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.

Upgrading window glass


We can replace the existing glass and upgrade the glazing of heritage windows when combined with our Draught Seal & Restore service.  

Energy Efficient Low-E single-glazing is available that can be retro-fitted into your existing sashes.  Thicker glass equals more weight and so the window weights must also be increased.

Low-E laminated glass makes your home warmer, quieter and more secure. Regardless of the temperature outside a window with good insulation properties will help to improve the comfort of your home.

Replace Glass with Standard Laminate

Laminated Glass is manufactured by bonding multiple panes of glass together with a thin, single layer film sandwiched between the glass layers. Laminated glass has many benefits including greatly reduced ultra violet (UV) light ingress. to protect your interior furnishings from fading; Grade A safety rating; Greatly improved security and noise reduction of up to 24% over existing 3mm float glazing .

Glazing upgrade with “Hush” glass

Acoustic Insulating Glass provides all the benefits of standard laminate plus a special 3-layer acoustic PVB laminate interlayer that is specifically designed to reduce sound transmission. Reductions of up to 40% in comparison to similar thickness float glass may be achieved.

Glazing Upgrades For Timber Windows 2

Upgrade glazing with “Comfort” glass

A Factory applied  low e coating to one of the glass surfaces improves 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.

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 obviously some sash frame alterations are required.  Deepening the glass rebate to install double glazing is only possible with sashes 42mm or thicker as otherwise the mortise and tenon joints will be considerably weakened. 

With the advances in single glazing, laminated glass is often the best solution. 

Pilkington Spacia™ is a recent innovation which provides similar energy efficiency performance as a standard 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. 


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.
  • Air borne 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 frequently need to be replaced, at additional cost.  Our standard replacement sash cords are more than sufficient to carry the additional weight.

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.