Not everyone wants to power the whole house off solar. A lot of people just want the basics covered: keep the fridge cold so the food does not spoil, keep a few fans turning, and keep the lights on. That is a modest ask, and it needs a modest system. Here is the rough size, and why one appliance decides most of it.
Add up what the essentials actually draw
The trick is to think in watts and in watt-hours over a day, not in vague feelings about how much a fridge “uses.”
A typical fridge draws somewhere around 100 to 400 watts while the compressor runs, but it does not run all the time, so over a full day it uses roughly 1 to 3 units of electricity. A ceiling fan is light work, about 50 to 75 watts each. LED bulbs are almost nothing, around 10 watts apiece. So a fridge, three or four fans and a handful of LED lights might use something like 3 to 5 units across a day, with the fridge eating most of it.
The rough system size
To cover that with solar, you take the daily energy need and divide by the hours of strong sun you can count on, which is about 5 a day here, then add a margin because real conditions are never perfect. For the essentials above, that points to roughly 1 to 2 kilowatts of panels. It is worth oversizing the array by 25 to 30 percent so you still cover the load on cloudy days, which we get into in what happens to solar production on a cloudy day.
If you only need the essentials during the day while the sun is up, panels and an inverter can do it. If you want them to stay on at night or through an outage, you also need a battery to store the daytime surplus, which is the part most people actually care about. We size that side in battery backup sizing: keeping the essentials on through an outage.
Why the fridge sets the size
Here is the catch with the fridge. When its compressor kicks on, it briefly pulls several times its normal running wattage, a quick jolt called the startup surge. The inverter has to be big enough to swallow that surge without tripping, even though the steady draw afterwards is small. That is why a system for a fridge is sized more around the surge than the average, and why a too-small inverter will keep cutting out every time the fridge cycles. We explain that in what size inverter do you need for your home. You can read more about how a fridge compressor works on the Wikipedia refrigerator page.
The honest takeaway
For just a fridge, fans and lights, a small system in the 1 to 2 kilowatt range with a modest battery covers it comfortably, and the fridge, not the lights, is what really sets the size. Start by listing what you must keep on, get the real wattages off the labels, and size from there. It is a far cheaper entry point than powering the whole house, and for many homes it is exactly the right place to begin.
Related reading
- Battery backup sizing: keeping the essentials on through an outage for the storage side of an essentials system.
- What size inverter do you need for your home? for handling the fridge startup surge.
- How many solar panels do you need to run a whole house? for when you want more than the basics.
- Solar system planning to size a system around exactly what you want to keep running.
What size solar system runs a fridge, fans and lights?
For just those essentials, a system of roughly 1 to 2 kilowatts of panels with a modest battery covers it comfortably for most homes. The fridge uses most of the energy, while fans and LED lights add very little. The exact size depends on your fridge and how many hours you want everything to stay on.
How much power does a fridge use?
A typical fridge draws around 100 to 400 watts while the compressor runs, but since it cycles on and off rather than running constantly, it uses roughly 1 to 3 units of electricity over a full day. That makes it the biggest single draw among the basic essentials, so it largely sets the size of the system.
Do I need a battery to run my fridge on solar?
Only if you want it to stay cold at night or through an outage. Panels and an inverter can run the fridge during the day while the sun is up, but a battery stores the daytime surplus to keep it going after dark. For most people the whole point is overnight and outage cover, so a battery is part of the plan.
Why does the fridge decide the inverter size?
When a fridge compressor starts, it briefly pulls several times its normal running wattage, a jolt called the startup surge. The inverter must be large enough to handle that surge without tripping, even though the steady draw is small. A too-small inverter will keep cutting out each time the fridge cycles on.
Can fans and lights run on a very small system?
Yes. LED bulbs use around 10 watts each and ceiling fans about 50 to 75 watts, so lighting and fans barely register against a fridge. If lights and fans were all you needed, a very small system would do. It is the fridge that pushes the size up into the 1 to 2 kilowatt range.
How do I work out my own essentials system size?
List exactly what you must keep on, read the wattage off each appliance label, and add up the daily energy they use. Divide by the hours of strong sun, around five a day here, and add a margin for cloudy days. A proper assessment turns that into the right panel, battery and inverter sizes.
The next step
If keeping the fridge, fans and lights on is all you need, a small system does it without breaking the bank. Get a free quote or tell us what you want to keep running, and we will size the panels, battery and inverter to match.