Winters here in California can get very cold which is why I have been using a combination of electric and gas heating. I did a bunch of research on the Internet and came to the conclusion that the Mr. Heater brand MH18-B Big Buddy propane heater that has three settings for 4000 BTU, 9000 BTU, and 18,000 BTU would be the best heater for my purposes.
The MH18-B Big Buddy propane heater goes for around $180 on the Internet. I didn't want to spend $180 so I looked around for a refurbished unit from the manufacturer. Lucky for me they had the exact heater for around $85.00 but they wouldn't ship it to me in California.
I got a hold of a friend of mine who has a buddy who lives in Oregon. His buddy agreed to have the company ship the heater to him, and then he would ship it to me. The shipping fiasco took about three weeks but in the end I only paid $115 for a perfectly good working unit from the manufacturer with a full length warranty. Here are some pictures of my brand new refurbished Mr. Heater brand MH18-B Big Buddy propane heater.
These types of heaters are considered to be ventless. California has a law in place that forbids companies to ship ventless heaters to residents because no heater is really ventless. There are severe safety issues regarding these types of heaters and their use. I rarely use mine on the 9000 or 18,000 BTU settings.
I never leave the heater on while I sleep. The safety features built in are fantastic but I went ahead and bought a battery operated carbon monoxide sensor as an additional safety precaution. These types of heaters burn propane but they also consume the oxygen in the room which can lead to insufficient air to breathe. I also use an electric ceramic heater and I alternate the use of both.