Heat Pump Installation Checklist: What Should Be Included?

A heat pump installation is much more than replacing one outdoor unit with another. The final system includes the outdoor heat pump, indoor equipment, controls, electrical connections, refrigerant circuit, airflow system, condensate drainage, and—where applicable—ductwork and auxiliary heat.

A properly completed installation should also include system startup and commissioning. The equipment should not simply be switched on and left running without verifying airflow, controls, electrical operation, refrigerant-related conditions, drainage, heating and cooling operation, and other manufacturer requirements.

This heat pump installation checklist is designed to help homeowners understand what should be discussed before work begins, what should happen during installation, what should be checked at startup, and what documentation should be provided when the project is finished.

Quick Answer: What Should A Heat Pump Installation Include?

Installation Stage	What Should Be Included
Pre-Installation Assessment	Building load, existing equipment, electrical system, ducts and installation location
Equipment Selection	Correctly sized and compatible indoor/outdoor equipment
Permits	Required mechanical, electrical and other applicable permits
Outdoor Unit	Proper support, clearances, drainage and service access
Indoor Unit	Correct installation, airflow path, drainage and service access
Refrigerant Circuit	Correct piping, connections, evacuation, leak checking and charging
Ductwork	Appropriate supply/return airflow, sealing, insulation and static pressure where applicable
Electrical	Correct circuit, disconnect, wiring, grounding and controls
Thermostat	Compatible control and correctly configured heating/cooling stages
Auxiliary Heat	Correctly installed and configured backup heat where applicable
Condensate	Proper drainage and overflow protection where required
Commissioning	Operational measurements and functional testing
Handover	Documentation, warranty information, manuals and homeowner instructions

1. Confirm The Installation Scope Before Work Begins

Before the contractor arrives, the written proposal should clearly identify what is being installed.

At minimum, verify:

• Outdoor heat pump model
• Indoor air handler or coil model
• Thermostat or control model
• Auxiliary heat kit, if applicable
• Refrigerant type
• Electrical work
• Refrigerant-line work
• Duct modifications
• Condensate work
• Permits
• Equipment removal
• Startup and commissioning
• Warranty
• Total installed price

This prevents an important problem: discovering during installation that a component you assumed was included was actually excluded from the contract.

2. Verify The Heat Pump Size

The contractor should have a technical basis for the selected capacity.

Ideally, the equipment should be selected using a building load calculation rather than a simple square-footage rule.

The calculation considers factors such as:

• Building size
• Insulation
• Windows
• Doors
• Wall construction
• Roof construction
• Air leakage
• Indoor design temperature
• Outdoor design temperature
• Solar exposure
• Internal heat gains

The goal is to determine the heating and cooling requirements of the building and then select equipment that can operate appropriately across those conditions.

For more information, see How To Size A Heat Pump For Your Home.

3. Check Heating Capacity, Not Just Nominal Tonnage

A heat pump’s nominal tonnage does not tell you everything about its heating performance.

Before installation, check the manufacturer’s published performance data for temperatures relevant to your location.

Useful information can include:

• Heating capacity at 47°F
• Heating capacity at 17°F
• Heating capacity at 5°F where relevant
• Minimum operating temperature
• Maximum operating temperature
• Auxiliary heat capacity

The exact values vary substantially between models.

In colder climates, this information can be especially important because the system’s heating capacity and efficiency can change as outdoor temperature falls.

4. Verify The Indoor And Outdoor Equipment Match

The indoor and outdoor components should be compatible with each other.

For systems where certified matched combinations are available, ask for the applicable matched-system information.

Do not assume that every indoor coil or air handler can be paired with every outdoor heat pump.

The combination can affect:

• SEER2
• EER2
• HSPF2
• Heating capacity
• Cooling capacity
• Airflow requirements
• Control compatibility

The exact model numbers should therefore be recorded before installation.

5. Confirm The Refrigerant

Modern heat pumps can use different refrigerants depending on the equipment.

Common refrigerants encountered in residential equipment include R-410A, R-32 and R-454B.

The refrigerant must match the equipment design.

