Home solar question, what upgrade path?

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Loismustdye

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#324406 4-Apr-2026 16:29

To avoid trawling through the solar mega thread….

We are waiting on some pricing for solar for our home but we’re just wondering the logic of what upgrade path to take first.

house is 2009 build, double glazed etc of approx 200 sqm excluding the attached garage.
The main reason for this is to remove our reliance on gas, as we currently have a gas fireplace (currently with a fault so we use our 2 heat pumps instead ( installed after winter last year), gas cooktop (free standing oven but is 90cm wide so will be spendy to upgrade to induction) and gas infinity hot water. Our gas usage is 2-300 kw monthly outside of winter and over winter that jumps to over 1000 kWh monthly - last years winter bills were over $100 extra a month for gas alone, this years will be more due to the price increases. And that $70 a month connection fee for gas grinds my gears :-)

2 adults and 2 teens in palmy, and with contact for both gas and power using the nightly free power 9pm - 12am.

I am assuming the solar will come in around 20 ish panels and a battery.

With those of you that have made the move, did you get rid of it all at once or piecemeal? And in our situation what would you upgrade first outside of the solar install? To manage costs a wee bit we were looking at the install first and then replace either the oven or the infinity water as finances allowed.

Is it worth swapping to a different power company with buyback rates once installed or stick with the above until the gas appliances completely removed?
I should add my wife works for an electrical firm so our costs will be a little less than that of the public.

Thanks

Updated picture with roof orientation (red arrow north) and roof pitch (declines in direction blue arrow).

to reduce costs a bit we are potentially looking to leave the hot water upgrade for the time being as I’m not really wanting to go into $40k+ costs t present.

suggestions are 30 panels with/without battery, and I assume that many panels due to the direction and pitch of the roof.

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#3478041 4-Apr-2026 17:33

Hot water and heating are usually the highest energy consumers. Given you're already using electricity for the heating, then a move to electric water heating would probably be the next thing to do, especially if the teenagers use a lot of hot water.

A larger cylinder will store more energy; if you put it on a timer or other logic to heat during the day when the sun is out that will probably get the best return.

EDIT: Consider if your cooktop can be modified to use bottled gas and that will drop your monthly connection fee.

timmmay

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#3478043 4-Apr-2026 17:38

A year ago I paid about $15K for 21 panels with no battery. With a battery it'd be more like $25K+. I'm not sure a battery is worthwhile, it depends how much you get paid for power and how much you pay - we pay something like 22c/kwh and get paid 18c/kwh, the 4c/kwh differential means payback time is high. We use the grid as a battery.

Hot water tank is where I'd start, it's easy to schedule it to heat when it's sunny, even a basic timer will be good enough. Heat pump hot water... maybe for a new purchase. Their reliability is probably improving. Double win there, solar and 3X efficiency.

Indoor heating is pretty easy too, a timer can pre-heat the house in winter.

At that point you'll be paying $70 a month just for the hob so it becomes easier to justify replacing, or maybe using bottles. I find cooking only partly uses solar, by the time we want to cook the sun is down or weaker and the oven uses a ton of power, a battery would be helpful here but just use the grid.

Loismustdye

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#3478269 5-Apr-2026 13:04

RunningMan:

Hot water and heating are usually the highest energy consumers. Given you're already using electricity for the heating, then a move to electric water heating would probably be the next thing to do, especially if the teenagers use a lot of hot water.

A larger cylinder will store more energy; if you put it on a timer or other logic to heat during the day when the sun is out that will probably get the best return.

EDIT: Consider if your cooktop can be modified to use bottled gas and that will drop your monthly connection fee.

Thanks. I hadn’t considered moving to lpg for the cooktop, the oven has been in since the house was built so it may be a bit more difficult but will check my options.

we would be looking at the biggest cylinder we could get and ideally heat it during the day with the panels.

Loismustdye

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#3478273 5-Apr-2026 13:21

timmmay:

A year ago I paid about $15K for 21 panels with no battery. With a battery it'd be more like $25K+. I'm not sure a battery is worthwhile, it depends how much you get paid for power and how much you pay - we pay something like 22c/kwh and get paid 18c/kwh, the 4c/kwh differential means payback time is high. We use the grid as a battery.

Hot water tank is where I'd start, it's easy to schedule it to heat when it's sunny, even a basic timer will be good enough. Heat pump hot water... maybe for a new purchase. Their reliability is probably improving. Double win there, solar and 3X efficiency.

Indoor heating is pretty easy too, a timer can pre-heat the house in winter.

