Affordable home alarm

[Nix]

I'm a security systems engineer by trade so anyone interested in burglar alarms or cctv I'll be happy to advise.

Re SHTF scenario, the grid would most likely go down, the burglar alarm main battery back up would last a few hours depending on how healthy the battery is (should theoretically last 8 hours with one activation) and then you're left with the bell box back up battery which should time out in 15 - 20 mins. That's it, one dead alarm system unless you have a power back up eg solar/wind -> battery bank -> inverter. With cctv and a DVR there's no back up battery built in so, again, if you have your own power supply, you're snookered.

Re wireless, I'd advise against it, they have a history of being problematic.