I found the answer myself - it would seem they are exempt! And not just the Heat Pumps, but Air Conditioners in the EV too!
From the Canadian Government website publication with the law description: http://www.cra-arc.gc.ca/E/pub/et/x3-1/x3-1-e.html
Goods taxable
5. The following goods are subject to an excise tax:
fuel-inefficient automobiles (green levy);
air conditioners designed for use in automobiles, station wagons, vans and trucks; and
gasoline, diesel fuel, aviation gasoline, and aviation fuel.
...
Automotive air conditioners
13. Section 7 of Schedule I states that air conditioners designed for use in automobiles, station wagons, vans or trucks are subject to an excise tax of $100, whether:
separate, or
included as permanently installed equipment in an automobile, station wagon, van or truck, at the time of sale or importation of the vehicle by the manufacturer or importer thereof.
...
Exceptions
17. The excise tax on air conditioners designed for automobiles, station wagons, vans or trucks applies only to those that are powered by the engines or power trains of the vehicles mentioned. Air conditioners that are powered by separate motors, propane or electricity are not subject to this tax.
...
So it would seem, if you have purchased a Soul EV Luxury (as it is now called in Canada), you should not be paying the $100 AC tax!
