Thanks to a marvelous landscape designer we have a gorgeous back yard with a wonderful deck and pergola. The challenge is that living in Vancouver, BC we get a lot of cooler nights where a heater would let us enjoy it more.

I've done some research and have the following questions :

1) Any comments on the pros/cons of natural gas vs electric? We have natural gas and electrical outlets out there already

2) Any rules of thumb on the BTU's or wattage required for heating a given area? It seems 40,000 BTU is typically rated at 20' diameter, and 1 manufacturer said their 1600w electric would heat a 10' x 10' area but I'm not confident of either rating

3) Any brands particularly good or bad? Keeping in mind here in Canada we have a more limited selection

4) Any comments on whether it's worth it to go higher end? The "typical" consumer grade stand alone 40,000 BTU natural gas heater seems to be about $400 Cdn, and the same grade of electrical seems to be about $250 Cdn - the next level up increases those prices by about 75-90%, adding extended warranties and higher output

Thanks for any assistance. I thought this would be easy ...

- R.