Solar options for home in 2022

Forums › Home Workshop DIY › Solar options for home in 2022 - 2026

1 | ... | 119 | 120 | 121 | 122 | 123 | 124 | 125 | 126 | 127 | 128 | 129 | ... | 150

226 posts

Master Geek
+1 received by user: 63

#3460207 10-Feb-2026 13:39

Paul1977:

I'm just not convinced on ROI of a battery,

EDIT: Forgot to mention, they are suggesting a Tesla Powerwall 3 for the battery.

Get a quote on a 48V battery system to compare ROI against the PW3. e.g. 16kW for $3499 there other suppliers in the ballpark too.

My biggest regret is going with a Fronius inverter which has only one very expensive DC battery option (otherwise its a great inverter). But still last time i did the calcs the ROI was very marginal, but very much depends on your individual usage patterns. I think you could get 20 years out of Lifepo4 these days (70% SOH after 8000 cycles at 1 full cycle per day = 22 years). I took my actual half hourly usage for 12 months with solar and looked at what peak and shoulder grid usage i had that could be replaced with battery to work out the return.

For a PHEV if they can charge at high rates like a full EV, then a smart charger that charges only from execess solar is a good investment too.

dukezoid

74 posts

Master Geek
+1 received by user: 15

#3460211 10-Feb-2026 13:52

Paul1977:

Another person here looking to install solar in Christchurch.

Harrisons were around yesterday and will be sending pricing through later in the week. Mainly looking at Harrisons because of the Aiko panels.

He suggested 16 panels and (I think) 8kW inverter if not going with a battery. I had been thinking of "oversizing" with 24 panels on a 10kW inverter to sell more excess back to the grid (and to generate more in winter), but he said that if oversizing it's better to do a battery as well. I'm just not convinced on ROI of a battery, and I'm not entirely clear why they'd suggest not oversizing if you don't have a battery? Will the battery realistically pay for itself before it needs replacing? And 13.5kWh doesn't sound like a lot of battery capacity to me (especially when that will drop as it ages)?

Our biggest power draw is our ducted heat pump, which is used during the day and evening for heating or cooling in Summer and Winter. Autumn and Spring is used a lot less. In Summer often don't put cooling on until after lunch. In Winter heating might be on all day (either turned down, or off, overnight and set to crank back up before we wake).

We have gas hot water & hobs and aren't realistically looking to change to electric in the short or medium term.

So, what are people's thoughts about oversizing without a battery?

Thanks

Paul

EDIT: Forgot to mention, they are suggesting a Tesla Powerwall 3 for the battery.

Solar 1 year in - started with 11kW panels 10kW inverter 16kWh battery. Just commissioned another 5kW panels, panels are cheap - oversizing (provided inverter can handle) is a no-brainer to me. More panels will help with energy independence in expensive (if on variable rate) winter months and export earnings in summer.

Battery ROI is clear depending on your pattern of use. I'd be getting off gas ASAP - health and its only going to get more expensive.

If budget constrained , and have space, there are installers in Chch commissioning used Leaf batteries with Darla's battery emulator. Incredibly cheap per kWh. If less budget constrained Sigenergy is pretty good for all-in-one HV battery solution with DC-DC future proofed

Paul1977

5171 posts

Uber Geek
+1 received by user: 2192

#3460228 10-Feb-2026 15:37

Thanks guys,

I thought our gas bills weren't too bad, but I don't have a frame of reference. Pricing for our LPG bottles has gone up, but we have a very efficient califont, so hot water + gas hobs runs us about $70 a month. Is that high? Health I'm not too concerned, the hobs don't get used excessively and we have a Lossnay ventilating the house.

The Harrisons guy indicated that Orion would soon be increasing their export cap to 10kW per phase. What "soon" means, and how he knows this - I have no idea. But if true that would seem to be less reason for a battery?

Powerwall 3 is obviously an expensive option, so I guess my question there would be: what are you getting for the extra cost compared to other battery solutions? I know it has the inverter built in, but I'm not sure I'd view that has an advantage as if the inverter dies out of warranty you presumably need to shell out for a whole new Powerwall. So, are there other benefits?

timmmay

20864 posts

Uber Geek
+1 received by user: 5350

Trusted

Lifetime subscriber

#3460230 10-Feb-2026 15:46

Paul1977:

He suggested 16 panels and (I think) 8kW inverter if not going with a battery. I had been thinking of "oversizing" with 24 panels on a 10kW inverter to sell more excess back to the grid (and to generate more in winter), but he said that if oversizing it's better to do a battery as well. I'm just not convinced on ROI of a battery, and I'm not entirely clear why they'd suggest not oversizing if you don't have a battery? Will the battery realistically pay for itself before it needs replacing? And 13.5kWh doesn't sound like a lot of battery capacity to me (especially when that will drop as it ages)?

