I'm considering an eHERMS HLT for 5 gallon set up. I live in an old house with oudated electricity, so I'd like to put as little demand on the electric system as possible. I'm considering using a propane burner to get my HLT in the neighborhood of my desired temp and then kick on the heating element to maintain that temp. If I operate like that, can I get away with one of the 120V, 1500 to 2000W elements to maintain temps and maybe get it to heat up water 10-20 degrees if I wanted to do a step mash? In other words, could I get away will a less powerful element if I use a burner to do the lion's share of the work?