Chat with us, powered by LiveChat

Not all cold climate heat pumps are equal

Many Canadians are taking advantage of the Canada Greener Homes Grant program and upgrading their home heating systems to a centrally ducted heat pump.  In order for a heat pump system to qualify for a grant the unit must be COLD CLIMATE CERTIFIED.  Even though a heat pump system is COLD CLIMATE CERTIFIED that does not mean that it will be the most efficient at heating your home.  One of the most recognized efficiency ratings for heat pump systems is known as the Heating Seasonal Performance Factor or HSPF.  The HSPF is a rating given to heat pump systems that represents the electrical consumption of a heat pump system, while operating in the heating mode.  Many homeowners are led to believe that the higher the HSPF rating of a heat pump the lower their heating costs are going to be.  This statement couldn’t be anymore false.  

As an example:

The Carrier 38MURAQ36 has an HSPF of 10.5 (Region IV) and can provide 35,200BTU/HR at -15C.  

The Lennox SL25XPV36 has an HSPF of 11 (Region IV) and can provide 26,640BTU/HR at -15C.

The heating performance between these two models is almost 30% in the difference and what this means is that although the Lennox system has a higher HSPF, the Carrier system will rely on the back up electric heater a lot less which equals a more efficient system overall.

All centrally ducted systems installed in Nova Scotia are required to have some form of auxiliary/back up heating system to augment the heat pump when the home is losing more heat than the heat pump can make up for.  In most cases the back up system is an electric heat element that is installed inside the heat pumps air handler.  When a heat pump can no longer provide 100% of the homes heating needs the electric heater comes on to augment the heat pump.  Both systems work together to maintain the temperature in the home.  The less a heat pump has to rely on the electric back up system the lower your power consumption is going to be; which means, more savings and money in your pocket.

Probably the most important efficiency rating that a homeowner should consider when purchasing a new centrally ducted heat pump system is the amount of heating output (BTU/HR) the system can provide at lower temperatures.  The Canada Greener Homes website uses a term called CAPACITY MAINTENANCE.  Capacity Maintenance is a calculation of how much heating a heat pump provides at -15C compared to the systems rated heating capacity.  For instance the Carrier 38MURAQ36 is rated at 40,000BTU/HR and has a capacity maintenance of 88% at -15C.  This means that the system will provide 88% of the rated heating value at -15C.

Another thing that needs to be considered is the heat pump sizing.  

Heat pumps and air conditioning systems are rated in what is called “TONS”.  A ton, as used in the HVAC field, is a term that describes how much heat and AC unit can remove from a home in one hour. The measurement for heat is the British thermal unit (BTU). One ton of air conditioning (or heat pump) can remove or provide 12,000 BTUs per hour.

Even though you may receive an estimate for the same tonnage of heat pump the total heating output value can range significantly from brand to brand.  This is why it is so important to understand the numbers and hire an experienced contractor that has the know how to properly size and provide a heat pump system for your homes specific needs.  In other words, your home may need a 3TON Carrier heat pump but if looking at a Daikin or Lennox brand you might need a larger system to offer the same heating output value or you’ll be relying heavily on the back up electric, gas or oil system to do bulk of the work.

We took some of the most common brands sold in Nova Scotia and did an analysis on the most efficient, COLD CLIMATE models in a 3TON capacity to show how wide of a variance there is between brands/models.

Here are our results:


Heating Capacity at +8C – 40,000BTU/HR

Heating Capacity at -15C – 35,200BTU/HR

AHRI REFERENCE # 208447883


Heating Capacity at +8C – 40,000BTU/HR

Heating Capacity at 15C – 33,600BTU/HR

AHRI REFERENCE # 203162003


Heating Capacity at +8C – 36,000BTU/HR

Heating Capacity at -15C – 29,880BTU/HR

AHRI REFERENCE # 205756419


Heating Capacity at +8C – 35,000BTU/HR

Heating Capacity at -15C – 28,000BTU/HR

AHRI REFERENCE # 206249117


LENNOX (SL25XPV-036-230A) 

Heating Capacity at +8C – 36,000BTU/HR

Heating Capacity at -15C – 26,640BTU/HR

AHRI REFERENCE # 207436328


Heating Capacity at +8C – 28,600BTU/HR

Heating Capacity at -15C – 20,020BTU/HR

AHRI REFERENCE # 207526332  


Heating Capacity at +8C – 27,400BTU/HR

Heating Capacity at -15C – 19,180BTU/HR

AHRI REFERENCE # 210791259



These are all INVERTER systems and all deemed a 3TON model; however you can see the wide variance in actual heating capability quite clearly.

Do your research and look into the actual performance and capability of the heat pump system you are considering.

SEER and HSPF ratings are important but as the example above shows the actual heating capacity of that system may not be what is needed for your home and the sizing of your system may be drastically off if your HVAC contractor isn’t aware of the heating output capability of the systems they sell.

The Carrier Performance 38MURA, 3TON model would have an output of 35,200BTU/HR at -15C 

The Daikin DZ17, 3TON model would have an output of 19,180BTU/HR at -15C 

The Carrier system has 50% more heating output value versus the Daikin which means that you will rely SIGNIFICANTLY more on your back up heating source to heat your home with the Daikin model than you would the Carrier.

If we look at a larger size Daikin DZ17 5TON model the total heating output at -15C is 32,400BTU/HR which still doesn’t meet the capability of Carrier’s 3TON Performance 38MURA

As you can see, one Cold Climate INVERTER heat pump system is NOT comparable to the other. In our example it takes a 5TON Daikin DZ17 INVERTER system to match the heating output of the Carrier Infinity 24 3TON model at -8.3C

When you’re considering the purchase of a new centrally ducted heat pump system for your home you should ask each one of the contractors to provide you with some heating information about the system(s) they are offering so that you can do a direct comparison of the brands you are considering. DO NOT just rely on the system TONNAGE, SEER or HSPF numbers.

error: Content is protected !!