Electric defrost/heater ?

I'm planning on rewiring and probably custom gauges to my Valiant this winter, thinking about deleting the factory heater never plan on driving in the winter but still could use a windshield defrost and maybe some heat for chilly night drives. Thinking is there some small 12v non gimmicky electric defrost/heaters probably around 500w ? Don't care if it's Diy build. Anyone done anything like that ?