How Long Does a Solar Panel Install Take?

There are two versions of this question, and people usually mean both at once. How many days will there be scaffolding up and somebody in my loft? And how long from saying yes to actually seeing the benefit on a bill?

The honest answers are 2 to 3 days for the installation itself, and a few weeks either side of that for the parts nobody photographs.

Before anyone turns up

The survey does most of the quiet work. It confirms the roof structure and covering are sound, measures the usable area, logs shading from chimneys, trees and neighbouring buildings, and sets the panel count and layout. A typical home takes 6 to 20 panels at 460W each, and where those panels sit is a design decision, not a case of filling the roof.

The other thing that happens early is the grid side. If the inverter output is 3.68 kW or less per phase, your installer notifies the distribution network operator after commissioning, within 28 days, under G98. Above that, a G99 application goes in beforehand and approval can take several weeks. This is the single biggest reason one job starts a fortnight after survey and another takes two months, so it is worth asking which route your design needs before you plan anything around a date.

Scaffolding is booked separately and usually goes up a day or two before the install, then comes down a few days after. It is also the part most likely to move for weather.

Day one: the roof

Roof anchors go in first, fixed into the rafters and flashed or sealed back into the covering. Mounting rails are levelled across them, then the panels are clamped on and the DC cabling is run into the loft. The array is kept off the roof edges, both for wind loading and because permitted development has rules about how close to the edge equipment can sit.

Most single roof installs get the full array up in a day. Multiple roof faces, an awkward pitch, or a slate roof that wants careful handling can push it into day two.

Day two: the electrics

Inside, the inverter goes on a wall in the loft or garage, with DC isolators either side of it, an AC connection back to the consumer unit, earthing and surge protection. If a battery is part of the system it is positioned and connected at this stage, usually in a garage or utility space, and because batteries are stackable anywhere from 5 kWh to 60 kWh the physical work scales with how many modules there are.

Then the system is commissioned. Strings are tested, the inverter is configured for the local grid settings, generation is checked against what the design predicted, and the monitoring app is set up on your phone so you can see what the roof is doing. You should get a walkthrough of where the isolators are, what to do in a power cut, and how to read the app without worrying about every cloud.

We use subcontractors for some of the work, which is normal in this industry. We manage the job from survey to handover and take responsibility for it either way.

The paperwork that follows

Your MCS certificate has to be issued within 10 working days of commissioning. It matters more than it looks: it is the document energy suppliers rely on, so it is what unlocks the Smart Export Guarantee. Export rates sit around 12p per kWh against grid electricity at roughly 24p, which is why using your own generation is always worth more than selling it, and why a battery changes the numbers.

The SEG application goes to a supplier after that, and needs a smart meter capable of half hourly export readings. Payments start from the next billing cycle, so allow a few weeks before anything shows up.

So what is the realistic total?

For a straightforward G98 job: survey, then a couple of weeks for design, materials and scaffolding, then 2 to 3 days on site, then two to six weeks before export payments are flowing. A G99 design adds the approval wait at the front.

The panels generate from the moment they are commissioned. Everything after that is admin, and it is ours to chase, not yours.

If you want a proper timeline for your own roof, including which grid route it falls under, our survey is free and there is no obligation.