How to Choose a Solar Inverter 2021

How to Choose a Solar Inverter 2021

How to Choose a Solar Inverter 2021

After the panels the solar inverter is the next most important part of a solar system. its job is to convert the DC electricity produced by your solar panels into AC electricity used by your home. there are dozens of inverter brands available in the market how should you know which ones are good and which ones are lemons. that’s where I come in with 11 years of experience in the solar industry. I’ve put together this chart on the left are the cheaper inverters on the right the more expensive inverters but whether they are budget or premium if the brands are on this chart I’d be happy to have them on my home.

What you might not realize is that some parts will stop working in the first 10 to 15 years is the inverter as it operates 24/7 and power electronics can only do that for so long. I’d expect a premium inverter brand like Fronius to last a few more years than a budget inverter brand like goodwill. The reason behind it is the architecture so for that reason if you have less money. I would advise buying a premium inverter with budget panels instead of premium panels with a budget inverter.

Warranty

Now let’s talk about warranties. the minimum warranty offered by all the major inverter brands is 5 years but many brands now offer 10. 10-year warranties as standard such as goodwill and sunglow. this gives you a lot of bargaining power. if your installer is trying to sell you an inverter that doesn’t have a 10-year warranty you might even be able to get them to throw in the 10-year warranty upgrade for free just don’t tell them. I insist on a 10-year warranty with your inverter.

Technologies

Now let’s talk about inverter technologies. inverters come in two main varieties. one is string inverters which are a big box that goes on the wall which all the solar panels connect into and teeny tiny micro inverters that go on the back of each solar panel. there are lots of string inverter brands that I’d be happy to have on my own home but when it comes to microinverters.

Micro Inverters 

The only game in town as far as I’m concerned is a brand called enphase. now, why would you go for micro inverters over a string inverter well they provide several advantages. they optimize each panel individually with a standard string inverter like a Fronius. if one panel gets shaded it can cause all of the panels on that string to drop in performance kind of like when you stand on a hose when you use micro inverters each panel is independent of one another so if one panel is shaded only that panel will drop in performance and all the rest will come along nicely.

Another benefit of micro-inverters is that they convert the DC power produced by the panels into AC electricity at the source at the panel. so you don’t need to run high voltage DC cables through your roof while stressing that well-installed solar is perfectly safe whether DC or AC.

This is why I chose microinverters for my own house. my house is made of straw seriously and I didn’t want high voltage DCdc running through the straw. the other nice thing about micro-inverters is that you can monitor each panel’s performance. To be honest 95% of people that get a microinverter system get bored of this checking after about a week but if you’re really into your numbers it might be worth it for you.

The disadvantage of micro-inverters is that they are expensive they’ll add about 20 to 25 to the cost of your solar system compared to using a string inverter. 

Optimizer-based string system

Another option similar to micro inverters is an optimizer-based string system. At the time of filming the two brands that offer the first party, optimization is Huawei and solar edge with tango optimizers as an inverter agnostic option.

An optimizer-based system has the string inverter on your wall as well as small boxes of electronics called optimizers on the back of each panel. they offer similar benefits to micro inverters despite being a different technology optimizer-based systems are slightly cheaper than micro inverter-based ones but generally, it works out about the same about a 20 price premium over a standard string inverter without optimization.

A quick note to houses that have three-phase power if you have three-phase power to your home. I recommend using a three-phase inverter you can use a single-phase inverter but you are more likely to have over-voltage issues. if you push all your solar exports down a single wire instead of three so I’m a big fan of three-phase inverters. for three-phase homes solar inverters and oversizing, I get emails all the time saying I’ve got a quote for solar they’ve offered me a 5-kilowatt inverter and 6.6 kilowatts of panels an inverter is rated for is known as inverter oversizing and it’s a really smart design move for a few reasons.

Solar Rebate

Firstly the solar rebate is based on panel capacity how many panels you’ve got not inverter capacity. you can have 33 more panels than an inverter is rated for and still claim the rebate and since there’s little extra installation cost involved in adding 33 more panels when the installers are already on your roof oversizing really delivers bang for the buck.

Secondly, you’ll squeeze way more power annually out of an oversized 6.6 when compared to five kilowatts of panels. so many people want to buy a battery-ready solar system that they can add batteries to once they’ve come down in price a bit. the bottom line is when you use a method known as AC coupling. you can retrofit batteries to any existing solar system regardless of what inverter you have

For example, I had a tesla powerwall retrofitted to my existing six-kilowatt three-phase micro-inverter system with no problems at all. some installers might try to push you towards getting a hybrid inverter as a true battery ready option but unless you’re planning on adding batteries soon they’re not worth the extra expense over a non-hybrid inverter that you can AC couple a battery to the exception here is if your local network has a silly rule preventing you from adding an AC coupled battery.

Consumption Monitor

Consumption Monitor

I won’t go into the details of that here but a good local installer will be able to navigate that situation to finish off. I want to talk about the importance of having a consumption monitor with your solar system. a consumption monitor is a small box that sits inside your switchboard it measures how much electricity is coming from or going to the grid to be clear you absolutely can install a solar system without a consumption monitor and it will work but I strongly recommend getting one without a consumption monitor.

Although your inverter will be able to tell you how much solar is being generated at any point in time you’ll be blind as to how much solar is being used by your house. I could make a whole other video on why you should have this information but for now, just let me say that for around 500 bucks a consumption monitor will allow you to understand exactly how your solar system is working and the best way to manage your energy for maximum savings. for me, it’s worth every dollar to summarize the solar inverter is the workhorse of your solar system.

Conclusion

Make sure you choose a reputable brand that will go the distance my recommended brand chart that I showed earlier can help you here aim for a 10-year warranty with your inverter even if you have to pay a little bit extra. consider micro-inverters or optimizers if you have shading issues on your roof or if you like the sound of being able to monitor those panels individually don’t be afraid of oversizing your system by 33. it’ll deliver great bang for the buck and provide extra generation in those cold less sunny winter months insist on consumption monitoring with your system.

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