Hey everyone out there, I am somewhat new to Victron. We recently setup a system in a RV conversion I did so I am not 100% new to it. I have been really happy with the products I have and have been using for the last year. We are currently building a house and I would like to setup some pv to offset the use on the grid as our local electric coop is a monopoly and their prices per kw seem to be all over the place. My main question is how many of you here have a grid tied or some sort of system where you have grid power but also are running some percentage of power to your house through Victron equipment? If I could I would really like to use an easy solar gx or Muti rs solar but seeing as they are not ul certified I will probably end up using a multi plus or quatro. Our house will be small and not need a whole lot of power but I am planning on running a 24000 btu mini split, and I will need a 240 v power connection for our water pump. These would be the only 240v items that I would have. My initial plan is to run a slightly underpowered system on a portion of my outlets. These would be the essential items that would continue to operate in the event of a long power outage. But after some conversation I am wondering if everything should go through the system. If I wanted to start off with just one inverter. Could I use an auto transformer to step up the power to 240v for the ac and water pump? Or would it be more ideal to step down to 120 for the whole house? What setups are other people using? I am tossing around the idea of an eg4 mini split that can run on its own independent pv array to eliminate the major draw but that has the drawback of it only being a single unit vs 3 9k inside units to one outside unit.
Welcome!
Going with Victron in the US for permitted house installations is not a smooth process.
You will definitely need one of the UL 1741 listed models at a minimum.
In some states like California, you can only do full off-grid, as the power companies have an approved list of inverters that support UL 1741SA and SB, which Victron does not support.
Furthermore, ESS on Victron in the US can be very difficult to get approval from the Power Company, depending on their interconnection agreement. Even if you do not intend to sell back power, you will still need an interconnection agreement and smart utility meter.
Ok, that’s a rough sketch of the administrative side. On the technical front, you will want a two-inverter split-phase configuration at a minimum. If you want to power the HVACs, you will be looking at significantly more wattage and costs.
Autotransformers are generally more complex to deal with. If you only have a single 240v load like a pump, then they make lots of sense. The Victron autotransformer is limited to 28A continuous neutral current. In a 120->240V step up, you are limited to 14A@240V.
This is with ESS as I mentioned above.
Come on Victron, show us some love here in the States. UL1741SB and a MID (microgrid interconnect device) would make me very happy. 
Thanks Rick for the info. I was really hoping to avoid having to setup two inverters for cost and space availability. This is where I was considering An eg4 mini split as I could set that up independently from the solar side of things, if this is the case then I could use an auto transformer to run the water pump. It all may be too cost prohibitive in the long run.