While demolishing, a reciprocating saw can be useful since it can cut most materials. The saw has a voltage of 18 volts and isn't all too heavy at 1.7 kg.
From Amazon
Metabo - 18V Compact Reciprocating Saw Bare (602266890 18 LTX Compact Bare), Woodworking
Acme Tools
Metabo Compact Cordless Reciprocating Saw (Bare Tool)