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Answers to our most frequently asked questions can be found below. If you can not find the information you are looking for please contact us

  • About Planitherm

    • What is PLANITHERM?

      new2_diragram_large.jpgPLANITHERM is Europe's leading energy saving window glass that uses an advanced coating to retain more internal heat and to absorb warmth from natural daylight, designed for use in a double glazed windows. That means lower heating bills compared to standard windows but for about the same cost.

      Using the latest technology, PLANITHERM has a unique combination of metallic layers, which reflect heat back into a room, to keep heat within a building. At the same time maximising the amount of natural light coming in. As more heat is retained, it means less is required to warm up the home to the desired ambient temperature, in turn lowering energy consumption.

    • Is the coating on the glass permanent?

      Yes, the coating is permanent and hermetically sealed within the glass unit so will last the lifetime of the window.

    • If PLANITHERM lets the sun in, does it let anything out?

      The glass has a microscopic, transparent metallic coating that reflects warmth from natural daylight to help heat the room, rather than allowing it to escape through the windows. At the same time it allows heat from the sun to pass through the glass to warm the room, meaning it takes less energy to maintain a warm, comfortable home.

    • Is the performance of PLANITHERM proven?

      Yes, the performance of PLANITHERM meets the requirements of class C of European standard BS EN 1096 and carries the relevant CE Marking. For more information, visit

    • Will the coating affect the appearance of the glass?

      No, the coating is completely transparent and microscopically thin. 

    • Is this a new product?

       No, Saint-Gobain Glass has been producing energy efficient window glass for many years and have a wealth of experience in coated products. PLANITHERM has been manufactured in the UK since 2004.

    • Will PLANITHERM make my house too warm in summer?

      PLANITHERM has been designed to provide homeowners with warmer more comfortable homes and improve energy effiiciency. It has excellent thermal insulation whilst maximising the amount of warmth absorbed from natural daylight, saving you money on your heating bills. The actual amount of warmth absorbed through your windows will vary depending on their orientation, size and the geographical location of your home.

    • Can PLANITHERM be used in any frame?

       Yes, PLANITHERM can be used in all types of window frames.

    • Why should I have PLANITHERM installed in my windows?

      There are a number of reasons why you should have PLANITHERM installed in your windows. Firstly, Government Building Regulations require us to use energy efficient products that help to reduce CO2 emissions and protect the environment. PLANITHERM is the most energy efficient window glass available. Using PLANITHERM is an easy and efficient way of complying with these regulations whilst offering a number of other benefits:

      • Free Solar Gain - PLANITHERM uses advanced coating technology to capture warmth from natural daylight to help heat the home
      • Thermal Insulation - The advanced coating reflects heat back into the room, meaning less energy is needed to heat the home to the desired temperature
      • Optimal Window Energy Rating - PLANITHERM combined with virtually any window frame will achieve a Window Energy Rating (WER) of B and an A+ is much easier to reach.
      • Haze & Tint Free Windows - PLANITHERM maximises the amount of natural light into the home, without the haze or tint effects associated with older double glazed windows
      • Eliminate Condensation - PLANITHERM helps to virtually eliminate internal condensation, reducing draughts and cold spots in and around the windows
    • Where should the PLANITHERM pane be positioned in my double glazing?

      Ideally PLANITHERM should always be positioned on face 3 of the double-glazed unit. However, if necessary it can be positioned on face 2 as long as it is facing the cavity and thus protected from the external atmosphere.

    • I have condensation on the outside of my windows, are they faulty?

      Condensation on the outer pane is a common occurrence, particularly at certain times of the year.  Enegy Efficient windows (such as those including Planitherm glass) help to capture heat afrom outside and reflect the heat back into the room.  Therefore it is an unavoidable consequence that the outer pane of glass is cooler than it would have previously been with less efficient or older standard double glazing.  you will now note that your windows with PLANITHERM have helped to eliminate any condensation you had on the inner pane, due to your inner page now being warmer than it may have been with your older windows.

    • Can PLANITHERM glass be used in single glazing?

      Due to the nature of the PLANITHERM coating, the coated side must always be enclosed in a sealed unit. As such, the PLANITHERM range is not available in single glazing.

  • Energy Efficient Glazing

    • I have double glazing; does this mean my windows are energy efficient?

       Of course all old, uncoated, double glazing offers a limited level of heat retention. However, Building Regulations now state that an energy efficient window glass must be used in all replacement windows and a double glazed unit containing PLANITHERM is on average 40% more thermally efficient than standard non-coated double glazing.

    • What does this performance mean to me in real terms?

      By switching from single glazing or old double glazing to any one of the NEW Glazing Options window configurations incorporating PLANITHERM, you can reduce your heating bills, create a warmer more comfortable home, increase home security, reduce noise from outside and reduce the amount of cleaning required! 


    • What is a Window Energy Rating?

