Long read
Why our first system was the wrong shape, and what we would do now
A 2.8 kWp system was the sensible number in 2019. It is not now, and the reasons are not just about price.
Section · Solar
Panels are mostly a commodity now. What matters is everything around them: inverter choice, roof geometry, the tariff you are on, and the surprisingly large gap between modelled and measured output.
In this section
Updated as we learn more, sometimes against the grain of the industry.
Panels
A short tour of the panel-spec acronyms and which of them you should actually weight in a buying decision.
Inverters
Once you draw the roof out, the right answer is usually obvious. This guide draws it for you.
Install
Three pages on the dullest part of your install, because it is the part most likely to catch fire.
Output
A reader sent us their first year of generation data. We graphed it against the estimate. The story is interesting.
Behaviour
Timers, dishwashers, hot water, EV charging. The four interventions that move the needle.
Show your working
Long read
A 2.8 kWp system was the sensible number in 2019. It is not now, and the reasons are not just about price.
Field note
Where the prices diverge and what each is implicitly betting on.
Reader letter
A reader sent in their generation data and bills. The numbers are not what the salesman promised.