Windows have a major impact on energy efficiency in the home. A square meter of glass in direct sun can allow as much heat in as a small single bar radiator. Heat loss from a window can be ten times the loss through the same area of insulated wall. There are a number of retrofit options available. They can be implemented on any budget and any level of skill. Read on...
Retrofit double glazing could reduce heat loss from windows from 50% or even 70% with more expensive approaches. For a 10m2 area of glazing this could equate to a saving of around 7kWh per day – around 25% of the average energy bill! The following image shows how you can calculate the heat loss "U value" of a window.
Retrofit double glazing could improve a windows thermal performance by over 50%. This will depend on the type of approach and how well it is implemented.
There are many approaches to retrofitting doubble glazing. Each with its pro's and cons. The following table outlines these.