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The panels are up, the battery is charged, and the fridge still will not run, because the power coming off the panels is not the kind of power the fridge can use. That is the moment the question of inverter for solar panels price stops being abstract, because an inverter is the part that turns battery power into household power, and its price follows its size and its features. A small inverter that runs lights and a phone charger costs less than a large inverter that runs a fridge and a well pump, so the right question is what size fits the loads you plan to run. This guide walks through each cost driver in turn.
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Inverter for solar panels price: the quick answer
A small inverter that runs lights and a phone charger costs less than a mid-size inverter that runs a mini fridge, and a large home backup inverter that runs a full-size fridge costs more again. The main cost drivers are the continuous watts, the surge capacity, the wave type and the extra features. Pure sine wave inverters cost more than modified sine wave inverters of the same size, and an inverter charger that also charges the battery costs more than an inverter alone. The rest of this guide breaks down each driver so you can see where the price goes.
Wattage sets most of the price
The inverter turns battery power into household AC, and its continuous watts set the size of the loads it can run. A small inverter holds enough output for lights, a phone charger and a laptop, while a large inverter holds enough for a fridge, a fan and a well pump through an outage. A unit with much larger output costs much more than a unit with small output, even when the brand and the features match. List the loads you plan to run and add up their running watts, rather than picking an inverter by its headline figure, because a headline figure can hide a small continuous output. Check the continuous watts and the surge capacity in the listing, and compare inverters on those figures. See the best inverters for a refrigerator for units that can start a compressor.
| Inverter size | Suits | Notes |
|---|---|---|
| Small portable inverter | Lights, phone charger, laptop | Light to carry, plugs into a car outlet |
| Mid-size inverter | Mini fridge, fan, router | Covers an overnight outage for small loads |
| Large home backup inverter | Full-size fridge and more | Needs a large battery bank and thick cables |
Pure sine wave costs more than modified sine wave
Inverters make AC power in different wave types, and the wave type shapes the price. A pure sine wave inverter makes smooth AC like the power from a wall outlet, and it runs fridges, motors and electronics with controls without trouble. A modified sine wave inverter makes a rougher wave, and it costs less than a pure sine wave inverter of the same size, but some loads run hot or buzz on it, and some electronics with controls will not run on it at all. If your loads include a fridge, a well pump or anything with a motor or a control board, a pure sine wave inverter is the safer choice. See pure sine wave vs modified sine wave inverter for a side-by-side look at each wave type.
Surge capacity and extra features
Surge capacity is the short burst an inverter can give when a motor starts, and it matters as much as the continuous watts. A compressor fridge pulls a short spike when it starts, so an inverter with strong surge capacity costs more than an inverter with weak surge capacity. Extra features add to the price as well: a remote switch that lets you turn the inverter on from a distance, a display that shows watts in and watts out, and a built-in charger that refills the battery from a wall outlet. Check the surge capacity in the listing, and match it to the startup draw of the largest motor you plan to start.
How to work out what size you need
Start by listing every load you plan to run, from the phone charger to the fridge, and note the watts each load draws. Add up the running watts of everything you plan to run at the same time, and allow for the startup draw of the largest motor on the list. Then check the continuous watts of the inverter against that total, and check the surge capacity against the startup draw. A watt meter between the load and the outlet measures real use over a day, which gives a better figure than the label on the appliance. See the best watt meters for options.
Ways to spend less without buying the wrong unit
The simplest way to spend less is to buy a smaller inverter, so size the inverter to the loads on your list and skip capacity you will never use. An inverter without a built-in charger costs less than an inverter charger of the same size, and you can add a separate charger later when you need it. Older models cost less than the newest model in a line, so check whether the new features are worth the extra price for your use. Avoid buying an inverter that is too small for your loads: an inverter that shuts off when the fridge starts is no bargain, and replacing it costs more than buying the right size at the start.
FAQ: power away from the grid
Do I need a pure sine wave inverter?
It depends on your loads. A pure sine wave inverter runs fridges, motors and electronics with controls without trouble, while a modified sine wave inverter costs less but can make some loads run hot or buzz. If your loads include anything with a motor or a control board, a pure sine wave inverter is the safer choice.
What size inverter do I need for a fridge?
Match the inverter to the running watts of the fridge plus the startup draw of its compressor, and check the surge capacity as well. A small inverter can run a mini fridge, while a full-size fridge needs a larger inverter with strong surge capacity. Add up the watts of everything you plan to run at the same time before you buy.
Can an inverter run a whole house?
A large inverter with a large battery bank can run many household loads, but it cannot run everything at the same time. List the loads you need during an outage, add up their watts, and size the inverter and the battery bank to that list. A licensed electrician should install any inverter that connects to home wiring.
How long does an inverter last?
An inverter lasts longer when it runs well within its continuous watts and stays cool and dry. Heat, dust and overload wear it down, so mount it where air can move around it and keep it out of damp places. Check the warranty in the listing, and look for a unit with a fan or a heatsink that keeps it cool under load.
What is the difference between an inverter and an inverter charger?
An inverter turns battery power into household AC, while an inverter charger does that and also charges the battery from a wall outlet. An inverter charger costs more than an inverter alone, and it suits a setup where the battery needs charging from the wall as well as from the panels. If your panels already charge the battery, an inverter alone may be enough.
Related solar guides
See the best inverters for a refrigerator, the best portable power stations for home backup, the best watt meters and the pure sine wave vs modified sine wave inverter. See every controller and inverter guide on the site.
