A U-Value measures how much heat passes through a specific part of a building under standard conditions. Simply put, it shows how well a material prevents heat from escaping. A lower U-Value means better insulation, as less heat is transferred from inside to outside. To maximize energy efficiency, the aim is to achieve the lowest possible U-Value. Current building regulations require windows to have a minimum U-Value of 1.2 W/m²K.

Double Glazing

• Two panes of glass with a spacer filled with air or gas (like argon) in between.
• Typical U-Value: 1.2 – 2.8 W/m²K (depending on the glass and gas used).
• Provides good thermal insulation and reduces heat loss compared to single glazing.
• Helps with soundproofing, but not as effective as triple glazing.
• More affordable than triple glazing.

Triple Glazing

• Three panes of glass with two insulating air or gas-filled spaces.
• Typical U-Value: 0.6 – 1.0 W/m²K, meaning superior insulation and energy efficiency.
• Better soundproofing due to the extra pane and air gaps.
• Reduces cold spots and condensation inside the home.
• Slightly heavier and more expensive than double glazing.

Which One is Better?

• If energy efficiency and insulation are your priority, triple glazing is the best choice, especially for Passivhaus or low-energy buildings.
• If budget is a concern, double glazing still provides excellent insulation and is often sufficient for UK building regulations.

When you order windows with Glassworx Ltd you will be offered supply only or Installation which is carried out by our third party installers. We use third party installers who are trained and have 

Getting a quote from Glassworx Ltd is quick and easy! You have several options:

✅ Email Us: Send your enquiry to [email protected], and our team will get back to you with a Free detailed quote.
✅ Call Us: Speak directly with our experts by calling 01259 231 222 for advice and pricing.
✅ Visit Our Showroom: See our range of Internorm, DAKO and Qfort windows, doors, and accessories in person and discuss your project with our team.
✅ Online Quote Form: Fill out our free quote form on our website with your project details, and we’ll provide a tailored estimate.

Please include Architect drawings or window schedule if you have these prepared already. 

No matter which option you choose, our team is here to help you find the best solution for your home or project!

It’s important to consider your glazing requirements early in your project. A common mistake is leaving glazing decisions until the last minute, which can lead to delays due to underestimated lead times for surveys, ordering, and manufacturing of windows. To keep your project on schedule, we recommend reaching out to us as soon as your opening sizes are available. This allows us to coordinate with your timeline and ensure a smooth process.

HF and KF systems are in reference to Internorm window products.

HF stands for Holz Fenster (German for Wood Window) This is Internorm’s Timber Aluminium Clad option, such as HF410, HF510. Then you have HS which is Holz Schiebetür which translate to Wood sliding door. HS330 is Internorm’s Timber Aluminium Clad sliding door option. 

KF stands for Kunststoff Fenster (German for UPVC/Plastic window) This is Internorm’s UPVC Aluminium Clad option, such as KF410, KF510 and KF520. Then you have KS which is Kunststoff Schiebetür which translates to UPVC sliding door. KS430 is Internorm’s Upvc Aluminium Clad sliding door option. 

We are based in Central Scotland, near Stirling. 

Unit 4a, The Cow Shed, Farm Business Park, Block 4 Manor Steps, Manor Loan, Stirling FK9 5QD.

If you are interested in a showroom appointment give us a call on 01259 231 222 or email us on [email protected].