I have kept accurate records of my propane deliveries for my workshop so that I can track the efficiency of my heating system.  Below is an annotated chart showing propane use, cost and notes.  I am rather pleased to see that I am continuing to reduce my fossil fuel consumption as I learn to optimize my heating systems.

The building is abut 1260 square feet and the propane is used to automatically augment the solar heating system.  As the heat output from the 80 gallon storage tank drops below 140F a Bosch Aquastar propane heat on demand unit ramps up it's flame to maintain 140F to the radiant slab and 2nd floor baseboard radiators.  The design goal for the solar heating system is that it can heat the building down to 32F on sunny days and below that I use propane and the wood stove.

I plan to burn more wood this year to reduce costs -- both scrap from my workshop and standing dead wood that I harvest from our property with my cordless 18 Volt chain saw.  In the winter of 09/10 I burned 20 feet of old cedar fencing that a friend asked me to remove for her, that stuff burned hot!  By burning wood in a clean burning wood stove I am just shortening the carbon cycle of the wood that would naturally decay and release carbon eventually.  So this is basically carbon neutral.

SEASON	GALLONS	$/GAL.	$/SEASON	NOTES
2009/10	267.5	$1.89	$534.82	Warmer year, and burned a lot of free firewood
2008/09	301.7	$2.76	$832.69	Colder winter, and definitely burned more firewood due to propane price surge of .84 cents/gallon.
2007/08	409.57	$1.92	$786.38	Warmer winter, but probably burned more wood this season
2006/07	441.5	$1.99	$878.58	Propane price jumped 50 cents!
2005/06	412.9	$1.49	$615.22	installed wood stove and saved 147 gallons!
2004/05	559.9	$1.41	$789.45
2003/04	658.5	$1.29	$849.46	A cold winter
2002/03	691.25	$1.24	$857.16	Added 2 more collectors + bulk buy on propane
2001/02	771.52	$1.29	$995.27	Californian adapting to Maine and setting the heat high!