Additional Considerations When Choosing a Heat Pump For Space Heating
Air Flow
Heat pump systems require 20-30% higher air flow rates than conventional forced air furnaces.(1) This is to compensate for lower temperatures of the heated air. In many cases, existing ductwork can handle the increased flow rates but it is something to check. NRCan has a guide that provides instructions on how to calculate your duct capacity (see p 16 of the guide).
Electrical Needs
Heat pumps that supply all of a home’s heating requirements will add circuits to the electrical panel that may trigger the need for an electrical panel or electrical service upgrade. Sometimes these upgrades can be avoided: by using a smaller backup resistance heater, by having an electrician perform a historical load calculation to demonstrate extra capacity on the panel, by using load share devices or smart panels. Be sure to ask your installer if an upgrade may be required and always ask about ways to avoid such upgrades. You can check the size of the electrical panel (aka fuse box or circuit breaker panel) using the instructions found here. The best way to determine the cable connection to your home is to call your electrical utility.
Sizing
A heat pump system is sized based on the actual heating needs of the house. A home energy audit is a good way to get an estimate of the home’s actual heating needs or an installer can do a heating load calculation. A larger system can move more heat, meeting a home’s needs at lower outdoor temperatures, but if oversized, systems will be less efficient and will have shorter lifespans.
Locating Equipment
ASHPs and DFHPs have both an inside component that is installed in the air ducts or a unit that mounts on the wall/ceiling, and an outside unit that absorbs or releases heat. These units come in different shapes and sizes. Outside units should be located in a place with good airflow, drainage, accessibility, and free from possible obstructions such as snow drifts or plants.
Noise
Modern heat pumps are quieter than older models but they do make noises similar to that of air conditioners: condenser fans whir and compressors make a droning sound. Ultra quiet models are available. ... Noise can also be reduced through careful siting of the unit and strategic use of plants, for more information, look to Vancouver’s heat pump noise guide.
Choosing a Contractor
It is important to seek out installers that are well informed about heat pumps and have experience installing the type of system you are interested in. The HRAI (Heating, Refrigeration and Air Conditioning Institute of Canada) has a qualified contractor locator and all manufacturers have lists of qualified contractors on their websites. ... The HVAC (Heating Ventilation and Air Conditioning) industry has been slow to adopt and promote ASHPs and HPWHs. Some heating system professionals may be misinformed about the performance of heat pumps, unaware of the existence of HPWHs, or just wary of trying something different. The industry is accustomed to replacing like with like and representatives may be hesitant to risk their reputation by recommending systems that they are less familiar with. Ask around to find reputable installers that are knowledgeable, and it is always advisable to seek several quotes.
Availability and Installation Time
Heat pump systems take longer to install than gas furnaces and other conventional equipment. It is therefore recommended to do your research in advance and talk to an installer about how much life your current system has left and what work can be done in advance.
Environmental Impacts of Refrigerants
... Most current ASHPs use R-410a, a refrigerant with a low ozone depleting potential but high global warming potential (global warming potential of 2088(2)). This refrigerant is gradually being phased out in accordance with the Kigali Agreement(3). Although relatively small volumes of refrigerant are used in heat pump systems and they are well sealed in, a loss of performance or a system lockout could indicate a refrigerant leak and should be investigated promptly. Refrigerants with low ozone depleting potential and low global warming potential are coming on the market soon.
Radiator and In-Floor Systems
Homes that use radiators or in-floor systems with pumped water can also make the switch to heat pumps. Air to water heat pumps are designed to heat or cool the water used in these hydronic systems.
(2) Rajendran, R. (2011). Refrigerants update. [webinar]. Emerson Climate Technologies Inc. Retrieved from https://www.epa.gov/sites/production/files/documents/RefrigerantUpdates.pdf
(3) Polonara, Fabio & Kuijpers, Lambert & Peixoto, Roberto. (2017). Potential impacts of the Montreal Protocol Kigali Amendment to the choice of refrigerant alternatives. International Journal of Heat and Technology. 35. S1-S8. https://www.researchgate.net/publication/320038190_Potential_impacts_of_the_Montreal_Protocol_Kigali_Amendment_to_the_choice_of_refrigerant_alternatives
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