At that point you'll be paying $70 a month just for the hob so it becomes easier to justify replacing, or maybe using bottles. I find cooking only partly uses solar, by the time we want to cook the sun is down or weaker and the oven uses a ton of power, a battery would be helpful here but just use the grid.

We would likely head down the hwhp path with as big a cylinder as we could get ideally with an integrated app to set up timers etc.

interesting about the battery as I have wondered whether it’s of much use based on a 10kw only having $3 or so of stored power in it and whether it would be better to save that $10k and put it somewhere else.

We got mhi heat pumps installed with the associated app so can set daily timers for them both to make use of the sunlight hours. Once the gas goes we will swap out the gas fireplace for a floor console from them as well.

the $70/month just for the connection is my main reason for wanting to get rid of it, that $70 would be more useful imo in going towards the solar install or even towards electricity costs.

the post above yours mentioned converting to lpg so we will have a look at that although if that’s going to be a few thousand $ then I would likely just put that into a whole new oven (likely around $6k or so to fit our space).

Stu1

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#3478293 5-Apr-2026 15:29

your gas heating has a fault so worth replacing , unless your infinity is broken wait to it breaks. HWP are a tough ROI at least 10 k to install and often need replacing in 7 years. You could get three infinity’s for that price even with gas prices I will convert to bottles over losing my continuous hot water . Just not worth it unless it’s at end of life. The money you save on solar covers can offset your gas charge

Loismustdye

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#3488593 8-May-2026 07:49

Got our price from my wife’s contact and consists of 30 460w panels, sigen 10kw inverter, gateway and 10kw battery.

I want to knock $4-6k off the quote price as I have a set budget in mind (I only want to spend a set amount and the quote is slightly above that).

to reduce the cost are we better to knock off sufficient panels to reduce the price down? Or remove the battery?

the panels are meant to provide 17-18kwh annually based on the quote which I think is a tad optimistic.
2a 2c away during the day, as noted we have gas infinity and will be keeping this for the time being, so my thinking is to drop the panel numbers to enable utilising the battery during peak times and rely on grid export during the day to offset the energy bill somewhat. Cheers

(edited for correction of numbers)

BlargHonk

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#3488595 8-May-2026 08:25

I would look at the price difference between a standard electric HWC and extra solar panels compared to getting the heat pump hot water cylinder. Especially if you have the roofspace for lots of panels. 3x energy efficiency is great, but if the energy is next to free during the middle of the day?

richrdh18

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#3488599 8-May-2026 08:54

I'm in Palmy and have 9.6KW system, 22 Panels, 13 NNE and 9 NNW facing, 10KW Bty for 27K. I have gas fireplace, hotwater and hob. I havent paid a bill since changing to Power Edge in Sep '24. Since Sep have build up 870 in credit and now i can turn on our underfloor heating (electric). I would like to move away from gas but that would be another 15 -20k i'd imagine, so just putting up with the daily fee. Gas usage is actually minimal but the daily fee is more that the gas we use. I feel that even changing to bottled gas there still is a lot of gotyas, like bottle rental, termination/disconnection fees, refilling so in the end wont be that much cheaper. Having the Bty has been a saviour though, that keeps the overnight draw from the grid down to near nothing. Loving solar now, and its all about not having to pay the man... Even on the most overcast days we still produce enough power to run the home.

wellygary

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#3488600 8-May-2026 09:03

Loismustdye:

Thanks. I hadn’t considered moving to lpg for the cooktop, the oven has been in since the house was built so it may be a bit more difficult but will check my options.

The Oven is likely electric, with gas hobs on top, our holiday home as a similar cooktop and we run the hobs on 9kg bottles fine...

Loismustdye

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#3488605 8-May-2026 09:40

richrdh18:

I'm in Palmy and have 9.6KW system, 22 Panels, 13 NNE and 9 NNW facing, 10KW Bty for 27K. I have gas fireplace, hotwater and hob. I havent paid a bill since changing to Power Edge in Sep '24. Since Sep have build up 870 in credit and now i can turn on our underfloor heating (electric). I would like to move away from gas but that would be another 15 -20k i'd imagine, so just putting up with the daily fee. Gas usage is actually minimal but the daily fee is more that the gas we use. I feel that even changing to bottled gas there still is a lot of gotyas, like bottle rental, termination/disconnection fees, refilling so in the end wont be that much cheaper. Having the Bty has been a saviour though, that keeps the overnight draw from the grid down to near nothing. Loving solar now, and its all about not having to pay the man... Even on the most overcast days we still produce enough power to run the home.

thats really nice to know, thanks. Can I ask who did your install to add to the list of installers? Your situation sounds a lot like ours however with better roof orientation than ours.

timmmay

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#3488607 8-May-2026 09:43

Solar panels are 25% efficient, whereas the older style systems that directly heat the water from the sun are apparently much more efficient. Might be worth considering, but not sure if it's economic and reduces solar panel count you can deploy which is more multi-purpose.

