Solar panels for a garage

Garages are quietly expensive. Nobody heats them, nobody lights them much, and yet there is usually a freezer humming in the corner and a gym that runs a fan heater every February. Here is what a plug-in kit can and cannot do about it.

The garage freezer

The chest freezer is the classic garage load: on permanently, ignored completely, and responsible for a surprising share of the bill. Expect 200–400kWh a year for a typical unit, more if it is over a decade old. Because it runs around the clock, a good slice of its consumption falls in daylight hours, which is exactly when a plug-in device is producing.

One caution worth passing on: many appliances are not rated for very low ambient temperatures, and a standard freezer in an unheated garage can behave oddly in a cold snap. Check the manufacturer's minimum ambient rating before assuming an indoor unit will cope outside.

Home gyms

A garage gym adds a mixed bag of loads. Lighting is the constant — often 100W or more if you have done it properly with LED panels. A treadmill draws 600–1,500W while running, a fan 30–80W, a sound system another 30–100W. None of that is large individually.

Then there is heating, which follows the same pattern as everywhere else on this site: a 2kW heater used for an hour before a winter session costs more than the rest of the session combined, and exceeds what a plug-in device can produce even at its summer peak. If you train in the morning or at lunchtime through the lighter months, solar covers a real share of the session. If you train at 6am in January, it covers none of it.

EV charging: the honest answer

This is the question garage owners ask most, so here it is plainly. An 800VA plug-in solar device cannot meaningfully charge an electric car.

At full output it produces 800W. A domestic 7kW wallbox draws nearly nine times that. Even a granny cable on a 13A socket pulls about 2.3kW — three times the device's maximum. Across a genuinely good summer day the whole device might generate 4–6kWh, which is somewhere in the region of 15–25 miles of range in ideal conditions, and considerably less in a British winter.

What a plug-in device does do, quietly, is offset the household background load while the car is charging, so a slightly smaller share of that charge comes from the grid. Useful, but not the headline anyone wants.

Mounting on a garage

• Garage roofs are usually the strongest and least shaded surface available — better than a shed and often better than a garden room.
• Flat felt or asphalt roofs suit ballasted tilted frames that need no penetrations at all.
• For a detached garage, check there is a suitable socket the device can plug straight into. Extension leads are not permitted — see the installation guide.
• Integral garages are easiest of all: the panels go on the roof and the plug goes into a socket already on the house circuits.

Is it worth it for a garage?

If the garage holds a freezer, a fridge or anything else that runs continuously, yes — that steady daytime draw is what turns generation into savings. If the garage is used occasionally for a car and some boxes, the solar still helps, but it is really offsetting the house rather than the garage; the roof is just a convenient place to put panels.

Either way, the device stays within 800VA AC and 2,000Wp of panels, one per household, connected directly to a socket and registered after installation. See rules and limits, and how much plug-in solar saves for the annual figures and the assumptions behind them.