Consider your room type: Bathrooms and kitchens may need slightly different glazing to control moisture and heat gain.
– Choose reputable suppliers: A low U-value is only effective if the product is made and installed to high standards.
All of our products are handpicked from trusted manufacturers who share our commitment to craftsmanship and performance. Whether you’re planning a loft conversion or upgrading an existing space, we’ll help you find the perfect balance of energy efficiency and design.
Why Choose The Rooflight Centre?
When investing in a skylight or roof window, choosing the right supplier is just as important as the product itself. At The Rooflight Centre (RLC), we’re more than just an online retailer – we’re the e-commerce division of Lonsdale Metal Company (LMC), a fourth-generation family business founded in 1954. With decades of experience behind us, we’ve built a reputation for craftsmanship, reliability, and outstanding service.
Our rooflights have been trusted on some of the UK’s most iconic buildings, including Buckingham Palace, The British Museum, and 10 Downing Street. We’ve also supplied household names like Rod Stewart, Lord Alan Sugar, and Tracey Emin – proof that our products are chosen by both leading architects and discerning homeowners alike.
But our focus isn’t just on prestige projects. Since 2020, we’ve worked hard to make the same exceptional quality available to homeowners looking to brighten and modernise their living spaces. Every rooflight in our range is handpicked to meet exacting standards for performance, design, and durability.
When you choose The Rooflight Centre, here’s what you can expect:
– Beautiful, high-performance rooflights that enhance your home
– Fair pricing without compromising on quality
– Fast delivery and easy ordering from our online store
– Dedicated support from a team that genuinely cares about your project
This combination of heritage, craftsmanship, and personal service makes us a trusted choice for homeowners
who want a roof window that truly delivers on its promise.
Ready to Upgrade to Energy-Efficient Roof Windows?
A roof window with an excellent U-value can transform your home – improving comfort, reducing bills, and boosting long-term value. If you’re ready to make your property warmer, brighter, and more efficient, explore our full range of Roof Windows here. By choosing The Rooflight Centre, you’re not just buying a window – you’re investing in quality, expertise, and a brighter future for your home.
