If it’s your first time off-grid and you’re used to mains grid power, there are a few changes you’ll have to make to adapt to solar power. If you’re already off-grid and are now making the switch to solar power, you’ll already be familiar with this list!
An off-grid solar power system can generally handle most of your day-to-day electrical needs if you’ve got the right kit. But there are a few things that aren’t recommended for use on solar, because they use a lot of power, and could leave you with no energy for other things you need.
The key items to be aware of is anything intended to produce heat – heaters, cooktops, hot water cylinders etc. These are the main reason why off-grid solar quotes from most companies are so high! But they don't need to be if you're willing to adapt your lifestyle a little.
Heating and Air Conditioning
Things like heat-pumps and electric heaters chew through power like crazy, and since you’re more likely to be running them in winter when there’s less sun, you won’t have a lot of energy to waste.
A cheap 2000W fan heater used for an evening (6 hours) will use approximately 12KWh – which is more than our Freedom Kit is expected to produce daily in winter! Even an efficient panel heater on minimum (using 750W) will still use 4.5KWh, more than half of the expected output of the Freedom Kit.
When you’re off-grid, your best bet for heating up a room is gas heater or woodburner - both have advantages and disadvantages. Gas heaters can come in smaller, lighter sizes with lower initial costs, but have ongoing fuel costs, can’t be used unsupervised, and create excess moisture. Woodburners dehumidify, have cheaper running costs, can produce a lot of heat, can be cooked on, and tend to look a lot nicer, but they take up a lot of space, are heavy, and cost more initially. Diesel heaters are also an option, similar to gas.
Hot water cylinders, just like heaters, use a lot of power and tend to run for at least a few hours a day. A typical water heater runs at 3000W and running for about 3 hours a day will use 9KWh. Even over the summer months, heating water will put a significant dent in the power you have available. This also applies to spa pools – even a modern one will use about 6KWh a day, so we recommend taking it off solar and using an alternative method for heating water.
There are a few different options when it comes to non-electric water heating. First is evacuated tube solar collectors – cold water is pumped from a water cylinder into an array of black tubes (usually on a roof), where it’s heated by the sun and returned to the cylinder, using no fuel and only a little power to run the controller and pump. You can also use a continuous flow gas heater (or califont), in which water is stored cold and heated on demand. A wetback is a great option if you’re already running a woodburner, as it runs water through pipes in the back of the firebox to heat it.
Electric ovens and stovetops, just like water and room heaters, use far too much power to be viable on solar. The average oven runs at 3000W, and hobs run between 1500-3000W. Both tend to run for more than just a few minutes, especially at night and during winter when there’s less power to go around. Benchtop ovens, hotplates, and slow cookers are all power-hungry as well, so best to avoid using these too (though once you're familiar with your system you may consider using them in summer if you're confident you have adequate power).
As with water and heating, the best options for cooking are gas and woodburning, with options ranging from an outdoor BBQ or a campfire, to a fully plumbed indoor oven or cast iron woodstove. Gas will typically require a 9V battery for spark, depending on the model you choose.
Electric Vehicle Charging
It depends on the exact make and model of EV you’re running, as well as your usage patterns, but you will likely be using about 9KWh a day to charge an EV. We’ve had several people ask us about switching just their EV charging to solar, and it’s simply not that practical. To support EV charging off the grid, you will need to run a significantly larger solar kit, as the only alternative would be a diesel generator! Generally, people running an EV are on the grid and looking to save money on their bills, so it’s less likely to be a problem off-grid.
Other high draw items you might not think of:
Clothes dryers average about 6KWh per use, so it’s best to switch to an alternative method - simply hanging them on the clotheslines or an airing rack.
Hair dryers can use a lot of power, typically using 800-1800W when heating, but can also use as little as 70W when not heating. This is one appliance you can continue to use if you’re aware of your usage and use the heating functions for a minimal amount of time.
Pool pumps are easy to overlook, as they’re not used for heating, but can often run between 500-2000W depending on the horsepower and running for 24 hours means they’ll chew through a lot of power. Your best bet here is to make sure you’re using the lowest horsepower pump as is appropriate for your pool, and only run them for the minimum amount of time as is necessary (typically 8 hours). Turning them off for winter is highly recommended.
Also, for similar reasons, we recommend using a generator instead of solar to power:
- Well pumps
- Bore pumps
- Air compressors
- Drop/Table saws
- Most cable power tools - we recommend switching to cordless, as a solar kit can be easily used to charge batteries
Items that may be okay:
Certain higher draw items may be okay to run on solar as they are typically only used for a short time. They may also be fine in summer when you have a surplus of power. These include:
- A small circular saw
- Small slow cooker
Technically all these things can be run on solar, but they will require an oversized solar kit, so we recommend finding alternative methods wherever you can. If you’re looking to be as efficient as possible with your solar power, look to eliminate things you don’t really need, or shift them to gas or woodburning. You may also choose to keep these items and run them using a petrol/diesel generator.
If there’s something you’re not sure about that we haven’t mentioned here, it’s easy to work out yourself. Find out the wattage of the item you want to use and multiply that by the number of hours you will use it. For example, a 1000W appliance will use about 166Wh when run for 10 minutes (1000x0.16), and 2000Wh when run for 2 hours (1000x2). Then you just take the estimated daily Wh for a kit and see if you can fit that much power use into your day alongside your other appliances.
There are a few exceptions to this rule, such as fridges, that don't continuously draw the same amount of power. For these, check out the energy star rating to see how many kWh they use a year, and divide by 365 to find the daily usage! We’ve done a lot of example calculations already that you can use as a guide, so make sure you check those out on our Kit pages.
And, as always, feel free to get in touch with any questions!