Saturday, January 14, 2012

Wood Use

Later on January 14, 2012...our second 1/4 cord stacked

January 14, 2012...the last of our first 1/4 cord

January 1, 2012...roughly an 1/8 cord

September 24, 2011...our first 1/4 cord

Its been fascinating to monitor our wood consumption this fall and winter.

By New Years Day we'd used just over an 1/8th of a cord which you can see in the middle photo above. Now, two weeks later we've used most of what was left. This means it's taken about three and half month's to go through a 1/4 of a cord to heat a 17oo sq. ft house.

Of course it has been a mild fall, so this may not be indicative of future use, but it starts to lay out a pattern for us to plan around. January and February are the coldest months of the year and it will be interesting to see how much wood these months require. It seems like a reasonable guess that we won't go through more than a cord total for the year, but we'll see when all's said and done.

(I've spent some time trying to figure out a way to present energy use in comparable terms and I'm not there yet, but I want to work it out so it can be presented in a way that would allow comparisons with other forms of fuel, house size, and energy efficiency.)

In dollar terms we paid $200/cord in July for the wood we have on hand now. Roughly this translates to about $50 to heat our home so far this heating season.

The quarter cord we are just finishing burning is a couple years old, so its delivering more btus/kwhs then the woodstack we are about to start using which has not had time to fully season. The new wood was (presumably) cut and split in the middle of the summer since we had it delivered at the end of July. After this season it will be easy for us to maintain a seasoned wood supply by having one dry cord to burn and stocking up a green cord each summer.


Kate said...

Why not use BTU/SF/YR as your calculation to compare to other houses? That's what I've been using for the past few years, I have the calculating formula to convert oil, electricity and wood to BTUs, then get the totals for the year, then divide by # of square feet. If you want to go the next step beyond that, you could use the Passive House formula which also adds a multiplier depending on the "source energy". I don't have that formula handy but could track it down since there's a PH training happening this week at YM.

dcain said...

Thanks for the tips Kate; rooting around on the web it seemed that its common to talk about energy use terms of kilowatts. Not sure where I got slowed down, but I appreciate your approach and will give it a go.

Yes, I'd love to start understanding our place in terms of passive house standards. Bill Hulstrunk did an energy analysis for the house as designed and so I know where we fall in a theoretical sense relative to PH, but the proof is in the pudding, or maybe in the woodpile that's still standing at the end of the heating season. Cheers.