We’re all painfully aware that electricity prices are going up. Solar is a powerful way to protect your hip pocket from rising energy costs. But installing a whole house solar generator is not always the right solution. You can easily end up paying more for power than you would on the grid. But that doesn’t mean a solar generator is not for you. In this post, we share: 1) why a whole house solar generator is overkill, 2) three real life alternatives to still get the solar solution you need, and 3) four recommendations to save you thousands on a solar battery.

Is a whole house solar generator what you really need? 6 key takeaways

1. Let’s start with, the larger the solar generator (in kWh), the bigger the cost.
2. If you’re a big winter time energy user, you need a bigger solar generator and that will be very expensive. We explain why below.
3. The secret no-one talks about is that you don’t need a whole house generator unless you want to go off grid. Getting one is overkill (because of the cost of batteries) if you’re not going off grid. You’ll likely end up paying more than you pay for grid power.
4. You don’t have to overpay for your solar power. Solar companies will always want you to upsize. But we share 3 awesome alternatives to a whole house solar generator, that will still give you what you need.
5. Battery costs are declining. There are smart and efficient ways to take advantage of this and still get a solar generator.
6. You can save thousands with the 3 recommendations at the end of this article. On the other hand, getting the wrong size generator can cost you more for electricity than the power grid.

What do we mean by ‘whole house solar generator’?

A whole house solar generator is a rooftop solar PV + battery storage system that provides enough power to run your entire home, 24 hours a day, 365 days a year.

The solar panels generate power from the sun of course. That energy feeds into your home through a device called an inverter. If the solar system makes more power than you need at any one time, this extra energy is stored in your battery system.

Your battery then delivers power into you home at night. Or any time the solar system isn’t making enough power to meet your needs. That can happen on cloudy days or in poor weather.

Because it supplies ALL of your power ALL of the time, a whole house solar generator can often include a backup generator. One that works rain hail or shine.

Diesel, petrol and gas backup generators are popular because they’re not weather reliant. The backup is there to give you power when there are multiple days of bad weather. Remember, if the sun’s not out, there’s no power for you or your battery.

A solar generator can be grid connected or off grid. If its on the power grid, the poles and wires act as your big backup energy source. That means you don’t need a fuel based backup generator.

Can a solar generator power a whole house?

Yes, a large solar generator can power an entire house. It’s designed to do just that.

Solar PV panels and solar batteries are modular. They can be joined together (the panels and the batteries) to make a more powerful generator. This means single modules can be scaled up to provide enough power for a whole house.

It’s common these days if you live in rural and remote areas without the power grid to run your entire home with a solar generator.

It’s rarer to see a whole house solar generator where there is a power grid.

There are good financial reasons for this.

When is a whole house solar generator the best choice?

The best financial benefits from a solar generator come if you’re in an off grid area or at the edge of the power grid.

If there is no grid around you, there are generally 2 options.

You can pay the cost to run powerlines to your home from the nearest electricity network connection point. This can happen if you live at the end of the power grid (‘edge of grid’).

But it can be very expensive.

Or you can generate and supply your own power. The most common way to do this is with a whole house solar generator.

A powerful solar generator is not a cheap solution. While solar PV by itself is now cheaper than grid power, battery storage systems are not yet at ‘energy price parity’ (where the total cost of electricity over the life of the solar battery is the same price or cheaper than the grid).

Batteries are still an expensive piece of kit.

But running your home with a solar generator can be a cheaper solution than paying the power company to run new power lines to your home. Not only do you have to pay for the powerlines, you have to keep paying for your grid power.

With a solar generator, the only real cost is upfront. After the system pays it self off (in avoided grid power costs), the power is free.

The top 4 reasons people want a solar generator in 2022

Queensland is well know for leading Australia in solar panel installs. More than 40% of homes have solar. But only 15% have some kind of battery storage.

According to the Queensland Household Energy Survey 2022, here are the top 4 cited reasons Queenslanders want solar generators (solar with batteries) for their home:

• To reduce the amount of power they use from the grid (54%)
• To reduce the their power bill (49%)
• For backup power in storms and outages (46%)
• To be less reliant on the power grid (43%)

The secret no-one talks about is that you don’t need a whole house generator to meet these objectives.

Only 22% of people said they want a solar generator to prepare to go off grid.

And these are the people that a whole house solar generator is designed for.

Why only them? One look at how much power we use gives us the answer.

How much power do you need to run a whole house?

Why is how much energy we use relevant here?

Well, the amount of energy we use determines the size of the solar generator.

Size (in kilowatts) determines the capital cost.

The cost largely determines how much you end up paying for your power over the life of the generator (the cents per kilowatt hour cost). Because there few ongoing costs with solar generators.

This is how the financial bit works.

If a whole house solar generator is designed to run a house 24/7, 365 days a year, how much power is that?

Well it’s a vastly different amount depending on where you live in Australia.

Just take a look at the typical household energy use in Queensland vs Tasmania. Tasmanian’s use almost double the energy of Queenslanders in their peak season. For Queensland that’s summer, but for Tasmania its winter.

What this all means is, the cost of your generator will vary significantly depending on your energy use. And that varies based on where you live.

So exactly how many solar panels and batteries you need to meet a typical household’s daily energy use in Queensland and Tasmania?

And what will all new kit that cost you?

What size solar generator to power a whole house

Now we know how much power a typical home uses, how many solar panels and batteries do we need to make that much power? To run our whole house 24/7, 365 days a year?

