As posted on January 21, 2009, we’ve been using bear bricks as our preferred wood fuel since that same day. Since that date we’ve consumed 61 trays of bricks (12 two-pound bricks per tray). In 49 days we have used 732 total bricks, or approximately 1.24 trays (apx. 15 bricks) per day.

As stated in an earlier post, we burn our catalytic wood stove for probably 8 to 10 hours per day, seven days per week. Overall we’ve kept the furnace thermostat turned down to a very conservative level. We typically set the thermostat at 57 degrees when we go to bed, and it rarely cycles at this level. In the morning, we raise the thermostat to about 65 degrees and run the furnace usually through mid-morning.

Over the past month, we’ve been relying less on the stove –mostly due to convenience;  subsequently we’ve used the furnace more. Back on December 30, 2008, I reported that the gauge on our B99 biodiesel tank (275 gallon capacity) was sitting just below the 7/8 marker (apx. 215 gallons of recycled veggie oil fuel). As of today, the gauge is sitting just slightly above the half-tank marker (137.5 gallons remaining). Since December 30, we’ve consumed close to 77 gallons of biodiesel to heat our home. That’s a mere 1.13 gallons of fuel per day.

As reported back in December, it has been 43 weeks since we filled our biodiesel tank with 201.7 gallons of B99.9 at the astronomical rate of $4.38/gallon ($883). The remaining 74.3 gallons in the tank came from a refill on January 28, 2008, at the cost of $3.65/gallon ($271). Therefore the average cost of the fuel in our tank is $4.20 per gallon. Using the figure of 1.13 gallons of fuel used per day, that puts our daily biodiesel fuel cost (since December 30, 2008) at $4.75. Today’s rates are about $1 less per gallon, which would bring daily cost down to $3.62. Of course we purchase our fuel well in advance of its use, just like the large utilities, so we’re not paying today’s rate (unfortunately).

If you look at our B99 heating fuel consumption since our last refill, you’ll see that we burned an average of .46 gallons per day since may 12, 2008. That’s aproximately $1.93 per day at the price of $4.20 per gallon.

So what does all this mean? Simply enough, I believe we’ll be able to make it through this winter with the B99 biodiesel we have in our tank right now –which is fantastic news. Ideally, I don’t want to refill the tank until we’ve dipped below 200 gallons (as we receive a discount for greater quantities), but I also need to be cognizant of the daily cost of fuel, which rises as summer approaches. I’ll balance these competing variables as best as possible.

In summary, we’re finding an interesting balance in our heating needs and fuel sources as the year goes on. Looking at the figures in this post, I see that we’ve spent approximately $3.83 per day for bear bricks, and $4.75 for biodiesel. This puts our daily, winter-use fuel cost at $8.58. Subsequently, our monthly fuel cost has been approximately $257 during the winter months. This is unfortunately about $1 more (per day, $30 per month) than it would be at today’s biodiesel cost.

The bear bricks are great for space heating –front of house– so they provide an excellent means to help us heat our home in the evening as we keep relatively close to the front of our home as the night wears on. During the day we use more of our home’s total square footage, so it makes sense that we use the furnace during these hours.

Looking at the figures above –and based on today’s B99 costs– the cost of biodiesel and bear bricks for a day’s worth of heat would be nearly identical. As both fuels begin to dwindle, this begs the question as to whether we should invest more in bear bricks or B99 biodiesel. Both fuels are locally produced in Oregon and produced from waste by-products, so the environmental benefits are similar. Regardless, at the end of the day, I’d have to lean towards the B99 as it’s simply easier to use the thermostat than manage the wood stove (which is relatively easy as well). This being said, the wood-fired, cast iron heat is excellent in the evening when you just want to relax.

Whatever we decide, I think we’ll be able to continue finding the right balance as winter comes to a close (hopefully very soon). Here’s to sunnier days ahead.