Solar Basics
What standard test conditions measure, and why a roof never provides them
A panel’s rated wattage is its output at one irradiance, one cell temperature and one atmospheric path, and…
· 4 min read
Arjun Nair
Staff writer, Power Your Roof
Arjun has been reporting on solar basics, batteries, bills & tariffs since long before it was fashionable and thinks most subjects are more interesting once you know how they work.
13 articles
Installation
Every roof penetration is a future leak unless the detail is right
Mounting an array means passing fixings through the weatherproof layer of a building, and the difference…
· 4 min read
Bills & Tariffs
Kilowatts and kilowatt-hours are different products, and some bills charge for both
Confusing a rate with a quantity is the commonest error in household energy, and it hides both in tariff…
· 4 min read
Installation
An ageing roof should be replaced before the array goes on it
Panels outlive most roof coverings, and removing an array to re-cover the roof underneath costs the access…
· 4 min read
Installation
Access and scaffolding drive more of the price than the panels do
Modules are now among the cheaper parts of an installation, so the cost of a job is set largely by how…
· 4 min read
Efficiency
Keeping a house cool is mostly about stopping heat getting in
Once sunlight has passed through glass its energy is inside the building, so external shading beats every…
· 4 min read
Solar Basics
An array is sized against the household, not against the roof
Filling the available area is the default approach and it produces systems whose last few panels earn a…
· 4 min read
Solar Basics
Why an array is often larger than the inverter it feeds
Fitting more panel capacity than the inverter can pass looks like a mistake and is usually deliberate…
· 4 min read
Efficiency
Insulation is several different products solving several different problems
Fibre, rigid board, blown fill and reflective foil behave in quite different ways, and choosing by…
· 4 min read
Batteries
What becomes of a home battery once it stops being useful
A worn storage unit is a heavy assembly of valuable metals inside a casing designed never to be opened, and…
· 3 min read
Batteries
The mode a battery is left in matters more than another kilowatt-hour
Storage hardware is inert without a control strategy, and the default strategy shipped in the box is…
· 3 min read
Installation
What the commissioning measurements are actually testing
A handful of numbers taken on the final afternoon establish that the array was wired as designed and that…
· 4 min read
Efficiency
Cooking uses less energy than the attention it receives
The differences between hobs, ovens and kettles are real and they operate on a share of household energy…
· 4 min read