Hi, work on my new home has started. This is a 6 star home.
The contract has the energy values for windows (U and SHGC). These are on the plans as well as on the energy report produced by the modelling software.
The specifications say windows with 'Low E glass or equivalent within energy values for the windows'. I understand any window that meets the energy rating can be used under the energy rating arrangements.
The builder has advised he is using double glazing, which is more expensive than Low E glass.
Can the builder seek extra costs for this? I would think if the builder - not me - is choosing to use a more expensive type (double glazing rather than Low E) than that is his cost? If I agree he can use double glazing can he later seek this as a variation? Low e windows are available from the same window supplier.
Any advice?