Aye just had a boiler fitted Jack, had fellers crawling all over it with test meters at the end & I have lots of important looking technical bits of paper now. The new one is 30% more efficient than the old one apparrently, it gets extra heat back out of the exhaust pipe
It's just like some kind of booklet that says how energy efficient a building is. Gives some kind of a rough guide to likely running costs I think. You have to pay some kind of accredited assessor to come round and use some european union approved calculator program, stick allsorts of stuff in like, do you have loft insulation, is the boiler a low fuel consumption one, have you got double glazing etc etc etc etc
It spits out a grade kinda like council tax bands, think it's band A thru band G. one end is the most efficient, the other end the least.
If someone's the sort of landlord that keeps a property in good modern condition as a normal part of their business it shouldn't really worry them as they should more or less get a goodish grade anyway, if otoh they're a skinflint that won't maintain the property properly it would end up putting them in a less efficient band & thus making the property less attractive to potential tenants.
should encourage people to invest in stuff that's good for reducing co2 emissions

if anyone's looking for a job, getting accredited as an assessor might be a handy string to add to the bow.. dunno how much the training costs