Heat pump systems require 20-30% higher air flow rates than conventional forced air furnaces. 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 get your installer to check when preparing a quote. NRCan has a guide that provides instructions on how to calculate your duct capacity (see p 16 of the guide).
Heat pumps that supply all of a home’s heating requirements may require a 200 amp electrical panel. When getting a quote, be sure to ask if an upgrade is required. Some homes already have a 200 amp panel, some will require an upgrade of the panel, and some will also require an upgrade of the cable connection to the home. 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.
A heat pump system is sized based on the actual heating needs of the house. A home energy audit is an ideal way to estimate the actual heating needs. A larger system can move more heat, meeting a home’s needs at lower outdoor temperatures, but if oversized, some systems will be less efficient at more moderate temperatures causing it to turn on and off more frequently which shortens its lifespan.
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.
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 or even considering alternatives such as HPWHs. 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 are less common than conventional heating systems and there may be delays in receiving and installing the equipment. Installation can also take several days. This is not good news if your furnace breaks down in the middle of a cold snap. 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 appear to use R-410a, a refrigerant with a low ozone depleting potential but high global warming potential (global warming potential of 2088). This refrigerant is gradually being phased out in accordance with the Kigali Agreement. 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.