Glossary
Solar has a vocabulary, and finance has another one, and the calculator borrows from both without stopping to explain either. This page explains the lot in plain English, in alphabetical order, along with the handful of words that mean something specific inside Solar Desk.
Activation
Section titled “Activation”The moment Solar Desk switches an installer’s account from pending to live, which is when their calculator starts answering the public instead of returning a 404. It happens after a three-item check: real pricing entered, at least one panel in the catalogue, and an address for new enquiries to be sent to.
Amount of credit
Section titled “Amount of credit”On a monthly plan, the part of the price you are actually borrowing: the total cost less your deposit. Interest is charged on this figure rather than on the full price, which is why a larger deposit brings down the cost of credit as well as the monthly payment.
Annual Percentage Rate: the yearly cost of borrowing, as a percentage. Solar Desk treats it as an effective annual rate, so the monthly instalment is not the APR divided by twelve but the twelfth root of one plus the APR, which is why the payment can sit a penny or two away from a rough calculation. Longer terms usually carry an APR, 7.9% over 120 months by default, and shorter ones are often offered at 0%.
Battery storage
Section titled “Battery storage”A battery that holds the electricity your panels generate in the daytime so you can use it in the evening instead of buying it. It raises your self-consumption, which raises the yearly saving, and it adds to the installation cost. Ticking the battery box on step 4 shows you both effects at once.
Confirmed value
Section titled “Confirmed value”On the installer dashboard, the total value of the quotes sitting at the Bought status: work actually won. It sits beside pipeline value, which counts everything still in play.
Cost of credit
Section titled “Cost of credit”What spreading the payments costs you: everything you pay in total, less the amount you borrowed. On a 0% term it is nothing. It appears twice on an estimate, once among the four instalment figures and once in the representative example.
Deposit
Section titled “Deposit”Money you pay up front, so you do not borrow it. In the calculator it is a slider from nothing up to a cap the installer sets, 25% of the price by default, and raising it brings down the monthly instalment, the amount of credit and the cost of credit together. An installer can also put a deposit figure on a quote directly.
DNO application
Section titled “DNO application”The DNO, or Distribution Network Operator, is the company that owns the electricity network in your area, which is not the same company as the one that sells you your electricity. A solar installation has to be registered with them, and your installer handles that as part of the job. It is named in the standard quote line describing the system, and installers usually cover it in their base installation cost.
Economy 7 and two-rate tariffs
Section titled “Economy 7 and two-rate tariffs”Tariffs that charge one price for daytime electricity and a different, cheaper one overnight. If you are on one, put both rates into step 3 rather than averaging them yourself: solar displaces daytime units specifically, so the gap between the two rates changes the savings figure noticeably.
EV tariff
Section titled “EV tariff”An electricity tariff aimed at electric-vehicle owners, normally with a very cheap overnight charging window and a higher rate the rest of the time. The same advice applies as for Economy 7: give both rates. A household charging a car is also a good candidate for the High band on step 3.
Export tariff
Section titled “Export tariff”What your electricity supplier pays you for solar you generate but do not use, in pence per kWh. It is normally well below what you pay to buy a unit, and that gap is the reason using your own generation at home is worth more than exporting it. Your installer sets the export rate their estimates assume, on their Pricing page.
Installer account (tenant)
Section titled “Installer account (tenant)”One installer’s own space in Solar Desk: their pricing, their catalogue, their branding, their web address, their staff and their leads. Nothing crosses between accounts. “Tenant” is the internal word for the same thing, which is why you will see phrases like “a tenant address”, meaning a calculator address belonging to one particular installer.
Inverter
Section titled “Inverter”The unit that converts the direct current your panels produce into the alternating current your house and the grid run on. Every system has one, and it is named in the standard quote line alongside mounting and scaffolding. Installers keep the ones they fit in their product catalogue.
Kilowatt hour, the unit electricity is measured and billed in. Your annual statement gives your yearly use in kWh, and that is the most accurate answer you can give on step 3. Generation uses the same unit: a UK system produces roughly 850 to 950 kWh a year for every kWp installed.