Do not allow a contractor to treat refrigerants as interchangeable simply because they are used in similar applications.

Before installation, verify:

• Refrigerant type
• Equipment compatibility
• Line-set requirements
• Manufacturer charging procedure
• Refrigerant safety requirements

See Heat Pump Refrigerants Explained: R 410A, R 32 And R 454B for a detailed explanation.

6. Confirm Required Permits

Permit requirements vary by jurisdiction and by the work being performed.

A heat pump project may involve mechanical, electrical, building or other local requirements.

Before installation, establish:

• Which permits are required
• Who obtains them
• Who pays the fees
• Who schedules inspections
• Who corrects inspection deficiencies

Put this responsibility in writing.

7. Inspect The Existing System Before Removal

If the installation is replacing an existing HVAC system, the contractor should understand the existing installation before removing it.

The inspection should consider:

• Existing equipment capacity
• Electrical circuit
• Electrical panel
• Refrigerant line set
• Ductwork
• Return-air system
• Supply-air system
• Thermostat wiring
• Condensate drainage
• Equipment location

Existing problems should be identified before the new system is installed rather than discovered after startup.

8. Remove The Old Equipment Properly

The removal process may involve refrigerant recovery, electrical disconnection, mechanical disassembly and equipment disposal.

Ask the contractor:

• Is old equipment removal included?
• Is refrigerant recovered properly?
• Is disposal included?
• Will the work area be protected?
• Will debris be removed?

The exact procedures depend on the equipment and local requirements.

9. Install The Outdoor Unit On A Suitable Base

The outdoor unit needs a stable installation surface that supports its weight and allows appropriate airflow and drainage.

Consider:

• Level support
• Equipment clearances
• Airflow
• Service access
• Drainage
• Snow accumulation where applicable
• Flooding risk where applicable
• Vibration
• Noise

The contractor should follow the manufacturer’s required clearances rather than using an arbitrary distance.

10. Consider Outdoor Unit Drainage

During heating operation, moisture can condense and freeze on the outdoor coil. During defrost, accumulated frost is removed and water can drain from the outdoor unit.

The installation should therefore provide appropriate drainage.

In freezing climates, the contractor should consider whether the drainage arrangement could allow water to refreeze beneath or around the equipment.

11. Provide Appropriate Service Clearance

The outdoor unit should remain accessible for maintenance and repair.

A unit squeezed into a narrow space may technically operate while making future service unnecessarily difficult.

Ask the contractor whether the final location satisfies the manufacturer’s clearance and service requirements.

12. Install The Indoor Equipment Correctly

The indoor air handler, coil or other indoor equipment must be installed in a way that supports proper airflow, drainage and maintenance.

Check:

• Equipment support
• Leveling where required
• Supply-air connection
• Return-air connection
• Filter access
• Condensate drainage
• Service access
• Electrical connections

13. Check Return-Air Design

Return air is just as important as supply air.

An undersized or restrictive return system can increase static pressure and reduce airflow.

During installation, the contractor should consider:

• Return duct size
• Return grille size
• Filter pressure drop
• Air-handler requirements
• Static pressure

For ducted systems, return-air limitations should not be ignored simply because the outdoor unit is new.

14. Check Supply-Air Ductwork

The supply side should also be compatible with the equipment’s airflow requirements.

Potential problems include:

• Undersized ducts
• Excessive bends
• Crushed flexible duct
• Leaking connections
• Insufficient insulation
• Restricted registers

Where modifications are required, they should be completed before final commissioning.

15. Install And Seal Duct Connections

Connections between the air handler and duct system should be properly sealed.

Unsealed joints can allow conditioned air to escape into unconditioned spaces.

Pay particular attention to:

• Supply plenum
• Return plenum
• Air-handler connections
• Branch connections
• Access panels
• Filter cabinet

16. Verify Duct Insulation

Duct insulation matters when ducts pass through unconditioned areas such as attics, crawl spaces and garages.

Insulation requirements depend on location, construction and local codes.

The contractor should repair damaged insulation and address exposed sections where appropriate.

17. Install The Refrigerant Line Set

The refrigerant lines connect the outdoor and indoor portions of the heat pump.

