On 2/2/2011 7:07 PM, Jim Franklin wrote:
> Since my tools are rusty enough, I'm thinking of using electric heaters in the
> garage. Can someone confirm my math here?
Sounds like you've already got a good handle on it. But you might have
a look at this document, starting around page 9:
http://geoheat.oit.edu/ghp/survival.pdf
It calculates the cost of producing a mega-BTU of heat from various
sources. Sounds like kerosene is similar to fuel oil in energy content.
For any combustion source, there is a fixed maximum chemical heat
yield. Subtract for combustion inefficiency (ie: not quite stoich') and
heat lost through the chimney or vent and you have a rough idea what it
costs.
For electricity, a given KWH is exactly 3413 BTU. It's usually 100%
efficient, since all the heat goes into the mass you're attempting to heat.
So when I got ticked off at the cost of propane for water heating, I
used the local $2.37/gal for propane and $0.080/KWh for electricity.
Electric comes out to $23.57. Propane, using 82% efficiency = 32.81.
Propane would have to be <= $1.74/gal to break even with electric. The
propane guys also want an annual tank rental fee and bogus surcharges.
Have to figure all that in too to be 100%
HTH,
-Wayne
|