Thinking of solar for 2025 after seeing the savings friends are having? RenewSolar picks out a general solar system that meets the needs of the family and your pocket. Getting Value from solar has been one of our key driving points when it comes to solar installations in the home, a cheap system may not meet all needs and value means that it is cost effective and worth while.
Selecting a solar system on budget.
Solar systems work on a few principle points, the energy you can store, and the energy you can use. While this may seem simple, its a little more complicated and here is why;
If you have a battery you need to cover your energy use with the battery, but you will also want to charge the battery. The other side of solar is the inverter, these need to cover the power use, or you will still be paying for grid power while you could have plenty stored in the battery.
Your daily use is a wrongful metric.
Many people will use a bill and then average the use per day, say 15kwh. This is not a good metric to use when selecting solar. If you think about what you use over the day (24 hours) you will use power at different rates at different times of the day. Here is a scenario which will explain it better;
You have a 15kwh battery, your day time loads are around 350w, and you have 3400w of solar panels.
Sun hours are explained here. But you need to average the power at different times of the year.
8 hours summer, 4 hours spring and autumn and 2 hours winter.
That is 27,200wh, 13,600wh , 6,800wh peak power from the solar averaged daily production.
But solar power varies all the time, something like this small system, but on a bigger scale.
Power is used at different rates though the day and night, for example 22:00 -08:00 you may have very little power use, 3.6kwh is fairly normal for that period. Between 08:00 and 10:00 you may use 2kwh, between 10:00 and 15:00 you may use 1.6kwh, and between 15:00 and 22:00 you may use 7kwh.
– 14.6kwh a day –
If your solar is making 3000w and you have a load of 300w, then your battery charge will be 2700w,
as your solar is powering you over the day, then the power at peak time (7kwh) will partly be fed from solar but also from the battery (only at certain times of the year). so between 10:00 and 15:00 we need to ensure that the night and evening power goes into the battery.
Peak power consideration for the inverter.
A inverter is sold on its power out put, a 3.6kw inverter will provide 3.6kw of power, if your load is more than 3.6kw the power is taken from the grid, when picking the inverter, you do need to meet the general load, which for most homes will be very low if you average, it is the peak loads that should be met, this is around 5kw for most homes with a family. meaning that you could be taking 1.4kwh from the grid over the peak time. – Again we account for the difference in grid and use of power required for the system.
The value metric.
To value a solar installation, the metric we use is kWh to kWh costs and savings.
if a solar installation has a value of £0.24 then it is of no value at all, because that is the grid power cost.
We use different metrics to value parts of the solar installation and then combine those to result in a ROI, which is the break even point of the solar investment.
Solar panel value metric is how many kWh the solar panels can make over the year and their cost.
8 panels £560 and will make around 7,480kWh of solar per year, or £1,795.20 per year in (potential) savings.
A 15kWh battery is around £1500, in stored power that is £3.60 per day, or £1,314 per year.
the combined annual saving is £3,109 and yet the two items costs £2,060 so we can see how this will make good value in a year. However this is not the complete system as you do have to account for the inverter as well as the mounting system and other hardware needed, as well as the installation.
The Hardware Pick
Solar panels:
425W Solar Panel — RenewSolar
Inverter:
Sunsynk 3.6ECCO hybrid inverter — RenewSolar
Battery:
15kWh Battery 48v — RenewSolar
Rails:
3.3 meters solar panel mounting rail — RenewSolar
Clamps:
Rail clamps – Panel clamps for our black rails. — RenewSolar
Hooks, cable, isolators,
The Package Comes to a total cost of just over £3,022 or the same as 12,592kWh of grid power or 2.3 years ROI for a 15kwh per day user.
But as a package, the cost may be slightly lower – Here is the listings of our Solar packages.
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