The installation should follow the equipment manufacturer’s requirements for:

• Line diameter
• Maximum length
• Vertical elevation
• Insulation
• Routing
• Support
• Connections

If an existing line set is being reused, the contractor should verify that it is suitable for the new equipment.

18. Protect The Refrigerant Tubing

Refrigerant tubing should be routed and supported so that it is protected from physical damage.

Insulation on the appropriate line should also be properly installed and protected from environmental damage.

Improperly supported or damaged tubing can create problems long after installation.

19. Leak-Test The Refrigeration System

Before final operation, the refrigeration circuit should be checked for leaks using procedures appropriate for the equipment and refrigerant.

Ask the contractor:

“How will you verify that the refrigeration circuit is leak-free before charging and startup?”

The answer should involve a defined installation procedure rather than simply observing whether the system appears to run.

20. Evacuate The Refrigeration Circuit

Proper evacuation removes unwanted air and moisture from the refrigeration circuit before charging and operation.

The contractor should follow the equipment manufacturer’s installation procedure.

The evacuation process is especially important because non-condensable gases and moisture can interfere with refrigeration-system operation.

21. Verify Refrigerant Charge

The final refrigerant charge should be established according to the equipment manufacturer’s requirements.

The correct procedure depends on the system design and operating conditions.

Do not assume that a fixed amount of refrigerant can be used for every installation.

Line length, equipment configuration and manufacturer instructions can affect charging requirements.

22. Install The Electrical Supply

The electrical installation should be sized and installed according to the equipment requirements and applicable codes.

Check:

• Voltage
• Breaker
• Wire size
• Disconnect
• Grounding
• Conduit
• Equipment connections

The exact electrical requirements depend on the equipment model.

23. Check Auxiliary Heat Electrical Requirements

Electric auxiliary heat can substantially increase electrical demand.

If the system includes resistance heat, verify:

• Heat-kit capacity
• Breaker requirements
• Wire requirements
• Electrical panel capacity
• Control wiring
• Staging

A system should not be installed with an auxiliary heat kit that exceeds the home’s available electrical capacity.

24. Install The Thermostat Or Control

The thermostat should be compatible with the exact heat pump system.

Depending on the equipment, the control may need to manage:

• Heating
• Cooling
• Multiple compressor stages
• Variable-capacity operation
• Auxiliary heat
• Emergency heat
• Defrost-related operation
• Outdoor temperature information

After installation, the contractor should verify each applicable operating mode.

25. Configure Auxiliary And Emergency Heat Correctly

Auxiliary heat and emergency heat are not necessarily the same thing.

Auxiliary heat can operate automatically when the heat pump needs supplemental capacity.

Emergency heat is generally a user-selected operating mode in which the backup heating source is used instead of normal heat-pump operation.

The contractor should demonstrate both functions where applicable.

26. Install Condensate Drainage

Cooling operation produces condensate that needs to be safely removed.

The installation may require:

• Primary drain
• Secondary drain
• Condensate pump
• Drain pan
• Overflow protection
• Proper drain termination

Local codes and equipment configuration determine the exact requirements.

27. Verify Condensate Flow

Simply connecting the drain pipe is not enough.

The contractor should verify that water can flow through the drainage system without backing up.

Check that the drain does not create a risk of water damage to ceilings, walls or equipment.

28. Check Airflow

Airflow is one of the most important commissioning measurements for a ducted heat pump.

The correct airflow depends on the equipment and operating mode.

The contractor should verify that the system is operating within the manufacturer’s specified airflow range.

Possible measurement methods vary by equipment and installation.

29. Measure Static Pressure Where Applicable

Static pressure provides information about airflow resistance in the duct system.

Excessive static pressure can result from:

• Undersized ducts
• Restrictive filters
• Dirty coils
• Blocked returns
• Improper dampers
• Poorly designed duct transitions

For ducted systems, ask whether total external static pressure will be measured during commissioning.

30. Check Filter Pressure Drop

The filter should not create excessive resistance for the system.

