Journal
Working notes, mostly about arithmetic
Things we keep having to explain twice, written down once. Method, kit, money, and the occasional account of a week where it rained.
Archive
Everything else
What half a percent a year does over twenty-five
Degradation is the clause every datasheet carries and no quote models. Compounded across a warranty period it removes about a ninth of the output, and it removes it from the years that matter most.
Money
Choosing an inverter you can still buy in 2039
Panels outlive inverters by about a decade. The question is not which inverter is best today, it is which manufacturer will still sell you the replacement, and at what price.
Kit
Scaffolding, slate, and three days of rain
A nine panel install on a listed cottage in Dent, and what an in-roof mount costs in labour when the slate has to come off and go back on by hand.
Site notes
We quote self-consumption before we quote panels
Two houses with identical roofs and identical arrays can have paybacks nine years apart. The variable is not the roof. It is when the kettle goes on.
Method
Next step
Or skip the reading and run the model
Everything argued about here is already priced into the calculator. Change the inputs and watch which of them actually moves the payback.