A microinverter inside the kit ties itself to the grid and pushes its output back through an ordinary wall jack, where the house eats it before it draws anything through the meter [3]. Thomas Ricker, writing at The Verge, describes plugging a cable carrying 800W into a standard outlet, watching nothing spark, and seeing that sunny day's electricity bill fall to nearly zero [15]. None of that is visible to a utility, which is why the legislative work went into the hardware rather than the paperwork.
The pitch is a supermarket purchase starting around $300 [2] against roughly $15,000 for a contractor-installed, permitted rooftop array [1], a factor of fifty [4]. What Ricker actually operates is a 400W set of panels plugged into an $1,800 power station [10][11]. The panels have behaved exactly as advertised: 709kWh over 21 months, about EUR 225 saved, close to the price of the kit [10]. That is roughly 34kWh a month [1] at an avoided rate near 32 euro cents per kWh [2]. The rate is doing most of the work in that payback, and the column gives no US residential rate, so the American version of this arithmetic is unknown. Tariffs on panels and batteries plus the loss of the solar tax credits put US buyers above the European costs the payback came from [13].
The battery is a different purchase in the same box. At the savings rate Ricker reports, about $12 a month, the $1,800 power station needs something like 145 months, or roughly twelve years, to cover itself on bill reduction alone [3]. He does not justify it that way. He values it as blackout power for a fridge and as the thing that lets him live and work off grid for months as a vanlifer [11][4]. Smaller units start around $500 for 1kWh and $1,500 for 3kWh [4].
The regulatory ceiling in the US is actually more generous than Europe's. European systems can feed up to 800W into the home, while US states typically allow up to 1200W, half again as much [12][6], with more panel capacity permitted when the surplus is diverted into storage [12]. Demand evidence, though, is all European: of the 27 EU member states, only Sweden and Hungary still prohibit these devices [14].
So price the two halves separately and make each stand on its own reason. Test one is arithmetic: at your retail rate and your wall's orientation, does a kit starting near $300 clear its own cost inside two or three years, the way a 400W set did at 32 euro cents per kWh [2]. Test two has nothing to do with the meter: whether you would pay $500 to $1,500 for a battery that saved you nothing, for the freezer in an outage or the campsite in August [4]. If both pass, buy both. If only the first passes, buy panels and leave storage for later; if only the second, buy the battery on its own merits and skip the grid-tie question entirely. The failure mode is letting the panel payback launder the battery decision, which is how a $300 appliance becomes a $2,100 one.
