Underfloor Insulation Question

[Deleted member 63160]

My lounge is 4m x 6 1/2m. 3 walls are internal. The one external wall which is 4m wide is about 2/3 bay window. I've planned to rip the floor up and put 170mm rockwool between the joists but have started to wonder if I'll really notice the benefit due to having over 5m2 of double glazing at one end.
Any thoughts?

 

[Deluks]

Do it. Unless the window is single glazed in which case replace that as the priority.