I'm just looking at some additional borrowing to complete bits and pieces that somehow we overlooked when budgeting for our house makeover (oops!). If we're arranging some more borrowing anyway, there's an argument in favour of borrowing to fit PV solar now rather than wait until we can afford it from ready cash (maybe a four years from now) by which time there will be no FiT. I can borrow easily at 6.2% over 1-5 years (perhaps a better rate if I looked a bit harder) and the estimate for return on the panels for the FiT is 7.7% on the slightly smaller array (1755W using 7 x EGing 195W) and 7.6% on the larger array (1950W using 7 x Solvis 250W and 1 x Solvis 200W).

Long story short, I need an EPC rating of D or better, which I don't think I'll have any difficulty with post insulation, except that I now read (on the Landmark website) they just work out the EPC on the age/construction of the house (i.e. solid walls) and don't accept insulation unless visual or documentary evidence of it. The reclaimed wood beam -> floorboard floor has now been laid, looks beautiful and it's not coming up for any reason - even to show a skeptical EPC assessor (will photos of work in progress on my phone count as visual evidence??). Will the building control approval (presuming I get it on the aerogel - still not heard back) count for the purpose of the EPC? What about the payment papertrail to my builder for work done.

A set of 'Building Regs approved' plans will suffice. If you can produce time/date stamped photos all to the good. The DEA has to cover his/her back, if your EPC gets audited, it is their accreditation on the line....!

The more evidence the better....

Cheers....