      Window Energy Rating (WER) is a system for demonstrating the energy efficiency of a window. The labelling used is similar to those seen on appliances such as a fridge or freezer offering an easy method for comparison. To check a window’s energy efficiency before you buy, look at the energy label. The ratings range from A+ to G with a C-rating being the minimum rating required for compliance with current Building Regulations. It considers three aspects of performance:

      • Amount of heat loss
      • Amount of solar heat gain
      • The air leakage of the assembly


    • What is the carbon footprint of an energy efficient window?

       The carbon used to manufacture 1m2 of double glazing is saved within 3.5 months if replacing single glazing windows. In the case of standard double glazing being replaced by energy efficient double glazing, the time is around 10.5 months.

  • Purchasing Planitherm

    • Where can I buy windows containing PLANITHERM?

      Registered PLANITHERM installers are listed on our website.  Select ‘Find an Installer.’ Simply search by your postcode to view a full list of Installers in your local area.

    • How much more will it cost me to install PLANITHERM?

      The cost of upgrading your windows to ones containing PLANITHERM will vary from one window installation company to another and is also dependent on the window configuration you choose (see our range of Glazing Options for full details of what you can achieve with new windows). It is therefore recommended to get quotes from a few companies and then compare the costs and services they offer. To find a local installer visit our PLANITHERM Installer Network search facility.

    • Does Saint-Gobain Glass guarantee the quality of the work carried out by registered PLANITHERM installers?

      No, installers who fit windows containing PLANITHERM can register on the installer network and have met our network requirements. However, we do not guarantee their work and any queries or issues with your windows should be directed to your chosen installer.

    • How do I know my installer has fitted Saint-Gobain glass in my conservatory?

       Unfortunately there is no way for the glass to be marked due to the large sheet format of manufacture. Due to this, there are two ways to check the legitimacy of the installation. Firstly, Saint-Gobain Glass UK supplies glass labels to customers to attach to the sealed units. If your windows were supplied with a PLANITHERM label then you can rest-assured that Saint-Gobain glass has been installed. Some Glass Processors may choose to use their own labels. If there is no label, and this can be for a number of reasons, you would need to ask your installer for a copy invoice or delivery note from their supplier. You can then use this information to follow the supply chain back to Saint-Gobain Glass UK Ltd. 

    • I can't find my installer on your list of installers

      The installers listed on the PLANITHERM Installer Network have joined a voluntary scheme requiring installers to self-register. If your installer is not on the installer search they may still be installing PLANITHERM. Ask them to supply a copy invoice or delivery note from their supplier that states the glass supplied is from Saint-Gobain Glass. You can then use this information to follow the supply chain back to the manufacturer.

  • Triple Glazing

    • Can any house accommodate triple glazed windows?

      Yes. Triple glazed windows are wider than double glazed windows due to the extra pane of glass and cavity spacing between each pane. They are also heavier due to their composition and require a different frame to support the additional weight, but this does not mean they can only be installed in certain houses. Providing the window cavity is deep enough you can almost always opt for triple glazed windows.

    • Why choose triple glazing over double glazing?

      Triple glazed windows are around 40% more thermally efficient than double glazed windows, helping to reduce your heating bills and carbon emissions. With triple glazing, homes are able to stay warmer for longer and you can expect fewer cold spots and drafts near windows. The extra pane of glass provides a security benefit too.

    • What glass should I ask for in my triple glazed windows?

      For the best solution insist on PLANITHERM.  PLANITHERM is Europe’s best selling range of high-performance low-E (low-emissivity) glass. PLANITHERM has been specifically designed to maximise interior comfort and energy-efficiency within the home. PLANITHERM glass has an advanced coating which is designed to reflect the heat from inside the home back into the room, whilst absorbing more warmth from natural daylight.

    • Where can I buy triple glazed windows?

      Triple glazing is relatively new in the UK and is not yet offered by all window installers. The PLANITHERM Installer network is made up of over 800 window installers across the UK, many of whom can offer triple glazed solutions.

      To find PLANITHERM installers near you simply enter your postcode into our search facility.

    • How does triple glazing fit with the current building regulations?

      In terms of thermal insulation, the performance of a triple glazing unit far exceeds the current minimum performance level required by Building Regulations. However, the Building Regulations are anticipated to tighten in the future.The Government has recently introduced the Code for Sustainable Homes, which is the national standard for the sustainable design and construction of new homes. The initiative is designed to move us towards building zero-carbon homes by 2016. The strict energy efficiency requirements of the programme are likely to require triple glazing solutions to be implemented from this point.

    • Will installing triple glazing instead of double glazing mean that overheating will be a problem?

       No. This is a common misconception with triple glazing. The level of solar heat gain from outside is actually less through a triple glazed window than a double glazed window due to the extra pane of glass and cavity present. The overall energy balance of a triple glazed window is superior to double glazing due to its vastly enhanced thermal insulation properties which ensures that more heat is retained within the room instead of being lost through the window.