Replacing old double glazing: new units or whole windows?

Single misted unit, frame in good condition: replace the sealed unit only. £150–£300 fitted.

Multiple misted units, frames intact: replace the units, keep the frames. £900–£1,500 for a typical whole house.

Frames warped, rotten, or pulling from brickwork: full replacement is the only sensible option. £4,500–£8,000 for a typical 3-bed Leicester semi.

Two-fitter crew arrives 8am. Dust sheets down, furniture moved away from walls.

Each window: old window out, brickwork cleaned, new window in, packed and shimmed level, sealed with expanding foam internally and silicone externally, trims fitted, made good.

Average pace: 4–6 windows per day for a competent crew. A typical 3-bed house takes 1.5–2 days.

We leave the property weathertight at the end of every day — no half-fitted windows overnight.

All replacement windows in England must comply with Document L (energy efficiency) and Document Q (security on new builds). Your installer must be FENSA or Certass registered and will provide a certificate.

We're FENSA registered and the certificate is lodged automatically — you'll receive it by post within 4–6 weeks.

Skipping the survey. Online quotes that haven't measured your openings always come back with extras on the day.

Cheap trickle vents or no trickle vents. Current Building Regs require background ventilation; cheap fitters skip this and the windows fail the certification.

Not specifying the cylinder grade on glazed doors. Default cylinders are 1-star.

Paying in full upfront. 25–50% deposit is normal; final payment on satisfactory completion is the standard.

Replacement windows are usually the better choice when you see:

Frames that are discoloured, cracked or flexing

Hinges and gearboxes that repeatedly fail

Draughts around the sash even when locked

Several misted units across the house

We survey and measure each opening, the windows are made to size, then each old window is removed and the new one fitted and sealed room by room. A typical three-bed house takes two to three days on site. We cover Leicester and a 30-mile radius, with a 10-year insurance-backed guarantee on the installation.