Originally Posted by pwurple
Ah it's a bit of mumbo jumbo isn't it really though?
We got our house from an E to a C1 by replacing windows and boiler.
We got it from a C to a B by taking out the lightbulbs.
Yeah, that's true... Its is a box ticking excercise rather than an actual tested efficency report,
But changing windows and replacing the boiler are fairly big expense, and (probably) big result items, attic insulation, led lights and say a lagging jacket are fairly low cost, reasonably easy items, that can still have a big result...And are well worth while.
You might go for solar hot water, or photovoltaic, which could get you an another boost but not really get a return on investment...
In general airtightness (and then controllable ventilation), and insulation (and controllable heating) are gonna get you a return, improve your rating and most important, make your house more comfortable.