Glazing upgrades for heritage windows

Upgrade Window Glass

Energy efficient laminated glass or acoustic glass can be retro fitted into your existing period windows.

Upgrade Glass in period windows & doors. Laminated

Single Glazed Sash Windows with good insulation properties.

Regardless of the temperature outside a window with good insulation properties will help to improve the comfort of your home.

Upgrading window glass

We can replace your existing glass to upgrade the glazing in your heritage windows.  Modern production glass can improve safety, security, soundproofing and insulating properties.

Typically domestic heritage windows have 2 – 3 mm window glass.  It is usually possible to double the thickness of your single glazing without significant modification to the frame – existing 3mm glass can be replaced with up to 6.5mm.  The replacement glass will be thicker and heavier, so the sash window weights must also be increased or the windows will not stay in place when opened.  Glazing upgrades are always combined with our Draught Seal & Restore service, as we already have the window dismantled.

Replace Glass with Standard Laminate

Laminated Glass is manufactured by bonding two panes of glass together.  Sandwiched between the panes is a thin, inter-layer of clear film. 

Laminated glass has many benefits including greatly reduced ultraviolet (UV) light ingress, to protect your interior furnishings from fading; Grade A safety rating; Greatly improved security; noise reduction of up to 24% over existing 3mm float glazing.  Great value for money upgrade.

Glazing upgrade with “Hush” Acoustic glass

Acoustic Insulating Glass provides all the benefits of standard laminate, plus soundproofing.  A special acoustic 3ply PVB inter-layer is used that is specifically designed to reduce sound transmission. Reductions of up to 40% in comparison to similar thickness float glass may be achieved.  More information on soundproofing.

Glazing Upgrades For Timber Windows 2

Upgrade glazing with “Comfort” glass

A Factory-applied Low-E coating is baked into one of the glass surfaces to improve energy efficiency. This Low-E coating reflects heat, helping to keep your home cooler in summer and warmer in winter. Up to 39% better thermal insulation than ordinary window glass.

How Does Low-Emissivity Glass Work?

low e glass for period casement and sash windows

Low-e glass has a special coating that reflects heat back into the room.  In winter heat is reflected back indoors, in the summer heat from the
sun is reflected away keeping the room cooler. 

Because a Low-E coating reflects some wavelengths of the light spectrum it will slightly alter the colour tone of the light passing through the glass.  There are various Low-E coatings offered by different glass manufacturers that each have their own colour signature and performance characteristics.  Ask your local branch representative about the options on offer in your area.  



Upgrade glazing with “Comfort” + “Hush”

Hush glass with a Low-E coating results in a quieter more comfortable home with energy savings.

Retrofit double glazing into sash frames?

In some instances, it is possible to install double glazed units into existing timber sash frames.  The thickness and condition of your existing sashes are the deciding factors.  As your original window glass is only 2-4 mm thick and a double glazed unit is 14+mm thick some sash frame alterations will be required.  Deepening the glass rebate to install double glazing is only possible with sashes 40mm or thicker, as otherwise the mortise and tenon joints will be considerably weakened. 

With the latest advances in single glazing, laminated low-E glass is often the better solution. 

Pilkington Spacia™ is a recent innovation which provides similar energy efficiency performance as a standard double glazed unit, but in a much thinner profile. Instead of being gas-filled, a vacuum separates the panes.  These sealed glazing units are only 6.5 mm thick, but currently they remain an expensive option. 

Patterned Glass

Decorative and obscuring glasses are available in a range of designs including acid-etched patterns.

Upgraded glazing benefits include:

Glazing upgrades in a double hung sash window | sash Window Specialist Midlands UK

  • An energy-efficient home is a comfortable home
  • Low E glazing reduces your homes carbon footprint.
  • Reduced UV prevents furnishings from fading
  • Reduced condensation on glass
  • Low friction draught-proofing strips aid smooth window operation and stop annoying rattles.
  • Airborne noise, dust and other pollutants that are suspended within draughts are also greatly reduced.

Our Glazing Upgrades Include:

Sash Weather & Draft Seals.

  • Draughtseal & Overhaul Service
  • Removal of existing glazing
  • Cleaning and preparing rebates
  • Installation of new glass
  • Traditional putty pointing
  • Balancing the weight system with lead.

Counterbalancing Heavier Glazing

Sash Window Lead Counterbalance Weights

An important consideration is that the additional weight will be carried by the pulley.  Whilst the majority of pulleys in British sash windows are sturdy axle pulleys, occasionally some may require replacing.  Many Australian sash windows have cheaper pulleys that more frequently need to be replaced, at additional cost.  Our standard replacement sash cords are more than sufficient to carry the additional weight.

Historic Glass

Before choosing this service some consideration should be given to the benefits of your existing glazing.  Originaly heritage window glass was hand made, resulting in an uneven surface with flaws and distortions.  Historic glass adds to the character of a heritage window in a way that modern float glass can not match.

Read more in our article on window glass

Can you fit a pet door into a heritage window?

Yes, we can fit cat flaps into replacement sash window glass.  Dog doors can be fitted into period doors and french windows.