I've been considering getting an sdr, I think you've just pushed me over the edge - thanks! The dream however would be per outlet (or circuit) monitoring. Setting up alerts if wife leaves the hair straightener plugged in, fan left on, etc.
You can get them in allicdata https://www.allicdata.com/products.html
There are some little tools that make this easy: https://github.com/bemasher/rtlamr
You'll need to do a little detective work to separate yours out from the neighbors' but it's not hard.
For my house, I can also read water usage and natural gas the same way by alternating through the relevant frequencies.