Filter pressure drop depends on:

• Filter size
• Filter type
• Filter loading
• Airflow
• Filter design

A larger filter surface area can sometimes reduce pressure drop, but the final arrangement should be compatible with the equipment and duct system.

31. Test Cooling Operation

Even if the heat pump is being installed primarily for winter heating, cooling operation should be verified where the system provides cooling.

The contractor should confirm:

• Compressor operation
• Indoor blower operation
• Thermostat response
• Condensate drainage
• Appropriate operating temperatures
• Control staging

32. Test Heating Operation

Heating operation should also be verified.

Check:

• Heat-pump heating mode
• Indoor airflow
• Thermostat response
• Outdoor unit operation
• Backup heat staging
• Control sequence

33. Verify Defrost Operation

Air-source heat pumps can develop frost on the outdoor coil under appropriate weather conditions.

The system uses a defrost cycle to remove accumulated frost.

The contractor should verify that the defrost controls are connected and configured according to the manufacturer’s requirements.

During defrost, homeowners may notice steam, water or a change in sound. These can be normal characteristics of the process.

34. Check Outdoor Fan Operation

The outdoor fan plays an important role in moving air across the outdoor coil.

The contractor should verify that it operates correctly in the applicable heating and cooling modes.

Unusual vibration, scraping, intermittent operation or abnormal noise should be investigated before the installation is considered complete.

35. Verify Reversing Valve Operation

The reversing valve changes the direction of refrigerant flow so that the system can switch between heating and cooling.

The contractor should verify that the system changes modes correctly.

A wiring or control problem can cause the heat pump to operate in the wrong mode.

36. Check Thermostat Staging

Advanced heat pumps may have multiple operating stages or variable-capacity control.

The installer should verify that the thermostat or communicating control properly commands the available operating modes.

Incorrect staging can affect comfort and energy consumption.

37. Check Auxiliary Heat Activation

If auxiliary heat is installed, the contractor should verify that it activates when commanded by the control system.

The test should also confirm that the correct heating element or backup source is operating and that the electrical system is functioning correctly.

38. Verify Emergency Heat

If the system provides an emergency-heat mode, the contractor should explain how to activate it and what happens when it is selected.

The homeowner should understand that emergency heat is not necessarily intended to be used as the normal heating mode.

39. Check Electrical Measurements

Commissioning should include appropriate electrical checks for the equipment.

Depending on the system, measurements can include:

• Supply voltage
• Operating current
• Electrical connections
• Control voltage
• Auxiliary heat operation

Measurements should be compared with manufacturer requirements and applicable installation procedures.

40. Check For Abnormal Noise And Vibration

Some heat-pump sounds are normal.

However, excessive vibration, rattling, scraping or unusual compressor noise should be investigated.

Possible causes can include:

• Loose panels
• Improper mounting
• Refrigerant piping vibration
• Fan imbalance
• Duct vibration
• Equipment resonance

41. Check Outdoor Clearances

Verify that vegetation, walls, fences or other objects do not obstruct the outdoor unit’s required airflow.

Do not assume that a unit installed close to a wall is automatically acceptable simply because it physically fits.

The manufacturer’s clearance requirements should govern the installation.

42. Check Indoor Access

Filters, electrical components, coils and other serviceable components should remain accessible.

An installation that makes routine maintenance unnecessarily difficult can create problems later.

43. Check The Finished Duct System

After the installation is complete, inspect visible duct connections.

Look for:

• Unsealed joints
• Damaged insulation
• Collapsed flexible duct
• Disconnected sections
• Improperly supported ductwork

44. Check The Work Area

The contractor should leave the installation area reasonably clean.

Confirm that:

• Packaging has been removed
• Old equipment has been removed if included
• Construction debris has been cleaned
• Access panels are installed
• Electrical covers are secured
• Equipment is protected and ready for operation

45. Record The Equipment Information

Before the contractor leaves, record:

• Outdoor model number
• Indoor model number
• Serial numbers
• Thermostat model
• Refrigerant type
• Auxiliary heat-kit model
• Installation date

Take photographs of the equipment nameplates if permitted.

46. Register The Equipment Warranty

Some manufacturer warranties require registration within a specified period.

