Choosing windows means considering details beyond the glass. The way a window opens impacts ventilation, how secure it is, appearance, and ease of cleaning. Two of the most common window styles in the UK are casement and sash windows, and each style has its pros and cons for different homes and occupants.
What are casement windows?
Casement windows are hinged on the side and open outward like small doors. They are the most common style of window in modern houses. Because the sash closes against the frame by means of a compression seal, a good fit on a casement window can provide an effective seal against draughts and even rain. Casement windows have the best possible clear, unobstructed opening of all types of windows, and are excellent for allowing the passage of fresh air when needed.
Casements come in many different layouts. A standard configuration would be a series of large, fixed lights, with an operable casement adjacent to it. Some casements come equipped with a top-hung opener for nighttime ventilation. Security is rarely an issue, as quality casement windows come standard with handles and multi-point locking systems.
What are sash windows?
Sash windows slide vertically within their frame. Traditionally, a counter-weight system was used to balance the windows. Spring balances are now used which provide a quieter, easier to maintain system. A period property can lose its character if modern windows are installed. Sashes are traditionally associated with Victorian and Georgian houses, so to retain the character of a property, sash windows are often the only alternative.
Ventilation control is important. With sash windows you can open the top sash to let the hot air escape and open the bottom to let the cooler air in. Another benefit is that they don’t project outwards like other windows which can be more convenient for streets where a window swinging out would be in the way of other people.
Comparing the two
Appearance: Sash windows have a classic look, with slim glazing bars. Casements can suit both traditional and modern styles. If your house is in a conservation area, check for any local requirements. Some councils will expect you to match the style of the front of the house like-for-like.
Energy efficiency: Both can achieve superb thermal performances with double or triple glazing, warm edge spacers and other advanced glazing techniques. Casements tend to be a little bit more airtight due to compression seals, but modern well-made sashes with brush seals also perform very well.
Security: Multi-point locks and sash locks and restrictors can both attain recognised security standards when used in casements and sashes respectively. Look for products that have been tested to the relevant standards, rather than assuming style reflects security in these products.
Cost: Casements are generally less expensive. Sash windows made to match period details tend to be more expensive, but many homeowners consider that worthwhile due to appearance.
Which should you choose?
If you’re lucky enough to own a period home, sash windows may well be the right choice for you, as they preserve the character of the building. On the other hand, casement windows are simple to operate and offer better draught protection than sash windows. They also open wider and have a lower purchase price. Many homeowners end up with a mix of the two, with sash windows at the front and casement windows at the back.
You’ll want to request a specification for every quote. This should include the glass, the frame material, the seals, and the locks. Based on the specification, you’ll be able to compare quotes and make sure you get the right windows for your home.