Recently, a few of the smoke alarm manufacturers have released wireless smoke alarms that have a 10-year battery in them, which comply with the new law and standards.
These new wireless smoke alarms require one of the alarms to be hardwired to an electrical circuit, which in a two storey home, you can usually do upstairs with no damage and then this hardwired alarm uses a base that generates a WIFI signal to all the other wireless alarm located around the house. The WIFI signal creates the interconnect between all the alarms in a home.
Please note there are only a select few wireless smoke alarms on the market that comply with the new laws, so please contact an electrician to make sure yours complies. Too many times we have had clients that bought their own thinking they complied because the box says “10 year battery.” This statement does not mean they comply.