Hi Chris,

As promised, I've built a spreadsheet model using Ottawa's 2007
weather data to estimate the potential energy savings of a Fujitsu
12RLQ ductless heat pump (I'm hoping 2007 is typical of most winters).
This particular unit has a nominal rating of 12,000 BTUs/hr cooling
and 16,000 BTUs/hr heating, so it's a little undersized for your home
and local climate. For our purposes, I've assumed the low temperature
cut-off point is, in fact, -15C as stated in the technical
documentation and not -20C as I've been told antidotally. I've also
assumed your heating season begins October 1st and ends April 30th; if
it extends a little beyond these two points, your actual savings would
be a slightly greater than what we see here.

If your home's average heat loss is 0.170 kW per degree C and your
demand point is 13C, the numbers break down as follows:

Annual Heat Demand 12,738 kWh
Heat Pump Output 7,436 kWh
Heat Pump Input 2,481 kWh
Annual COP 3.00
Net Savings 4,955 kWh
Backup Requirement 5,303 kWh
Heat Pump Contribution 58.4%

If, in fact, your home's heat loss is a little higher (i.e., 0.20
kW/C) and your demand point is 15C (i.e., the other internal gains
previously mentioned are not quite as significant as first thought or
if you prefer to keep your home a little warmer), the numbers work out
as follows:

Annual Heat Demand 16,913 kWh
Heat Pump Output 9,118 kWh
Heat Pump Input 3,010 kWh
Annual COP 3.03
Net Savings 6,109 kWh
Backup Requirement 7,794 kWh
Heat Pump Contribution 53.9%

I believe you pay just over $0.101 per kWh, so your dollar savings
would be $502.00 and $618.00 respectively ($567.00 and $699.00
including federal and provincial taxes). By comparison, a
geo-exchange heat pump with an annual COP of 4 -- if that's a
reasonable number to use -- would reduce your annual heating costs by
$967.00 and $1,284.00, for an additional savings of $466.00 and
$666.00 respectively ($526.00 and $752.00 with PST & GST).

If the geo-exchange system you priced is $14,500.00 after rebate(s)
and the Fujitsu ductless unit is $3,500.00, say, after its $400.00
rebate, the $11,000.00 difference between these two options extends
your simple payback by an additional 15 to 20 years, or perhaps 10 to
15 years assuming a more rapid escalation in electricity costs. If
time permits and if it would be helpful to you, I can work out the NPV
numbers to more accurately gage the relative merits of both.

Cheers,
Paul