A rated 2 ton air conditioner (built in) is standard for houses up to 1200 or 1300 square feet.
Rule of thumb which works is 1 ton for every 600 sq foot of building.
1 ton = 12,000 BTU.
An efficient 2 ton built in unit cost of operation:
Power: 208 Volts at 13.5 amp = 2808 watts/hour of use.
Power Line charge .02 kwh
Power Contract .09 kwh
Power charge delivered 11 cents per kwh
Furnace motor efficient or semi efficient 7 amps @ 110 volt = 770 watts/hour
Total operational power 3578 watt/hour
Total operational cost 3.578 kwh X .11 per kwh = 39.3 cents per hour
This works out to $3.93 for 10 hours of continuous operation.
With reasonable insulation and decent windows one can reasonably expect a 60% duty cycle.
Providing your furnace fan shuts down with the air conditioning, this would leave you a bottom line of $2.36 per day for air conditioning.
Having said this, I see where ENMAX has again increased their contract rate and incorporated a per month charge on the same path the EPCOR has found a success.
Between their monthly increase and their add on charges they have again increased their rates by 1 cent kwh or profits by 25%. EPCOR on the other hand has dropped almost 1 cent.
John Clark