re: advice wanted on heating a cedar log house
14 oct 2000
>we've just rented a place out in the east kootenays (southeast bc), a
>1 story cedar log house with a 90% unfinished basement. the climate
>is pretty mild, last year frost didn't arrive until december... the
>downstairs has a wood furnace. a neighbour who lived in the house for
>9 years told us it gets very cold,
say 20 f average in december and january, with a 40 f deep ground
temp, like edmonton, suffield, summerland, and kalispell? or maybe
higher and colder.
>and that they had to once get _9_ cords of wood to heat the place.
a lot, like 1400 gallons of oil, if oak, burned at 60% efficiency.
an average us colonial farmhouse used 20 cords, without insulation.
you might look into plugging some air leaks.
>when i suggested that perhaps it might be a good idea to insulate
>the basement, he dismissed the idea, saying it wouldn't make any
>difference, as it was a case of not enough warm air getting from
>the basement to the upstairs.
that seems easier to fix than the problem of losing heat from the
warm basement air to the ground.
>there are a couple of vents that allow warm air to pass from the
>basement to the main floor, but the previous tenants put a solid door
>at the top of the stairs leading from the main floor to the basement...
i'd leave the door open. vents at different heights may work better than
floor vents since they can help the air decide on a direction (up via the
higher vent.) otherwise, the air gets confused and doesn't move well.
moving 50k btu/h of heat naturally with an 8' height and 10 f temperature
difference requires two 6'x6' holes.
you might cut a 2' square hole in the wall near the top of the stairwell
and add grainger's $35 20" 165 watt 4tm67 box fan with a thermostat to move
4550 cfm of warm air into the room with a 50k/4550 = 11 f temp difference.
>i figured the cost of insulating the basement with r40 to be around
>$350 worth of insulation + the cost of lumber and other misc materials,
>maybe $500 altogether... not a bad investment of my time (not to
>mention the strain on my back from hauling another 7 cords of wood...
people sometimes figure basements lose heat to the deep ground temp via
r10 soil. a 32x32x8' tall basement with 2048 ft^2 of uninsulated walls
would lose about 6mx30dx24h(80-40)2048/r10 = 35 million btu (2.4 cords)
at 80 f over 6 months. with r40 insulation (including the floor), it
would only lose 0.5 cords. sounds like insulation would help, especially
up near the colder ground surface, eg inside the rim joist.
removing the insulation from the basement ceiling would allow about
10fx1024ft^2/r1 = 10k btu/h to flow up into the house with a 10 f