[Greenbuilding] Heating on a half cord of wood per year.

[Corwyn]

Greetings,

It was claimed recently that a house in a cold climate (mine is 7482 
Degree-Days) would be unable to be heated on a half cord of wood per 
year.  This got me thinking, what it would take to turn my house into 
such an impossibility?

To start, my house is pretty energy efficient as it stands (details can 
be seen at my website) and used 1.5 cords last year (it was a warm 
year).  Additionally, I have a energy model for it, that currently is 
within 3% of actual fuel usage.  So, if someone were offering a free 
Nissan Leaf to anyone who could heat on only 1/2 cord of wood, what 
would I do?

Step 1: Get more heat compact firewood.  Currently, I use deadfalls, 
scrub, some hardwood, some softwood (say 20MBTU/cord) off my property. 
Since the benchmark is measured in cords (volume), I would use nice dry 
white oak at 26 MBTU/cord.  With the assumption my wood stove gets its 
rated 75% efficient, that means I need to reduce my heating needs from 
the current 30,780,000 BTUs / year to 9,640,000 BTUs / year.

Step 2: Put in a Heat Retaining Ventilator (HRV), so that I can  reduce 
my air infiltration.  The goal would be the Passivhaus maximum of 0.6 
ACH50.  This should save 7,700,000 BTUs / year.  (23,100,000 total)

Step 3: Turn the basement from a semi-heated space into an unheated 
space (includes some sealing and insulating).  Insulate the ceiling with 
12 inches of cotton batt insulation.  Saving 12,700,000 BTUs / year. 
(10,300,000 total)

Step 4: Build shutters for the wooden door, out of R-10 foam board 
(completed last summer).  Finish the triple layer interior storm for the 
french door (should be done this weekend). Savings 770,000 BTUs / year 
(9,580,000 total)

And we're done.  This would make a very cheap Nissan Leaf for me. 
Anyone willing to put up the Leaf?


Thank You Kindly,

Corwyn

-- 
Topher Belknap
Green Fret Consulting
Kermit didn't know the half of it...
http://www.greenfret.com/
topher at greenfret.com
(207) 882-7652