Kilowatt peak, the size of a solar system: what it would produce under standard test conditions, not what it makes on a wet Tuesday in Manchester. It is the panel wattage multiplied by the number of panels, divided by 1,000, so twelve 440 W panels make a 5.28 kWp system. Everything else, generation, saving and payback, is worked out from it.
One homeowner enquiry: the answers they gave, the estimate they were shown, and everything that has happened since, including status, notes, messages, documents and quotes. The dashboard calls the list of them quote management, so the same row gets called a lead and a quote depending on who is talking.
The Microgeneration Certification Scheme, the UK scheme that certifies small-scale renewable products and the companies that install them. Supplier and grant schemes commonly ask for a certificated installation, so it is a fair question to put to an installer early. Solar Desk holds no certification details, so ask them directly what they are certificated for.
Orientation
Section titled “Orientation”Which way the roof face carrying the panels points. South catches the most sun in the UK, with east and west noticeably less, so it moves the generation figure. Step 2 lets you answer “not sure”, and that stays genuinely unknown: the estimate assumes south and tells you on the page that it has.
Panel wattage
Section titled “Panel wattage”How much one panel produces at peak, in watts. Multiply it by the number of panels for the system size in kWp. Installers set the wattage they usually fit on their Pricing page, and every panel in their catalogue carries its own, shown next to the name when you pick one on step 4.
Payback period
Section titled “Payback period”How many years of savings it takes to cover the installation cost. Solar Desk works it out simply, cost divided by yearly saving, with no discounting and on the assumption that today’s tariffs hold, so read it as a marker rather than a forecast. Where the saving would never cover the cost, it shows a dash instead of a number.
Pending
Section titled “Pending”The state of an installer’s account between signing up and being taken live. The dashboard works fully, so pricing, products and branding can all be set up, but the public calculator returns a 404. It is what stops a homeowner being quoted on figures that are still Solar Desk’s placeholders.
Pipeline value
Section titled “Pipeline value”On the dashboard, the total value of every quote still open: all statuses except Bought and Lost. It measures work in play rather than work won, and it moves the moment a status changes.
The slope of a roof. Step 2 asks whether yours is pitched, the usual sloping house roof, or flat, where the panels sit on frames to angle them at the sun. The two are built differently, which is why the question comes before anything is priced.
A priced, itemised document an installer builds for one lead and sends as a branded PDF. It is a different thing from the instant estimate: the estimate is what the calculator worked out from a homeowner’s own answers, and the quote is what the installer will stand behind. Only quotes that have actually been sent are visible to the homeowner.
Quote version
Section titled “Quote version”Every save of a quote is numbered, v1, v2 and so on, and amending writes a new version rather than editing the old one. The reason is that the customer already has the previous version in their inbox, and a document that quietly changes after it is sent is worse than a second document. Homeowners see every version that was sent, with superseded ones marked as such.
Representative example
Section titled “Representative example”The standard block of finance figures shown beside an instalment plan: the price of the goods and installation, the representative APR, the deposit, the cost of credit, the amount of credit, the term, the total amount payable and the lender. It cannot be switched off while finance is on. It is an illustration rather than an offer of credit, and the rate you are offered depends on checks.
Scaffolding
Section titled “Scaffolding”Access equipment for working on the roof, and a real cost in its own right on most installations. Installers set their scaffolding figure on the Pricing page, and it is named in the quote line that describes the system, so it is not something that should turn up later as an extra.
Self-consumption
Section titled “Self-consumption”The share of what your panels generate that you use in the house instead of sending to the grid. It is the largest single lever on your saving, because a unit you use saves you the full price you would have paid for it while a unit you export earns only the export rate. A battery raises it, which is exactly why the saving jumps when you tick the battery box.
Shading
Section titled “Shading”Anything that puts your roof in shadow for part of the day: trees, a chimney, a taller building next door. It reduces what the panels generate, so step 2 asks for it as a band, from nothing to a lot, rather than pretending to measure it. An installer confirms it properly at survey.
Smart meter
Section titled “Smart meter”A meter that records your electricity use and sends the readings to your supplier automatically. Export payments generally depend on having one, because something has to measure what you send back. Step 3 asks whether you already have one so that your installer knows what still needs arranging.