My electrician buddy was admiring my new Honeywell LineVolt Pro 8000 (TL8230A1003) as we prepared to install it. This is a DPST model (two red/two black). I told him I would like to find similar models for my SPST units (One red & one black wire) for my smaller rooms. He said that since I got the thermostat at a great price, I should just do all the rooms with the same DPST model. He said I should simply pigtail both reds and both blacks (Line & Load) and then tie into the existing wiring. I told him this either could NOT be done or it would shorten the life span of the stat. He says I am an idiot. We have a pitcher & pizza riding on it.