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Prevent Draughts

Thermal Insulation - Reduce Heat Loss by up to 65%
Get a Quote

Prevent Draughts

Thermal Insulation - Reduce Heat Loss by up to 65%
Get a Quote

Warmth is a valuable commodity and creating a second barrier to the elements is an ideal way to reduce wasteful thermal heat loss. In fact, there are few better ways.

Are you losing heat? Reports show that up to 10% of heat is lost through your windows. Installing secondary glazing adds an extra barrier to prevent heat loss.

As secondary glazing is often fitted with a 150mm – 200mm cavity from the primary window, the air filled cavity acts as an insulator. The creation of an insulating layer of air is as important to the retention of energy as the fitment and seals. With the right glass, the result can be a reduction in heat loss by as much as 65 percent.

For thermal insulation, low-E glass is often the best choice because the glazing has been designed and engineered to provide:

  • the very best single glazing insulation
  • maximum energy conservation
  • an extremely discreet installation
  • an environmentally friendly solution
  • an affordable investment with quick returns

Low-E glass has a transparent coating that is much thinner than a human hair. This coating has been specifically designed to reflect heat back in to the room, reducing heat loss through the window and energy consumption. Studies suggest that secondary glazing installed to single glazed units save up to £75.00 per annum.

Secondary Glazing is the product of choice for traditional buildings and properties, listed buildings and conservation areas, maintaining their appearance, character, integrity and value.

The thermal image below displays houses which have secondary glazing installed. Secondary glazing has been installed to the windows within the white box. As these windows are purple in colour we can see that less heat is escaping through the treated windows.

Our test results highlighted that a timber window has a U Value of around 4.7 W/m2K. A sealed secondary glazed unit can yield a lower U Value of 0.97 W/m2K.

Secondary glazing has been installed to the windows within the white box. As these windows are purple in colour we can see that less heat is escaping through the treated windows.

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Horizontal Sliders

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Hinged Casements

Hinged Casement

Lift Out Windows

Fixed Windows

Fixed Windows

Bespoke Design

Bespoke Design

What is a U-value?

U-values measure how effective a material is as an insulator. U-values are a measure of the rate of transfer of heat through a material. The lower the U-value the better the material is at retaining heat. The installation of secondary glazing acts as an insulator barrier and can reduce heat loss through the window by up to 65%.

The installation of secondary glazing can:

  • Reduce heat loss
  • Minimise draughts
  • Reduces energy bills
  • Decrease noise levels by up to 80%
  • Enhance a buildings security

If you are unsure what glass type is most suitable for your application please speak with our customer care team who will be able to offer more information.

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Fixed Secondary Glazing FAQs

How do I Keep my House Warm?

Having double glazing, or Secondary Glazing installed in your home is an essential way to enhance the thermal efficiency of your home. Secondary Glazing will help to keep your home warm even in the coldest winter months!

How do I Achieve the Best Thermal Performance?

Draughty windows can make a room feel uncomfortable and will result in higher energy costs as heat is escaping. Secondary glazing, with either 4mm, 6mm or 8.8mm Low E glass, can reduce heat loss by up to 65% and instantly prevent draughts. We often recommend the installation of Low E glass as it has a specially designed coating that reflects heat into the room. For optimum performance, we recommend that the secondary glazed unit is face fixed to the interior side of your primary window with an air cavity of no more than 80mm. Secondary glazing will decrease the amount of heat loss when installed with single, double or triple glazed timber or uPVC windows. Here at Granada, we can manufacture our secondary glazed units with or without a hardwood subframe. We advise the installation of a hardwood subframe as this acts as a thermal barrier, preventing the aluminium frame and glass cooling due to the temperature of the fabric of the building. Please speak with us directly where we can advise which type of glass, product and installation type will yield the best results.

Will Secondary Double Glazing Eliminate Draughts?

Secondary Glazing is a great way to eliminate draughts in your home. Not only will your home remain warm against the cold draughts, but Secondary Glazing also helps keep the warm air inside your home. This means you will have reduced heating bills across time! Saving you money!

