The ASHP installation process can be divided into the following five distinct steps. Generally, a homeowner will be interested in an ASHP retrofit when either an existing heating/cooling system fails or adding air conditioning system or when other upgrades are being completed on the home. The accompanying flowchart depicts the necessary steps that should be followed to ensure installation best practices for an ASHP installation.

Step 1: Job-Site Survey and Pre-Changeout

In existing buildings, an initial assessment of the existing heating and cooling system, ducting system (including duct disconnects /leaks), overall home condition (i.e. existing insulation, air leaks/bypass, etc.), and occupancy should be completed pre-quote. Identified issues should be addressed before installing any new equipment to ensure proper sizing and efficient operation of the ASHP system. This will improve occupants' comfort, reduce heating and cooling costs, reduce the size of equipment required and improves heat pump performance. If any ducting modifications are required in the case of centrally ducted ASHPs, they should also be made prior to installing any new equipment.

Step 2: Design (Sizing and Selection)

Correct sizing is important for the proper operation and economic viability of ASHP system. Oversizing equipment can lead to excessive cycling, reduced equipment life, lower efficiency, and ineffective summer dehumidification. CSA standard CAN/CSA- F280 combined with HRAI's "Residential Heat Loss and Heat Gain Manual" or TECA's Quality First® Heat Loss & Heat Gain software or equivalent are recommended for calculating heating and cooling loads for ASHP systems. For sizing of equipment, CSA standard CAN/CSA-C273.5-11 should be followed.

Step 3: Installation

ASHP installations should be completed by properly trained and qualified contractors. For instance, contractors should be properly training in heat pump systems, including knowledge of refrigeration, sizing, and air distribution.

Manufacturer training on specific system is recommended. Installations should also meet CSA standard CAN/CSA-C273.5-11 and all other required codes and standards and should be installed in a manner that optimizes the systems' performance and durability and occupant comfort. Ideally, the installation contractor should be a member of TECA and/or HRAI as well. Among other benefits, this will help reinforce continuing education requirements.

Step 4: Commissioning/Start-Up

Commissioning and start-up of the system must also be performed by appropriately trained and qualified contractors. At ASHP start-up, the necessary commissioning tests should be completed and logged to ensure the heat pump is operating according to the manufacturer's specifications.

Step 5: Education and Maintenance

Contractors should provide the commissioning checklist and manufacturer's information to the homeowner. Contractors should also review warranty information and operation and maintenance procedures for the new ASHP with the homeowner before leaving the site.