We have 21 panels split between north and west facing, and a 6kw inverter... it's a little small, 7.5kw would give us a bit more generation at peak, but it's ok. 16 panels and 8kw seems like not enough panels or inverter is too large. We didn't get a battery, we pay 22c and get paid 18c, the difference is so small a battery is not worthwhile. We just sell to the grid, we had a $15 power bill last month. If we had spent thousands on a battery it may have reduced our bill to zero... not enough gain for us.

No problems with ducted heat pump + two other heat pumps being used all winter / summer.

timmmay

20864 posts

Uber Geek
+1 received by user: 5350

Trusted

Lifetime subscriber

#3460232 10-Feb-2026 15:48

Rmani:

I'm planning to install solar. Any recommended installers in Wellington? I did visit the website (seanz) suggested by @HarmLessSolutions. However, it gives me a long list of companies, unsure whom to go with.

We used Solarman. Happy with him, but their contracted installers scratched parts of our color steel roof to the point I had to paint the office roof, and when they found what they thought was rotten timber where we asked them to install the inverter they just moved along a bit rather than talk to us about it first. Inverter also slightly undersized I think but not bad. I would use them again but I would watch the installers much more closely.

dantheperson

226 posts

Master Geek
+1 received by user: 63

#3460234 10-Feb-2026 15:52

Paul1977:

Thanks guys,

I thought our gas bills weren't too bad, but I don't have a frame of reference. Pricing for our LPG bottles has gone up, but we have a very efficient califont, so hot water + gas hobs runs us about $70 a month. Is that high? Health I'm not too concerned, the hobs don't get used excessively and we have a Lossnay ventilating the house.

The Harrisons guy indicated that Orion would soon be increasing their export cap to 10kW per phase. What "soon" means, and how he knows this - I have no idea. But if true that would seem to be less reason for a battery?

Powerwall 3 is obviously an expensive option, so I guess my question there would be: what are you getting for the extra cost compared to other battery solutions? I know it has the inverter built in, but I'm not sure I'd view that has an advantage as if the inverter dies out of warranty you presumably need to shell out for a whole new Powerwall. So, are there other benefits?

Gas it's more future prices i'd be worried about. You can always install an electric cyclinder later.. but maybe keep it in mind for sizing the array

For me gas prices are going up 20% yoy lately and with the govt committed to building an import terminal instead of shutting down methanex, expect gas kWh prices to double in the near term as local cheap gas runs out.

HarmLessSolutions

1237 posts

Uber Geek
+1 received by user: 829

Subscriber

#3460285 10-Feb-2026 16:35

dantheperson:

Gas it's more future prices i'd be worried about. You can always install an electric cyclinder later.. but maybe keep it in mind for sizing the array

For me gas prices are going up 20% yoy lately and with the govt committed to building an import terminal instead of shutting down methanex, expect gas kWh prices to double in the near term as local cheap gas runs out.

A correction in regards to your Methanex comment. My partner's son works in the Taranaki gas sector and is up on what is happening. Maui has ceased carrying out maintenance and will shut down before EOY which will force Methanex to close down due to lack of gas supply. NZ is running out of natural gas supply fast with LNG importation being the solution of last resort at this point. This situation has been decades in the making but addressing it has been left until now by successive governments. This year will be a rough ride politically.

The LNG announcement is a bit surprising in terms of its intended implementation and funding but it will definitely have repercussions across the energy sector (both gas and electricity) so gas use going forward is probably not wise, but if the proposed "levy" (i.e. gas tax) on electricity customers blows out it may increasingly become an incentive for those with the means to double down on solar and battery investment in moving towards off grid installations.

https://www.harmlesssolutions.co.nz/

Paul1977

5171 posts

Uber Geek
+1 received by user: 2192

#3460288 10-Feb-2026 16:48

dantheperson:

Gas it's more future prices i'd be worried about. You can always install an electric cyclinder later.. but maybe keep it in mind for sizing the array

For me gas prices are going up 20% yoy lately and with the govt committed to building an import terminal instead of shutting down methanex, expect gas kWh prices to double in the near term as local cheap gas runs out.

Yeah, keeping it in mind. My thought is to generate a decent surplus to export, so should be well covered for a future water cylinder.

We paid extra for a more efficient califont, and compared to our previous gas usage in last house it has well and truly paid for itself. Ours is bottled 45KG cylinders, so no day charge and each cylinder is $141 last time I checked - they were about $90 5 years ago I think. One cylinder lasts us approx 2 months. I do enjoy not being able to run out of hot water, so I'd rather not change - but down the road it's probably inevitable.

