I've got a portable Calor Gas heater in the front room that gets wheeled into the kitchen/diner where my desk is when it's needed. I open a window when I use it but the sight of those loving orange heater elements warms you instantly, I run it for about an hour & it heats the whole ground floor up. I'm in a small terraced house though so the heat is easy to contain. Upstairs is heated separately. I don't like much heat myself so firing up the calor gas fire for an hour suits me, I live alone so there's nobody opening doors coming in & out. Nice convenient instant heat & at a good price if you ask me.