You may want to consider triple glazing, although the money you could save on your energy are not great compared to how much they can cost to install.
For existing properties, high quality windows are essential to maintaining good energy efficiency. Good quality windows can last years so it's important to pick the right ones.
Your windows should have a minimum of double glazing and should be air-tight to stop any air leaking through. This should help reduce your energy bills as less warm can escape.
New windows should be positioned on a bed of mortar with the rear of the frame in the same location as the existing windows, reducing the amount of disruption required within the dwelling. Once positioned, fix through the frame into the brickwork ensuring packers are placed between the frame and the wall at the fixing locations to offer maximum support.
Any remaining gaps between the frame and wall should be filled with expanding foam to give support and to form an insulating barrier. Once the foam has set and been cut flush with the frame face, sealant should be applied around the whole window frame. To finish internally either fix painted softwood or uPVC cover strips/quadrant.
When replacing windows make sure there are no planning or heritage constraints placed on the dwelling.
When measuring up for replacement windows be careful to ensure each window will fit as new windows come square and true but old openings may not be.
If there are large gaps around the frame on the outside it may be better to either use a mortar fillet or install painted softwood of uPVC cover strips/quadrant.
All properties lose heat through their windows. But energy-efficient glazing keeps your home warmer and quieter as well as reducing your energy bills. That might mean double or triple-glazing, secondary glazing, or just heavier curtains.
Some window manufacturers show the energy efficiency of their products using an energy-rating scale from A to G. The whole window (the frame and the glass) is assessed on its efficiency at retaining heat. The scheme is run by the British Fenestration Rating Council (BFRC).