The cost of installing solar panels has recently reduced, while electricity costs have increased. For many homes in Ngaio, investing in solar can be a smart financial investment. It may pay for itself in 4 years and provide free power for the following 20 years.
Several members of the Ngaio Climate Crew have installed solar systems and are happy to share how they did it, what it cost, and what they save. You can explore summaries of their solar systems by clicking on the tiles below.
Want more information?, call Ross on 021 404089, email [email protected] , or keep an eye out for our next event.
18 panels; 7.3 kWh battery
18 panels; 6kW Inverter; 10kWh battery
12 panels for 3Kw capacity
8.80 kW Panels;
20kWh Battery
Hewett Way Bidmeads
- PV Capacity – 18 x 405W panels for 7.3kw nominal capacity.
- System Type We chose a hybrid system, expecting a slightly lower return than panels only, but wanting resilience from power cuts.
- The inverter is only 5kW, so it can’t convert the last bits of the panels’ electricity to AC power at midday in summer. But we don’t need the power then, and it’s efficient in winter.
- Battery capacity 7.3 kWh (6.5 usable).
- Cost The quote was for $22,000 installed. A meter change to support exporting power to the grid was a further $160. There were no additional fees from the installer.
- Savings The installer correctly estimated the electricity that would be generated on a monthly basis. So far, we have 1% difference between actual and estimated. We generate about 9,000 kWh a year.
- The installers’ estimates of usage, costs and buyback prices were not accurate. However, we will have a net-negative electricity bill for the current 12 months. We are also planning to replace our gas hot water, which will increase our power savings to well beyond the estimated $2,400 p.a.
- The installer’s quote estimated an IRR of 13.53% and a payback time of 8 years 1 month. Based on the current performance, we will do better than that.
- Installer Solar Worx – We would use them again.
- Electrification state. Before and after PV install:
- We were a low-volume user of electricity with instant gas hot water and limited use of gas home heating. A wood burner is our main source of winter heating.
- We have a PHEV (plug-in hybrid car) that we charge on a standard 3-pin plug in the garage.
- Having seen the savings and power generation from our solar system, we are replacing our gas systems with electrical ones.
We currently use Electric Kiwi as our electricity retailer. We recharge our batteries at 6 am in winter, using our free hour of power to ensure we have free power through the morning.
Aplin Terrace
We installed our PV system in 2022. W started researching late 2021, settled on a supplier and the install was scheduled for March. Once completed, we then had to wait about 4 weeks until the installation was signed off by an independent certifier.
We wanted a PV system that could continue to operate in the event of a grid outage so that we could also provide basic power for ourselves, and neighbours. (Not all PV systems have this capability). This also meant that we had to identify the essential circuits to be linked in to the uninterrupted power supply (UPS). For us this was fridge/freezer, oven, lighting, and a few key power circuits to router etc.
- PV Capacity – 18 Trina Vertex 385W panels for 6.9Kw nominal capacity. We have 6 North-facing and 12 West-facing panels
- System Type We have a hybrid system, with a 6kW Inverter and a 10kWh battery
- Cost. We were initially quoted for 16 panels, but while the crew were installing, we saw there was room for an extra 2 panels, so added them at the time. After 3 months there was a problem with the initially installed inverter and battery, the system was down for two months before an upgraded inverter and battery were installed. Our providers, Lightforce, were generous in compensating us for the disruption. This system has been running well for nearly 3 years since September 2022. The final cost for our installed system was $31,600. Our installers, Lightforce, reimbursed the cost of upgrading our meter to an import/export meter. Lightforce also covered the cost of the inspection to sign off and commission the system so it could go live.
- Production info since September 2022:
- Our baseline annual grid consumption prior to going solar was around 6.2MWh. In the time our PV system has been running, our annual power consumption has remained largely unchanged, while our annual grid consumption has reduced by 80% to around 1.3MWh.
