In terms of how much you’ll save, it depends on what type of window you’re replacing. For example, swapping an old-fashioned, single glazed timber frame window for a double glazed aluminium one could cut your fuel bills in half. If you lived in a semi-detached house and upgraded all the windows in this way, that could shave £195 off your energy bills every year. When you consider that your aluminium windows can potentially last up to 45 years, that’s an incredible amount of money.
Alternatively, if you’re replacing a good quality, double glazed uPVC window with an aluminium one, the savings wouldn’t be as drastic. uPVC and aluminium windows typically achieve similar u-values. That being said, if you’re considering replacing a uPVC window, there’s normally a reason for it. Homeowners don’t tend to get rid of windows unless they’re old, damaged, or compromised in some way. If you have uPVC frames and they’re still in good condition, there’s less reason to get an upgrade than if they’re leaking rainwater and letting draughts in.