Thank you. I should have mentioned in my question I was referring to oil filled space heaters. Sorry bout that.
While shopping oil filled space heaters I noticed they have two heating methods. Radiant and combustion. Radiant apparently doesn't blow the heat around the room, it just creates the heat while the air in the room circulates it. Combustion oil heaters actually have a fan to spread the heat.
I've been doing a little homework trying to decide if one is better than the other. I'm thinking in a small room (about 13x13) either would work fine. But thought I'd ask around as well.
Thanks all!