I just picked up 2 Dimplex Electric Fireplaces. I live in the NW (Seattle Area) so climate here is fairly moderate. I'm only using them to heat the upstairs portion of my house approx 1000 sq ft. They seem to do an adequate job so far so I'm thinking of using them as my main source of heat this year. So my question is this, is it safe to keep them running 24/7? This is the only way it seems to keep the temp at a comfortable level.