Get in touch

Fill in the form and let us know what service you are interested in, and we will call you back.

    Ultra slim, energy efficient, vacuum glazing. Perfect for listed buildings and conservation properties.

    If you own a listed building you will understand the importance of preserving the character of your building as much as possible.  Planning officers share the same philosophy, which means that historically, planning permission requests for replacement windows and doors with double-glazing have mainly been declined.

    A modern solution to historical problems
    As approved installers of a new type of glass technology called Fineo, we are now able to offer listed homeowners a comprehensive re-glaze, draft seal and paint service which ensures the original aesthetic of their home are maintained in line with local authority guidelines – without the need for planning approval

    Why is Fineo suited to listed buildings?

    Fineo’s ultra-thin (6.7mm) profile means it can be easily retrofitted into all timber windows and doors– so the original historical frames are maintained.  Because we are replacing the glass within the existing timber frames, you will save months of precious time and thousands of pounds by preventing the need to go through the lengthy application process. 

    Turn your glass into radiators

    Compared to single glazing, Fineo provides substantial improvements to energy efficiency.  A double- glazed vacuum insulated Fineo glass unit boasts thermal efficiencies better than a traditional 36mm triple glazed unit but is no thicker than single glazing.

    Width of single glazing | warmth of triple glazing

    Fineo will keep heat in and cold out no matter what the temperature is outside.  For example, the table below shows that if the temperature outside is -10°C and the temperature inside your home is 20°C, then your old single-glazed windows will only retain -2.75°C opposed to the 17.3°C retained by Fineo glass.

    Compare Fineo with traditional glazing

    • With Fineo’s ultra-thin (6.7mm) profile, in most instances, there is no need to widen the groove in the window frame, so the original historic appearance is maintained.
    • Boasts exceptional thermal efficiencies that are 8 times more efficient than single glazing and 5% more efficient than a 36mm triple-glazed unit.
    • Compared to single glazing, Fineo provides a 34% reduction in perceived traffic noise levels and 18% better than double or triple glazing.
    • Better light transmission. The higher the light transmission, the more light that comes into your property.  Double and triple glazing have lower light transmission values than single glazing, because some of the light is absorbed or reflected by the glass.  Fineo lets more light into your property than both double and triple glazing.
    • Better solar gain. Heat from the sun warms your home, but the type of glass in your windows and doors can affect this. The more glass you have, the less warmth in your property coming from the sun. Fineo allows the sun to heat your property more than triple glazing and almost as much as double glazing.
    • Unlike previous vacuum glazing technologies, Fineo has no evacuation port to obstruct the view and has very thin edge seals ensuring maximum vision area.
    • 50% lighter than triple glazing.
    • Fineo comes with a 15-year guarantee
    • No planning permission is needed – saving you weeks of time and thousands of pounds by preventing the need to go through the lengthy application process.

    A step towards fighting climate change

    Reduces your carbon footprint
    Historically, double-glazing requests submitted by listed property owners have been denied by local councils which has deemed listed buildings to be incredibly inefficient in terms of insulation.  Many period properties will house old heating systems which, when coupled with inefficient glazing, results in masses of wasted energy.  Fineo’s revolutionary double-glazed, energy efficient units will keep older properties warmer and quieter plus, they are lead free and 100% recyclable.

    Zero inert gases
    Fineo is vacuum sealed glazing, which means that unlike traditional double-glazing (that has a gas filled space in between two sheets of glass), all the air between the glass sheets is completely removed.  The vacuum that is created means it is almost impossible for heat to transfer through it which is what makes it so energy efficient.  It also means that unlike double-glazing that needs a noble gas inside of it (which has to be mined, extracted, bottled up, and shipped all over the world), Fineo is an extremely low carbon product to manufacture.

    How is Fineo retrofitted into existing windows/sashes?

    Retrofit into existing window/sashes:

    1. Remove existing single glazing
    2. Retrofit new Fineo glazing into existing sashes
    3. Change cords and re-balance weights of existing sashes
    4. Draft proof the existing sashes
    5. Replace existing ironmongery with new brass lifters, pulleys and rings
    6. New AGC Fineo vacuum double glazing has a U-Value of 0.7 compared to old single glazing 5.8

    Our Fineo re-glaze, draft seal and paint service

    Wandsworth Sash Windows have been draught proofing traditional timber windows in London and the South East since 2012.  We have experience working on a range of listed buildings and period properties.  For customers retrofitting Fineointo their existing timber frames we will also carry out a draft seal and paint service where we will:

    • Draught seal all the windows to help eliminate cold draughts, dust, dirt and noise and to keep the heat in.
    • Where necessary, remove any rot and use a specialist RepairCare system to ensure the longevity of your windows.
    • repaint timber frames to refresh their appearance and looking their best.
    • Fit new locks, lifts, handles and any other ironmongery you may like

    Easily retrofitted into existing timber window frames, ultra-thin Fineo affords period homes the opportunity to enjoy modern warmth and comfort, without impacting their outward appearance.

    Contact the Wandsworth Sash Windows team for more information

    We can help with your bespoke window, door and joinery requirements.  You are very welcome to pop into our showroom, which is based at Unit 2, Kangley Business Centre, Kangley Bridge Road, London SE26 5AQ. You can call us on  02079247303 or email