[Greenbuilding] Ductless Heat Pump Performance - November 2011

Paul Eldridge paul.eldridge at ns.sympatico.ca
Mon Dec 5 20:45:54 PST 2011

Hi Richard,

When I lived in Toronto, my first home was an old Victorian that was 
heated by a 30.0 kW electric furnace, and when the thermostat called for 
heat all 30.0 kW kicked on, the blower ran for however long then shut 
off, with this being repeated perhaps a hundred times a day during the 
coldest days of the year.  Compare this to our two ductless units that 
draw a few hundred watts each more or less continuously in mild weather 
and maybe a 1,000 or so watts when temperatures turn sharply colder.  
 From a utility's perspective, one is a sleeping collie curled up in 
front of the fire and the other the proverbial bull in a china shop (my 
gift to Nova Scotia Power: 

I just received our most recent power bill and as at November 24th our 
twelve month rolling average now stands at 10,998 kWh (space heating and 
cooling, domestic hot water, major appliances and all plug loads).  Over 
the next twelve months I hope to shave that by another 1,000 kWh.  The 
previous owners of this home in the year prior to our purchase consumed 
some 5,700 litres of fuel oil and if memory serves 14,600 kWh of 
electricity, so we've made good progress to date, but there's still more 
work to be done.

Our consumption data for the first five days of December: 


>Thanks for the details. So, when the temperature drops a  degree or two you
>only have an incremental (tiny) increase in power consumption. The
>implications are huge. If more homes installed these ductless units* with
>inverter technology* ( Nova Scotia is ideal with average winter
>temperatures of -3 degrees) the utility wouldn't have to do massive
>ramp-ups trying to cope with thousands of baseboards simultaneously
>demanding 1,500 kw - 4,500kw or oil furnace burners demanding 1.5 - 5 amps
>when the temperature drops. Also, many don't factor the electrical input of
>burner motors and distribution fans ( many running 24/7 through
>non-insulated leaky ducts in crawl spaces, garages and attics) when costing
>out their gas and oil central heating systems. The fact that one appliance
>is providing heating and air conditioning is very appealing.
>Very impressive.

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