Traditionally associated with period homes, most people would agree that sash windows add character to a property. But it’s not all about good looks. Naturally, homeowners want their windows to be as practical as they are beautiful.
In an age of rising costs, most people want to install new windows that retain as much heat as possible. But if you own an older home, you may be wondering – can sash windows even be energy efficient?
This brief guide takes a deeper dive into the energy efficiency of sash windows. Included below is a short history of sash windows, as well as what factors can ensure windows lose as little heat as possible.
By the end of this article, you’ll know all you should about whether sash windows can help to keep your fuel bills low. Before we delve into the matter of energy efficiency, here’s an overview of what sash windows are, and their history.
What are Sash Windows?
The key factor that distinguishes sash windows from other types is how they open. Unlike other kinds, a sash window does not open by swinging outwards horizontally or vertically. Rather, a sash window opens by sliding up and down vertically.
Sash windows consist of two sashes that fit inside one main frame. Each of these may comprise a single pane of plain glass or may have decorative bars dividing them into a series of smaller panes. Most sash windows are rectangular, but some may be arched at the top.
A system of concealed pulleys and weights works to ensure sash windows stay open when you want them to. This is cleverly hidden within the frame, giving the windows a seamless look.
The History of Sash Windows
Sash windows are particularly associated with specific eras. They were a key feature of Georgian and Victorian architecture. So, if you own a home from either of these periods, then you may well have sash windows. Architects have used them since then, however, especially to add character and charm to a property.
Originally, sash windows were made from wood. Today, sash windows may be made from modern materials such as UPVC (unplasticised polyvinyl chloride). This is a practical choice as it cannot be penetrated by water. If you want an authentic look, however, then treated timber is the natural alternative.
Some of the oldest sash windows in England can be found locally at Ham House, a National Trust property in Richmond. These date back to the 1670s. The sash windows at Palace House in Newmarket, Suffolk are also said to be a similar age.
Sash Windows and Energy Efficiency
While there’s little doubt that sash windows look good, can they be energy efficient? To find out, let’s cover what makes a window energy efficient, followed by how this can be applied to a sash window.
What makes windows energy efficient?
Any window comprises a number of components, and each of these can affect the window’s overall energy efficiency. The glazing and the frame both play a major part in whether or not a window can retain heat, as do the seals.
It may surprise you to learn that more heat is lost through a window frame than through the glass. Therefore, the material used for the frame can be critical in determining whether or not a window is energy efficient.
The size of the window is also important. In a sense, the bigger a window is, the more energy efficient it will be, as there is a lower ratio of frame to glass. However, the U-Value of a window – a measure of its thermal efficiency – can be misleading.
This is because a higher wall to window ratio within a building equals less heat loss. In essence, then, a smaller sash window will lose less heat overall, as compared to a larger one.
How sash windows can be energy efficient
The choice of materials is critical when it comes to the energy efficiency of any window, as the glazing, the frame, and the seals all play a key part.
Accoya wood is the natural choice for the frames when you want to retain an authentic look yet maximise energy efficiency. This specially treated type of timber is superior to other types of wood when it comes to heat retention, meaning you can save on your fuel bills. Accoya wood is also sustainable and very durable indeed: frames made from it can last for up to 50 years.
Using high performance glass can also ensure minimal heat loss. K Glass, for example, has a special coating that can help reflect heat back into your home, thus reducing your fuel bills.
There are other elements of a window that can improve energy efficiency, too. These include the seals. If these are cleverly designed and carefully fitted, they can help to ensure draught-proof sash windows that retain as much heat as possible.
The application of high-quality spray paint can also help to protect a window frame from the elements, resulting in as little heat lost through it as possible.
All Woodcock sash windows are handmade in our Chertsey workshop, using K Glass and Accoya wood, and featuring advanced draught-proofing. For practical advice, transparent pricing, and the perfect fit for your home, why not get in touch with us today?