There are 4 important factors to plan for when sizing a generator:

1. The purpose of your solar generator. Its critical to working out what size solar generator you need. We show why down below.
2. Nighttime energy use. We typically use around 70% of our power supply at night. A battery has to be big enough to cover that.
3. System losses. Solar batteries lose energy when they operate. If we don’t account for that, our system may be too small to power our needs.
4. The weather. This determines how much electricity our solar panels are expected to generate. States like Queensland and SA have higher output from their solar systems. Of course they do, there’s more sunshine each day! In sunny locations, you can get away with a smaller solar system.

Now lets factor these things into our calculations.

Want to know how we worked out these numbers? There’s a quick step guide in this post ‘How many solar batteries are needed to power a house.’

How many solar batteries does it take to power an entire house?

Here’s the size battery needed for a typical to cover all night time energy use. It assumes you and your whole house solar generator are still connected to the power grid.

The battery size below is sufficient to run your whole house, and provide 2 days of backup power in poor weather. It assumes your solar PV won’t generate during those 2 days. So the battery storage is big enough to power your whole home for 2 days.

Number of Tesla Powerwalls is just a proxy unit of measure. It goes without saying, you can’t buy 0.7 of a battery! You’d need to size up, or chose another make of battery better sized to your needs.

How many solar panels does it take to power an entire house

Here’s all the calculations showing how many 350 watt solar panels needed for the same situation – to run your whole house and charge the batteries above within a day.

For an off grid solar generator, you need enough solar panels meet your power needs AND keep your battery charged, prepared at any time for few days of bad weather.

How much does a whole house solar generator cost?

One Powerwall was around $13,000 installed, at the time of writing.

The national price for solar power is $0.97 per watt.

Here’s what a whole house solar generator could cost you, using our base unit numbers and costs:

Queensland looks affordable if the alternative is upgrading the power lines to run them to your door. But in Tassie it’s going to cost a bomb. Because winter power needs are high. And just when you need more power, the sun’s not out much.

Are these actual costs? No, they’re not.

Can you get a large solar generator for cheaper than this? Sure. You get deals, negotiate, use different panels and batteries.

The point is to show you how much you could be up for with a big solar generator. And point out the disparity in costs across locations and climates.

So now it’s time to show you why a whole house solar generator is overkill, unless you have to go off grid.

3 awesome alternatives to a whole house solar generator

We can think of 3 legit alternatives to a whole house generator that still meet those aims of people considering buying a solar battery in the first place.

1. The first alternative is a whole house solar only system
2. The second is a solar generator for nighttime
3. The third is a solar generator for backup

But first, lets look at what the difference is between each of these.

‘Whole house solar generator’ vs a ‘solar generator’ vs a ‘whole house solar only system’

What’s the difference?

We’ve already said a whole house solar generator is a solar battery that runs your whole house 24/7, 365 days a year. It can be connected to the power grid, or off grid. It often includes a all weather backup generator, just in case.

A solar generator is a solar battery that is connected to the power grid and your home. Its a smaller solar battery that meets some of your home energy needs during the day and at nighttime. The power grid meets the rest.

A whole house solar system is a large solar PV system only (no battery), that generates enough power to meet all of your daily energy needs. But because you use power at night, the solar PV is not actually meeting your power needs 24/7. It only generates in the day time. You have excess solar power in the day that you sell into the power grid due to the large system size.

Now we know what they are, lets look at the size and cost of each alternative. Compared with what you’d pay for a whole house solar generator

1. Whole house solar PV system – size and cost

Adding solar PV(only) to your home is the most cost effective step you can take to protect your hip pocket from rising power prices in 2023.

Solar power is below grid parity, meaning it’s cheaper than grid power. You might pay around 10 c/kWh for your solar power. That compares with 30 c/kWh + for grid power after coming price hikes.

And it’s around 10% of the cost of whole house solar generator.

2. Solar generator for nighttime – size and cost

This is a solar generator with a battery designed to meet 70% of your electricity needs – at nighttime. The only difference between options 1 and 2 is the battery. So lets work out the battery size and add some est. battery costs.

Total costs projections for your night time solar + battery + inverter (around $1500) system:

3. Solar generator for battery backup – size and cost

This system has a bigger solar battery. It is designed to run your night time power load and give you 1 days backup power in a power outage.

Here are the cost estimates of a backup solar + battery + inverter system:

How much can you save with the right solar generator?

It’s time for the big reveal. The cost comparison. Here’s the savings we’ve been talking about, demonstrated:

4 Tips to take advantage of declining battery costs

1. Start with solar PV. Make sure you future proof what you install so that you can add batteries and more panels. Funnel your electricity savings into a battery system fund!
2. As costs come down, add a battery to your solar system. Start with a battery that will cover your night time load. Get a modular battery system that you can add to over time. Get a battery that has UPS (uninterrupted power supply) capability.
3. As costs decline further, add units to your battery system. Have an electrician to wire your home for UPS. Now you have backup power in outages.
4. Take the final step off the grid if you want to. By this point, battery storage prices are likely to have declined further. make it more affordable to do so. And marginal cost of scaling up your existing kit to going off grid becomes affordable!

Remember in all of this that batteries have a lifespan. Good lithium ones will last you 10 to 15 years. Factor this into your incremental move into solar power.

In a Nutshell

It’s good for your hip pocket to get the right size solar generator. A whole house solar generator ain’t always it. Instead consider your aims and size your solar battery to that. Is it to use your solar power at night? Or for backup in a power outage? The big kahuna solar generator will cost you a pretty penny right now. You may even end up paying more for power than you would on the grid! The good news is, solar batteries are modular. You can add to your system costs go down. And this incremental approach a more cost effective way to save money, go green and maybe even step off the power grid!