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The difference between kW’s and kWh’s when going Solar

The difference between kW’s and kWh’s when going Solar

Not knowing the difference between kW's and kWh's makes it really hard for YOU to compare solar proposals, to understand your bill and to ultimately make sure you get the right solar solution.

Today we’re talking about the one big thing that’s coming up all the time that makes it really hard for YOU to compare solar proposals, to understand your bill and to ultimately make sure you get the right solar solution.

Now, that one thing is The difference between kilowatts (kW’s) and kilowatt-hours (kWh’s).

Power is measured in Kilowatts (kW’s).

Energy is measured as kilowatt-hours (kWh’s).

I like to think of them like a hose and bucket of water, the power (kW) is the water coming through the hose and the water that accumulates in the bucket is the energy (kWh).

The more power (kW’s), the bigger the hose and the more water that accumulates in the bucket, the energy (kWh’s). 

Now, where you will see Kilowatts (kW’s) mentioned is in the size of your solar system, and the size of other common appliances like your split system air conditioner. You’ll also see it in the amount of solar pre-approval for export that you get if you get in the Powercor region. Which includes Woodend, Gisborne, Macedon, Riddells Creek and Kyneton. If your property is the PowerCor area, you need to get pre-approval to export power to the grid, get at least five Kilowatts (kW’s) if they have single phase power.

You’ll see kilowatt-hours (kWh’s) on your bill. Each time you get a bill whether it be for a month or quarter, you’ll have an accumulation of kilowatt-hours (kWh’s) and you’ll be charged a certain rate per kilowatt-hour (kWh). You might use 300 kilowatt-hours for the month and be charged 30 cents per kilowatt-hour (kWh). 

When you have solar installed, you can export the power you don’t use during the day back to the grid. This shows up on your bill as kilowatt-hours (kWh’s) just like your usage, which you receive a credit for based on how many kilowatt-hours (kWh’s) you have supplied to the grid. 

Why is this so important?

Now, this is so important because they’re very different things and if confused you can end up with a completely wrong sized solar system.

Now, if you use eight kilowatt-hours (8 kWh’s) a day, you do not necessarily need an eight-kilowatt system (8kW). Very different…

How do you know how many kilowatt-hours (kWh’s) you use a day?

On your bill, no matter which retailer you’re with, you will see average kilowatt-hours(kWh’s) per day. (It’s usually around the same spot that you have an average cost per day).

Now, everyone varies so one person living at home on their own, who’s at work during the day might use five kilowatt-hours (kWh’s) a day. Whereas a family with four kids, where mum or dad work from home, who have a pool (lucky them) might use 50 kilowatt-hours (kWh’s) a day.

Now, if you use 32 kilowatt-hours (kWh’s) in a day, to produce the same amount of power with your solar system,  you would need around an eight-kilowatt system. Whereas, to produce eight kilowatt-hours (8 kWh’s) you would only need a two kilowatt (2kW) system.

So they’re very different things…

One of the biggest mistakes we see people making is comparing the price of different size solar system, not understanding the different results and saving they will receive long term.


For example a 5kW system may be lower cost now, compared to an 8kW system, however, the output of the larger system can often result in more savings long term and better return on investment. So it’s important to compare apples with apples.



Solar can deliver amazing results when installed well and design to suit you.

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