There's an opportunity cost using power you generated, which is the feed in tariff. If you have an old style hot water cylinder, like we do, you don't get the feed-in tariff for that power you use. We used 285kwh for hot water heating for 2 adults / 1 child in April, 320kwh last June.

Paul1977

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#3488611 8-May-2026 09:49

Loismustdye:

Got our price from my wife’s contact and consists of 30 46w panels, sigen inverter, gateway and 10kw battery.

I want to knock $4-6k off the quote price as I have a set budget in mind (I only want to spend a set amount and the quote is slightly above that).

to reduce the cost are we better to knock off sufficient panels to reduce the price down? Or remove the battery?

the panels are meant to provide 16-17k annually based on the quote.
2a 2c away during the day, as noted we have gas infinity and will be keeping this for the time being, so my thinking is to drop the panel numbers to enable utilising the battery during peak times and rely on grid export during the day to offset the energy bill somewhat. Cheers

I assume you meant 30x 460W panels (13.8kW total). What capacity inverter, I assume 10kW? If so that sounds OK to me. It's a fairly generous over provisioning of panels, but not crazy and would help generation in Winter so not a bad thing.

Assuming 13.8kW panels and 10kW inverter, and also assuming you are in an area where you are allowed to export up to 10kW, I'd personally drop the battery. That would be the most significant savings. Removing panels would save you very little. Then get on a plan with a good export rate. If you're limited to 5kW export, then that might change things a bit.

richrdh18

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#3488628 8-May-2026 09:55

Loismustdye:

richrdh18:

I'm in Palmy and have 9.6KW system, 22 Panels, 13 NNE and 9 NNW facing, 10KW Bty for 27K. I have gas fireplace, hotwater and hob. I havent paid a bill since changing to Power Edge in Sep '24. Since Sep have build up 870 in credit and now i can turn on our underfloor heating (electric). I would like to move away from gas but that would be another 15 -20k i'd imagine, so just putting up with the daily fee. Gas usage is actually minimal but the daily fee is more that the gas we use. I feel that even changing to bottled gas there still is a lot of gotyas, like bottle rental, termination/disconnection fees, refilling so in the end wont be that much cheaper. Having the Bty has been a saviour though, that keeps the overnight draw from the grid down to near nothing. Loving solar now, and its all about not having to pay the man... Even on the most overcast days we still produce enough power to run the home.

thats really nice to know, thanks. Can I ask who did your install to add to the list of installers? Your situation sounds a lot like ours however with better roof orientation than ours.

We purchased from Sunshine Solar but the installers were Star Delta Electrical from Kapiti who now offer their own solar solutions. We have a 5KW inverter. If I were to do it again, i'd go for more bty, slightly larger inverter and as many panels as your roof can handle. But hey, free power for the next 30 years and beyond.

Paul1977

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#3488630 8-May-2026 10:05

I'd missed the part in your post about the roof pitching down in the wrong direction for optimal solar. What is the pitch of the roof, and are they suggesting tilt mounts to improve the angle of the panels?

Dairusire

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#3488634 8-May-2026 10:36

So, we're sort of in the middle of the same as yourself.

We're in Hastings, 180m square ish and basically the exact same roof angle and direction.
We've got a wood burner for heating the house, but we're getting ducted heating/cooling done, as well as Hot water heatpump, which will then have us getting disconnected from Mains gas as we currently have infinity hot water.

All in for the ducted system, solar, and hotwater heatpump, we're looking around 45-47k.
We're lucky in that we can afford to do it all in one go.

We've found most Heatpump HWC quotes for a 250L-300L came back around $8-10k incl GST fully installed.
This is the one thing I've been wondering if I 'actually' need to do this. Our Infinity hot water is working perfectly fine, it's a lot of money to replace, for the only benefit being that we're no longer having lines charges and know that we're not getting a massive energy price increase at a providers or markets whim.

Ducted has been pretty variable in terms of costs. Averaging around $15.5k. That's for 4 bedrooms, a really large kitchen/dining space, and a big lounge. So 6 different zones.

The Solar system, we're just getting documentation on from Micromall for the Deye system, installation instructions etc. After having looked through all the solutions, considering the price and the fact it's got 20kWh of battery for 18k, which was 4k cheaper than a SigEnergy solution with 10kWh, it is worth it to me.

The below doesn't include installation, which is being done by two of my friends who are certified to do so, so account for that. I've found install quotes to be around 5-6k where you've provided the kit.

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