Vicaya GlobalCalculator · Solar

Solar calculators that show their working

Most solar calculators exist to collect your phone number. These model the actual physics — sun position, atmosphere, the angle light strikes the glass, how hot the panels get — and publish how far they deviate from an independent reference.

• No email address, no postcode capture, no quote form.
• Every assumption is stated on the page it affects.
• The measured error is published, including where the model is worst.
• Every chart has a table equivalent, and everything works from the keyboard.

Built

Live now, and every figure on them comes from the same physics engine.

• Simple solar calculator

  Start here if you have not bought anything yet. Size, generation, savings, cost, payback and carbon from one answer: your bill, your units or your roof area.

• Installation cost calculator

  The inverse of the simple calculator: enter a quote you already have, line by line, and see the all-in total, the cost per watt every quote is compared on, and where the money goes — hardware, labour and soft costs.

• Solar panel output calculator

  What a given array actually generates across a year, from sun geometry and atmospheric physics rather than a datasheet number multiplied by daylight hours.

• Orientation optimizer

  Every tilt and bearing combination at once, as a yield surface, so the cost of the roof you actually have is visible rather than inferred one guess at a time.

• Savings and payback

  What a system returns under real tariff and export terms, with the inverter replacement budgeted and exported energy valued separately from what you use yourself.

• Battery sizing and payback

  Hour-by-hour dispatch across a full year: what a battery actually saves, and why the returns flatten so sharply once it can absorb a typical sunny afternoon.

• Financing compared

  Cash, loan and lease reduced to one measure over one horizon — including who owns the panels at the end, which is the term leases are quietest about.

• Methodology and measured accuracy

  The full physics chain, every assumption, and how far the model deviates from PVGIS for each class of site — including the cases where it performs worst.

Technical

Market-neutral hardware questions. No tariffs, no incentives — physics and arithmetic that hold anywhere.

• Inverter sizing

  What DC:AC ratio is worth buying where you are — because the "1.2" everyone repeats is a sunny-climate rule, and a cloudy site wants a considerably smaller inverter.

• Inverter clipping

  What an inverter smaller than its array actually costs, month by month, and whether a bigger one would ever repay the difference.

• Bifacial gain

  What the rear face collects once you account for what is standing behind it — which on a flush pitched roof is very close to nothing.

• Tracker vs fixed

  Single-axis and dual-axis against a well-aimed fixed frame. The gain is mostly a question of latitude, and at some latitudes it is negative.

• Cleaning and soiling

  Whether cleaning pays for itself: dirt weighted by the generation it actually costs, against what a cleaner charges — and how often rain has already done the job.

• Off-grid sizing

  Array, battery bank and controller sized on the worst month rather than the annual average, which is the mistake that leaves an off-grid site dark in December.

• Shading and horizon

  What a tree, a chimney or a ridgeline actually costs — direction by direction and month by month, rather than as the single annual percentage that hides when the shade falls.

• Peak sun hours

  What the unit means, the figure for your own plane rather than a horizontal table, and the watt, watt-hour and amp-hour conversions built on it.

Next

Specified and validated, not yet built.

Planned

On the roadmap. Listed so the shape of the section is clear, not to imply they exist. Nothing sits here at present: everything specified has been built, and everything unbuilt is unbuilt for a stated reason rather than for want of time.