Paul1977

5171 posts

Uber Geek
+1 received by user: 2192

#3460289 10-Feb-2026 16:58

timmmay:

We have 21 panels split between north and west facing, and a 6kw inverter... it's a little small, 7.5kw would give us a bit more generation at peak, but it's ok. 16 panels and 8kw seems like not enough panels or inverter is too large. We didn't get a battery, we pay 22c and get paid 18c, the difference is so small a battery is not worthwhile. We just sell to the grid, we had a $15 power bill last month. If we had spent thousands on a battery it may have reduced our bill to zero... not enough gain for us.

No problems with ducted heat pump + two other heat pumps being used all winter / summer.

I was guessing inverter size for the 16 panel option based on the models they have on their website as I couldn't remember exactly what he said - will know when he sends through pricing. I know the 24 panels was going to be 10kW though.

I'll do some better calculations on whether a battery makes sense; but rough estimates tell me I might not break even with the battery before it needs replacing - and if so what's the point? Also, how much better might the battery technology be in 5 or 10 years time?

I think 24 panels (12 north facing, 12 west facing), 10kW inverter and no battery will be the way forward.

What power company are you with?

kangaroo13

87 posts

Master Geek
+1 received by user: 90

#3460290 10-Feb-2026 17:04

Paul1977:

I think 24 panels (12 north facing, 12 west facing), 10kW inverter and no battery will be the way forward.

If you have roof space, you may like to consider a triple-string inverter and putting some panels on an E or NE facing roof. That will spread energy availability across the day and improve self-consumption (particularly if you don't have a battery). It's also useful to have power in the morning - winter morning heating, cooked breakfasts and to get the laundry done and have all day for it to dry!

Paul1977

5171 posts

Uber Geek
+1 received by user: 2192

#3460292 10-Feb-2026 17:17

kangaroo13:

If you have roof space, you may like to consider a triple-string inverter and putting some panels on an E or NE facing roof. That will spread energy availability across the day and improve self-consumption (particularly if you don't have a battery). It's also useful to have power in the morning - winter morning heating, cooked breakfasts and to get the laundry done and have all day for it to dry!

Winter morning heating is certainly a power draw, but it's really just a few months of the year - and is also the time of year when you get the least out of solar. Other than heating in Winter, our morning power use is negligible. So not sure whether that would pay off, but will certainly ask about it.

timmmay

20864 posts

Uber Geek
+1 received by user: 5350

Trusted

Lifetime subscriber

#3460294 10-Feb-2026 17:26

Paul1977:

I was guessing inverter size for the 16 panel option based on the models they have on their website as I couldn't remember exactly what he said - will know when he sends through pricing. I know the 24 panels was going to be 10kW though.

I'll do some better calculations on whether a battery makes sense; but rough estimates tell me I might not break even with the battery before it needs replacing - and if so what's the point? Also, how much better might the battery technology be in 5 or 10 years time?

I think 24 panels (12 north facing, 12 west facing), 10kW inverter and no battery will be the way forward.

What power company are you with?

Meridian, their solar plan is good but you have to contact them for pricing.

It's normal to overprovision panels to inverters by 1/3 - mine's more, 6kw inverter (bit more at peak) with 9kw panels. If you get say 10.5kw of panels an 8kw inverter should be plenty especially with the panels in split directions.

dantheperson

226 posts

Master Geek
+1 received by user: 63

#3460376 10-Feb-2026 22:49

timmmay:

Meridian, their solar plan is good but you have to contact them for pricing.

Solar plan pricing is online, but i had to call to sign up. Switched to them from Octopus to lock in the low user low daily connection charge for the next 3 years.

https://www.meridianenergy.co.nz/for-home/solar

timmmay

20864 posts

Uber Geek
+1 received by user: 5350

Trusted

Lifetime subscriber

#3460410 11-Feb-2026 07:19

dantheperson:

Solar plan pricing is online, but i had to call to sign up. Switched to them from Octopus to lock in the low user low daily connection charge for the next 3 years.

https://www.meridianenergy.co.nz/for-home/solar

Looks like their website had been updated. I also note that the power price for my area has gone up from $0.22/kwh to $0.285/kwh but the daily charge has dropped from $2.60 to $2.40. That unit price rise is quite large for 9 months or so. Octopus is similar. That's compared with a fixed $0.135/kwh we were on up until April last year, which was a great deal we got on some special, but power prices have basically doubled in the past year. Fortunately solar offsets a lot of that in winter, and in summer the bills are trivial.

Stu1

1896 posts

Uber Geek
+1 received by user: 491

ID Verified

Subscriber

#3460414 11-Feb-2026 07:41

in Upper Hutt we got offered by meridian $1.38 daily line charge 29.03 and import and 17c export and $300 credit we haven’t had to pay a power bill since we signed up on the 21st of August . We only have 18 panels and the same invertor as Timmy. Biggest power use is spa and 1 heat pump on cooling . We are on gas for water though

1 | ... | 119 | 120 | 121 | 122 | 123 | 124 | 125 | 126 | 127 | 128 | 129 | ... | 150