Wood Heat

On Tuesday I built a small break-in fire in my wood stove.  According to the user's manual, this must be done when the stove is first fired, and again each season as the stove is readied for use.  Then early yesterday afternoon a strong storm system moved in, bringing heavy rain, high winds, and temperatures in the mid-40s.  Burr!  With the propane-powered heating system cycling on, I decided it was time to give wood heat a try.

As I've often noted, this is a partially passive solar structure.  During the design phase Bob, my architect, recommended building a masonry wall in the living room to serve as a thermal mass.  This "Great Wall of Presque Isle" — concrete block filled top-to-bottom with concrete — would absorb solar heat when the winter sun played on it, hold that heat for a time, and then slowly release it during the evening hours.  (Over the past few days, as the sun has tracked lower in the sky, sunlight has begun shining directly on the wall.  In the first photo below, note how deeply the afternoon sun penetrates the building on the day after the winter solstice.)

12/22/10 — Foam insulation on the exterior
dining room walls.  Pink fiberglass
surrounds the half-bath.

12/22/10 — Most exterior walls have
six inches of foam, as here in the stairwell.

In addition, Bob said, the wall would pick up radiant energy from the wood stove, releasing it along with its solar load.  In this manner the wall would balance temperatures in the house by avoiding the quick up-and-down swings which many homes experience as the heating system cycles.

This balancing act is enhanced by the tight envelope, particularly the high levels of insulation in walls and ceilings.  Kyle, my primary contractor, noted that the insulation here exceeds what he had seen in most Michigan houses.  But this is the "new normal."  If we Americans are serious about energy conservation, and intend to use fossil fuel by the teaspoon rather than the bucket, this is how new houses will be built in the future, and how existing homes will be retrofitted.

Note, too, that we used structural insulated sheathing on the exterior (between the studs and siding), rather than the conventional plywood sheathing.  A 1-inch SIS panel adds R-5.5 to the overall R-value of the exterior wall.  I believe this gives me at least R-35 walls and roughly R-50 above the ceilings.

The stove is finally alight!

I chose the "Heritage" wood stove, made by Hearthstone, because it uses soapstone for the unit's walls.  Like the masonry wall, soapstone warms up as the stove is fired and slowly releases its heat over a period of hours.

Based on just one day of use, the system appears to be working according to spec.  When I turned in last night about 10:30, having fed the stove its last couple logs, the temperature upstairs and down was 70 degrees.  At 7:30 this morning it was 68, a loss of just two degrees over a nine hour period!  Indeed, my stove was still slightly warm to the touch.  Meanwhile, the storm had blustered through the night, with rain driven by winds of 30 mph and higher.

The only downside is that the stove is out-gassing volatiles used in manufacture.  I tried to ventilate the house as best I could, but the storm made that difficult.  I ended up with a headache.  God willing, that process has run its course.

Now I have to figure out how to empty the ash pan below the firebox.  Time to read the user's manual again!  And I have to find a better way to protect my firewood supply.  The storm has blown aside the plastic tarps and now the wood is wet. •••