Relay to turn on an inverter?

Not really arduino related. I have been wanting a way to turn on an emergency circuit in the event of a power outage. I would like a few strings of LED Christmas lights to turn on to illuminate the house. Please advise if this sounds like it would work (and is the easiest/cheapest way).

I am thinking 120v relay, either NC or SPDT that is in line to an inverter switched on with the appropriate loads plugged in. Line voltage would OPEN the relay making the inverter not have power. Upon power outage, the contacts would close, thus powering the inverter.

Concerns: Surge current welding the contacts, though since they'd be welded CLOSED it should be easy to notice. I am an electronics noob. My thought was a capacitor in series with the inverter power lines. I was thinking that may take the surge out letting the contacts close before the power is applied. Not sure if that is how it works, or if it is feasible. I'm thinking max starting load would be around 10A or so.

There are inverters that have instant transfer switches built in, but they are multi-hundred dollar affairs for off-grid applications, not quite ready to go there (yet... though a large UPS sounds great). So, am I on the right track?

I once did the same trick, keeping the relay energized in event of lack of power, the normally closed/open whichever springs to life...

But, the relay consumes power 24/7, also this inverter is powered how? 12v battery? In which case you don't really need an inverter unless you really like Christmas lights..

Use two relays, the first connecting the inverter to power thru a precharge-resistor (a few ohms) - once the caps in the inverter has charged, the main relay can kick in.

// Per.