Victorian to 1930s
Secondary Glazing for Bay Window Homes
Bay Window Homes stock across South Yorkshire dates from the Victorian to 1930s — 3- or 5-facet bays with leaded lights that were never designed for modern noise or thermal targets. A bay window is the single biggest heat-loss surface in most Victorian and Edwardian houses — and the hardest surface to fix without demolishing the frontage.
Recent installs nearby
Nether Edge Grade II sash retrofit
Six original box sashes fitted with balanced vertical secondary sliders — full listed-building consent secured in six weeks.
Ecclesall Road bay-window sound retrofit
Three-panel horizontal sliders across a 3.2 m Edwardian bay — Rw measured at 47 dB post-install.
Kelham Island loft conversion
Four large steel-frame factory openings sealed with slim satin-anodised horizontal sliders. Post-install U-value 1.87 W/m²K.
Why bay window homes owners choose secondary glazing
For homes with radiators under the bay we specify low-profile heads so the airflow isn't blocked.
A multi-panel horizontal slider follows the bay geometry — templated to each facet so nothing looks bodged.
Adding a thermal-break at the sill closes the last cold-air path into the seating area.
Recommended: Thermal Insulation
cut heat loss through the window by up to 65%
U-values from 1.868 W/m²K
A properly sealed secondary glazing unit with Low-E soft-coat glass reaches U-values as low as 1.868 W/m²K — comfortably meeting current retrofit building-regs requirements.
Common questions
How does this compare to replacement double glazing?
A modern secondary unit with Low-E glass and a 100 mm cavity outperforms most existing sealed double-glazed units — and it works on windows you legally can't replace.
Can Low-E glass be combined with acoustic laminated?
Yes — most heavy specifications combine both, so you get acoustic gain and thermal gain in the same install.
Will it help with condensation on my sash windows?
Almost always — the room-side pane raises the surface temperature of the glass you touch, which stops warm interior air condensing.
What U-value can secondary glazing achieve?
As low as 1.868 W/m²K with Low-E soft-coat glass and a 100 mm cavity — comfortably meeting current retrofit building-regs targets.
How is the quote calculated?
We survey and template every opening on site, then quote in writing per opening — no per-square-metre pricing that hides oversize charges.
Local reference points
- Era
- Victorian to 1930s
- Typical window
- 3- or 5-facet bays with leaded lights
- Top problem
- cold downdraught across the whole bay recess
- Recommended service
- Thermal Insulation
- Recommended product
- horizontal sliders
- Performance
- U-values from 1.868 W/m²K
Next step for bay window homes owners
Send us photos of one or two windows and we'll come back with a written quote and a spec sheet you can compare against replacement double glazing.
Book an on-site survey
We measure and template every opening — no per-square-metre guesswork.