Will Secondary Glazing Reduce Heat Loss?

Of course! Secondary Glazing acts as a second barrier between your home and the outside. This helps to keep your home warm even in the coldest winter months. Helping to trap the warm air inside, and keeping the cold air out.

What are the Main Benefits of Secondary Glazing?

Old, single glazed timber windows can leak vital warm air causing draughts leading to increased energy consumption. If your windows are currently underperforming, secondary glazing can decrease heat loss through your primary windows by 65%. To achieve a 65% reduction in heat loss, we advise the installation of 6.4mm Low E glass. Low E glass has a specifically designed coating that reflects heat back into your room. When installing secondary glazing to enhance thermal performance, the best installation type is face fix. Face fixing is where you install the secondary glazed unit to the inside face of the primary unit. To gain the best performance results we advise an air cavity of 80mm glass to glass.

How do I Achieve the Best Thermal Performance?

Draughty windows can make a room feel uncomfortable and will result in higher energy costs as heat is escaping. Secondary glazing, with either 4mm, 6mm or 8.8mm Low E glass, can reduce heat loss by up to 65% and instantly prevent draughts. We often recommend the installation of Low E glass as it has a specially designed coating that reflects heat into the room. For optimum performance, we recommend that the secondary glazed unit is face fixed to the interior side of your primary window with an air cavity of no more than 80mm. Secondary glazing will decrease the amount of heat loss when installed with single, double or triple glazed timber or uPVC windows. Here at Granada, we can manufacture our secondary glazed units with or without a hardwood subframe. We advise the installation of a hardwood subframe as this acts as a thermal barrier, preventing the aluminium frame and glass cooling due to the temperature of the fabric of the building. Please speak with us directly where we can advise which type of glass, product and installation type will yield the best results.

How Can I Prevent Condensation?

Condensation occurs naturally on windows, whether these windows are double or single glazed, whenever moist, warm air, encounters a cold surface. Excellent quality and well fitted Secondary Windows, combined with unsealed primary windows or trickle vents, provide a completely tight, internal seal helping to prevent condensation.

Will Secondary Glazing Stop my Condensation?

Yes! Secondary Glazing can help prevent condensation throughout your home. Their airtight seal means your windows will not suffer from unwanted condensation, no matter what the weather!

How to Minimise Condensation?

Secondary glazing, installed with a trickle vent, can help minimise the level of condensation. The trickle vent aids air circulation within the air cavity, which, in turn, can reduce condensation. Granada can install an acoustic trickle vent which has been specifically designed to support air circulation while preventing noise waves passing through it. A hardwood subframe can act as a thermal barrier, as aluminium is a great heat conductor, the wooden subframe prevents cold bridging from the fabric of the building onto the aluminium. In turn, this can help reduce condensation as the temperature of the aluminium frame and glass is not cooled by the heat of the building fabric. Condensation is caused when hot air makes contact with a cold material and where the air is then cooled, where water droplets appear. Minimising the temperature of the glass within your primary units should help to decrease the level of condensation.

Can you Install Secondary Glazing into a Listed-Building?

Secondary Glazing is an excellent way of improving the performance of your property. If you live or own a Listed Building you must be careful about enhancing and changing the external aesthetics of your property. Installing Secondary Glazing does not make any changes to the external appearance of your home. The second window simply sits on the inside of the frame, creating a second barrier to the outside.

Can you put Secondary Glazing in a Grade II Listed Building?

Secondary glazing is often installed within conservation areas, Grade I and Grade II listed buildings. Its unique benefits include increasing acoustic and thermal performance, thus making it a popular choice within the heritage market. English Heritage advises the installation of secondary glazing, as the installation process doesn’t change the original fabric of the building.

Do you need Listed Building Consent for Secondary Glazing?

Yes, you do! Normally Listed Building Consent is not granted for windows and doors, but as Secondary Glazing sits on the inside of the existing window, it is normally allowed. We recommend you check with your local Listed Building council, and ensure you submit the correct paperwork when making house alterations.