There are two different things here to think about: power (kW), and energy, which is the running sum of power delivered over an amount of time (kWh).
If you look at your electric meter, it'll tell you how much power (kW) your home is consuming at that point in time. There's also a kWh counter which shows how much energy you've used since the meter was installed. Typically your home might be consuming 1-5 kW of power at any point in time, depending on if an oven is preheating, EV charging, AC or heat pump running, etc. The Air will be able to supply a maximum of 19kW of power back to your home. This should be plenty of power for most homes.
The second part is how long the Air could supply power to your home. The Air has a battery energy capacity of about 110 kWh. If your home uses say 220kWh of energy per month, then the Air could power your home for half a month, if it started fully charged (100%) and you operated your home with it until it was fully depleted to 0%.