My Crittall windows are cold, what are my options?
Posted by Helena Ripley on 4 September 2015 at 3:20 pm
Crittall is a company which produces steel framed windows and their name has become associated with metal windows in general, which are now produced by many other companies. First manufactured back in 1884, when someone says Crittall windows we know exactly what they mean. Steel and aluminium produce strong, long lasting window frames which made them a popular alternative to wooden frames. From their earliest days made of steel, through the 1930s heyday to the 1950s aluminium alternatives, these windows have always looked good. However, there are issues with older metal window frames as they are poor insulators and can rust and warp.
What is best to replace them with?
Many people would suggest that uPVC is the way to go as it is the most efficient. These frames are also the cheapest option but they do need replacing more often than other alternatives. Wooden frames are also cheaper and better insulating than metal ones but come with their own issues – they expand and contract with changes in the weather. You may not consider these to be a viable alternative as you would lose that historical Crittall look.
I live in a conservation area, what are my options?
You might face some restrictions when replacing your windows; check with your local authority to see what is allowed. You can get replacement windows made in steel or aluminium but they can be costly. Genuine bespoke Crittall windows can cost around £3,000 each. Aluminium is a cheaper alternative to steel and can be made to look similar to your original Crittall windows. The most important thing is that the windows look the same from the street.
New Crittall windows are specifically treated to prevent the frames warping or rusting. So, if you need new metal windows they should provide more comfort than the old ones. In fact, many architects are now deliberately designing with Crittall windows as they look so good and meet building regulations for efficiency.
What do I need in my new windows?
Whatever frame you go for there are some steps you can take to make sure that your windows are as energy efficient as possible. Firstly, go for double glazing if possible. This can be enhanced if the gap between the panes is filled with inert gas (argon or krypton) to further reduce heat loss. You could also go for a low emissivity (low-e) window; these allow selected parts of the electromagnetic spectrum through the window. Visible light is obviously necessary but low-e windows block damaging ultra violet rays and help to trap infra-red radiation (heat) in the room. A double glazed low-e window can have the same energy efficiency rating as a triple glazed window.
Windows, particularly the frames, can act as thermal bridges. This is where heat can easily escape from your home and condensation can form, you will be very aware of this as an issue with your old existing Crittall windows. To minimise this effect thermal breaks or warm edge spacers are needed; these insulate the glass from metal in the frame. Also newer frames are dipped in a polyester coating to avoid thermal bridging (and it removes the need for repainting).
The best way to find the most energy efficient window is to look for the U-value of the whole window, including the frame. The lower the U-value the better insulated the window is. See our previous blog on windows.
I don’t want to replace my windows, what else could I do?
If you don’t want or need to go to the expense of replacing your windows but do want to make your home more energy efficient there are several options. The simplest thing is to close your curtains and blinds when it starts to gets dark; this way you can get the most warmth from the sun and limit the loss of heat. To maximise this effect you could invest in thermal blinds, curtains or shutters.
Secondary glazing is another option, this is fitted on the inside of your windows. There is little visual impact from outside and unlike curtains you can use secondary glazing throughout the day. Though do note that some local authorities won’t even allow secondary glazing in listed buildings or conservation areas. Some people have found that removable secondary glazing is the way to go. It is put firmly in place during the winter when energy efficiency is most valued and then removed in spring when windows are more likely to be left open and fresh air is welcomed.
Remember it is always a compromise; the most efficient window will not be a like for like replacement for your Crittall ones. So you have to decide what your priority is and what your local authority will let you do.
Photo credit: Crittall Windows
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