I can't find anywhere on his site what the BTUs are.
They are just to the right of the picture of one in a large wood and plastic case in the garden.
(4th picture down)
The site says:
<blockquote>"The jar candle is about 3" high and 3" in diameter and contains 4.25 oz of wax, almost 1,000 Btu's. These candles will typically burn 20-24 hours, or at about 50 Btu's an hour. This is not a lot of heat so don't be thinking you are going to heat the house with one!"</blockquote>