As a general rule, rooflights that are being replaced due to damage need only be replaced to the same standard of the damaged rooflight.
Where a series of rooflights are being refurbished to improve their performance and the daylighting within the building, then they should be upgraded to comply with current Building Regulations minimum standards wherever practicable. The requirement should also take into account the cost of the actual work and expected payback period and whole project cost.
Dependent upon the scale of the work, the cost involved and the expected payback period. In many cases, some improvement to the thermal performance can be quite simple, straightforward and cost effective to be of benefit the building anyway.