- Annual generation has averaged 8MWh,
- Exported power to the grid has averaged 3.2MWh
- Electrification state. We have a conventional electric hot water cylinder, electric ovens, a pellet burner heater, and currently have bottled gas hobs. We purchased an EV in 2023 which we now largely charge at home using trickle charge. We will probably replace our gas hobs with an induction hob
- Current Electricity Retailer. After purchasing our EV in 2023, we signed up with Meridian’s EV plan which offered a $300 credit on a 24 month plan, a night rate of 16.7 c/unit, and solar buyback @ 12c/unit. We’ll probably review this when the current plan expires and see what else is on offer
- I’ve been looking at our total energy spend across bottled gas, wood pellets, electricity, and petrol. After installing PV, the annual average total cost has gone down from $3,900 to $2,200.
- We’re both retired and are home during the day
- Solar Supplier – We contacted three suppliers, got quotes from two, and went with Lightforce. One of the main reasons for going with them was that they do their own installation and support so that we’re not having to deal with different parties. We’ve found them very responsive when issues have arisen.
What would you do differently? If we were a family, we might add East-facing panels to start generating earlier in the day, and possibly a few more West/SW panels to continue generating longer in the evenings.
Hewett Way
We installed our PV system in 2014.
PV Capacity: 12 Canadian Solar CS6P 250W panels for 3Kw capacity.
System Type: Grid-tied (no battery)
Cost: We were initially quoted $9995 fully installed, however, we opted for a different inverter to the one that was quoted, and paid a total of $10,995. The upgraded inverter was able to give us reporting on generation, which was important to us.
Installer: The installer was Righthouse, which is no longer trading.
Savings: We initially calculated that the system would pay itself back in 15 years, based on our usage and electricity rates at the time. Several factors have affected this over the last 11 years.
– 6 months after our install, Meridian (at the time the best option for solar buy-back) cut their buyback rate from 25c/kwh to 7c/kwh.
– lines charges have increased dramatically (the daily charge for the privilege of being connected to the grid, irrespective of usage).
– our family size has increased, with a corresponding increase in daily usage
– power prices have increased much faster than anticipated
For the first few years we tracked our generation and usage diligently, however it is now very much back of mind. We no longer obsess over the minutiae but have peace of mind knowing that the PV system is quietly saving us money everyday. It is likely that the system has already paid for itself.
Electrification state: We use conventional electric hot water, and primary heating is from a wood burner and heatpump. Prior to the PV install the heatpump was used in winter only. Now we will often use it guilt free for cooling on hot summer days. We purchased an EV in 2022.
Chelmsford St
- Objectives
- Reduce long term home energy costs and improve environmental and economic resilience.
PV Capacity
- 20 panels (10x facing north-east, 10x facing south-west). Total 8.80 kWp.
- Actual generation is about 7.5 MWh/year.
- In 2026, about to add 2 additional panels to maximise potential generation with existing inverter.
Type of System
- Hybrid – 5kw Inverter
Backup capability
- If the grid fails, the system will continue to operate backup circuits for lights, kitchen appliances and internet.
Solar Supplier / Installer
- Front-End Solar. We would use them again.
Cost
- ~$45k – as part of a major renovation that included replacing end-of-life gas and wood fuelled systems with electric heat pumps for space and water heating and a new switchboard.
Savings
- Previous total household energy usage (demand) was ~20 MWh/year. Current usage is a bit less than 10 MWh/year.
- Reduced demand by installing more efficient systems and improving home insulation (including double glazing).
- About 65% of the remaining energy consumption is self-generated.
- Overall first year reduction in energy bills was approximately $3,500.
- Further savings are now being achieved by:
- moving to a time of use plan. ~80% of the grid power we still use we buy at night-time rates and use battery to store. This will save ~$500/year.
- replacing petrol vehicle with a battery only EV will reduce fuel costs by ~$1,500 / year by charging from excess solar and at night-time electricity rates
Electrification State
Previously used electricity, gas (space and water heating) and wood (space heating).
Now all-electric..
Have also replaced petrol vehicle with battery EV.
Current Electricity Retailer
- Recently moved to Toast Electric (part of Wellington Sustainability Trust).
House Usage
- We are generally home during the day.
What would you do differently?
Might have done more research, might have installed a larger capacity inverter. However, very satisfied with what we have.