this post was submitted on 15 Jul 2025
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DIY is the way to go. You will be able to get a dramatically larger system for the same price. I do not recommend grid tie it's not worth the rebate there's a ton of red tape and you will have to install an insane amount of extra equipment if you want to be able to actually have power during a power outage. Using an off-grid inverter with self consumption means that it's basically just a computer UPS on steroids and it also removes a ton of the installation red tape that exists for grid tie inverters.
They are actually quite simple to install correctly to code and then for extra piece of mind you can have it inspected by an electrician which is way way cheaper than having them do the installation. I decided to spend roughly $20,000 on solar and for that money I got an entire pallet of solar panels 50 of them 30 KW hours of battery and 12kWh of inverter output.
Getting the solar panels installed is a hell of a lot of manual labor that's for sure definitely one of the better workouts I've had in a while but when I compared what any solar installer in my area would give me for that price? It was a fraction of the system less than half the total solar panel output half the inverter output no batteries and most companies don't want to talk to you about a system unless it's gridtied.
Unless you are a part P registered electrician it is unlawful to connect an inverter to the consumer unit (and hence the grid) in the UK.
Also, the feed in tariffs in the UK are highly competitive.
Sure, it's possible to get the panels bought and installed and wired up as a DIY project but that's about it.
I did explicitly specify a non grid tie unit. An off-grid unit that does not do any grid feedback is literally no different than plugging a UPS in to back up your computer in terms of the impact on the grid . It will accept the grid as an input to pass through but it will never feed power back into the grid thus a lot of the red tape goes away.
Maybe it's different in the UK but for the US a self consumption off grid inverter you do not need to even inform the power company much less be any type of electrician it's only if you are doing a grid tie inverter that will put power back into the grid that suddenly there's a lot of requirements.
In the UK any new electrical circuit, which includes an EV charger, solar DC/AC inverter, cooker or lighting circuit etc is notifiable work and must be completed by a part P registered professional.
It doesn't matter if it's a self install of an inverter that can be zero rated for export, if the house consumer unit is connected to the national grid you can't self install (unless you are a registered professional as stated). Essentially to connect solar panels to a house that is also connected to the grid will always have to use a grid tied inverter.
Only way to use an off grid inverter, which is what you described, is if the house is entirely off grid (and therefore has it's own earth which is another point but not really worth going into). The description of an off grid inverter you use would not be the definition used in the UK in relation to building regs (it would be a grid tied system because it is connected to the grid, pass through is irrelevant).
Oh, well that's stupid and overreaching regulation. I can only imagine what the services cost when it's forced like that probably worse than around here. Imagine not being able to install a new light circuit because you aren't a certified electrician that's nuts lol.