Frequently Asked Questions for sash windows
What are sash windows?
A sash window is a window made up of two glazed panels, called sashes, that slide vertically past each other to open. Sometimes one sash is fixed and slides, or usually both sashes slide open. The benefit of sash windows is their ability to provide natural ventilation by opening a gap at the top and bottom of the window that creates a natural draw in the room.
Sash windows were predominantly fitted in Georgian, Victorian and Edwardian period properties in the UK, recognisable by their tall proportions and glazing bars.
Modern sash windows are made in timber or uPVC and come double glazed.
A sash window works with an internal counterbalance that holds them open at any height. Traditional sash windows use a hidden weight inside the box frame, connected to the sash by a cord running over a pulley. Modern sash windows more commonly use a spiral balance, a spring mechanism that does the same job inside a slimmer frame.
Can you get double glazed sash windows?
Yes. Modern sash windows are double glazed.
A modern sash window can hold a full-width double glazed unit. A traditional sash in a conservation area may have a slimline unit to match the original appearance and depth of the sash frame. This allows a more insulated window whilst retaining the character of the original window.
Everest sash windows are double glazed and made to measure in timber or woodgrain uPVC.
Are sash windows energy efficient?
Modern sash windows are energy efficient with double glazed units, weatherproof seals around the edges and have been manufactured for a snug fit to avoid any rattling or draughts.
Everest uPVC sash windows are A-rated for energy efficiency while keeping the traditional appearance.
Are wooden sash windows draughty?
Original period wooden sash windows are beautiful, but single glazed and draughty due to warping and worn seals around where the sashes slide. This resulted in many original sash windows being lost and replaced with uPVC casement windows.
New wooden sash windows are not draughty. Everest timber sash windows are made from engineered, laminated wood that resists twisting and stops rattling, with weatherproof seals and double glazing as standard.
Do you need planning permission to replace sash windows?
In England, you do not usually need planning permission to replace sash windows for a like-for-like replacement of similar appearance.
You will need permission if your home is listed, or if an Article 4 direction applies to your property, which is common in conservation areas and removes any permitted development rights.
Note, building regulations apply separately to window replacement. If you use a window installer registered as a competent supplier, you will not be required to apply for regulations.
Read more about planning permission.
How much do sash windows cost?
For windows manufactured bespoke, a new uPVC sash window can cost between £2,500 and £4,000 per window installed, and wooden sash windows cost around 50% more, between £3,000 and £5,000.
Sash windows cost more than casement windows because they are more complex to manufacture and fit, and involve the removal of the old sash box adds installation time. Ordering several windows at once brings down the cost per window.
Read more about the cost of new windows.