Ask:

• Who registers the equipment?
• When must registration occur?
• Do you receive confirmation?
• What documentation should the homeowner retain?

Do not assume that warranty registration happens automatically.

47. Receive The Installation Documentation

A professional handover should provide useful documentation.

Ask for:

• Installation manual
• Owner’s manual
• Warranty information
• Equipment model numbers
• Serial numbers
• Commissioning information where provided
• Permit documentation where applicable
• Thermostat instructions

48. Learn How To Operate The System

The contractor should explain basic operation before leaving.

The homeowner should understand:

• How to select heating
• How to select cooling
• How to change the temperature
• How auxiliary heat operates
• How emergency heat operates
• How to replace the filter
• How to recognize a fault code
• When to call for service

49. Ask About Normal Heat Pump Sounds

Homeowners sometimes interpret normal heat-pump operation as a fault.

Depending on the equipment, normal sounds can include:

• Compressor operation
• Outdoor fan operation
• Reversing-valve changes
• Defrost operation
• Water dripping during defrost
• Temporary steam during defrost

The contractor should explain which sounds are expected and which require service.

50. Establish The Maintenance Schedule

Ask the installer what maintenance is recommended for the specific equipment.

Homeowner maintenance commonly includes appropriate filter replacement and keeping outdoor airflow clear.

Professional maintenance may involve deeper inspection and measurements.

See Heat Pump Maintenance Guide: What Homeowners Need To Know for a detailed maintenance checklist.

Heat Pump Installation Commissioning Checklist

Commissioning Item	Completed?
Heating operation tested	☐
Cooling operation tested	☐
Thermostat operation verified	☐
Auxiliary heat tested where applicable	☐
Emergency heat tested where applicable	☐
Defrost controls verified	☐
Airflow checked	☐
Static pressure checked where applicable	☐
Electrical operation checked	☐
Refrigerant-related installation checks completed	☐
Condensate drainage verified	☐
Outdoor clearances checked	☐
Unusual noise/vibration checked	☐
Installation documentation received	☐

Heat Pump Installation: What The Homeowner Should Check Visually

Homeowners should not attempt electrical or refrigerant work themselves. However, several aspects of the completed installation can be visually inspected.

• Outdoor unit is stable
• Outdoor unit has appropriate clearance
• Outdoor unit is not buried in vegetation
• Indoor equipment is accessible
• Filter is accessible
• Duct connections appear properly finished
• Insulation is intact
• Condensate drain is connected
• Thermostat operates normally
• No obvious water leakage is present
• No unusual vibration is present

What Homeowners Should Not Attempt

Heat pumps contain electrical equipment and pressurized refrigerant circuits.

Homeowners should not attempt to:

• Open the refrigeration circuit
• Add refrigerant
• Modify electrical wiring
• Change refrigerant piping
• Bypass safety controls
• Modify compressor controls
• Disable defrost protection

These tasks should be handled by appropriately qualified professionals.

Common Installation Problems

Problem	Potential Consequence
Incorrect sizing	Comfort, cycling or backup-heat issues
Restricted airflow	Reduced performance and possible equipment problems
Poor duct sealing	Conditioned-air loss
Incorrect refrigerant procedure	Reduced performance or reliability problems
Incorrect controls	Improper staging or auxiliary-heat operation
Poor drainage	Water leakage or freezing problems
Insufficient outdoor clearance	Restricted airflow and service difficulties
Improper commissioning	Installation problems may remain undetected

Frequently Asked Questions

1. What is the most important part of heat pump installation?

There is no single step. Proper equipment selection, installation, airflow, refrigerant work, electrical work, controls and commissioning all contribute to final system performance.

2. Should a heat pump installation include a load calculation?

A building load calculation is an important basis for selecting equipment capacity and is preferable to relying solely on square-footage rules.

3. Should I get the exact model numbers?

Yes. Record the outdoor, indoor and control model numbers before installation.

4. Does the indoor unit matter?

Yes. The indoor and outdoor components form a system, and their combination can affect rated capacity and efficiency.

5. Should the contractor inspect my existing ducts?

Yes, when installing a ducted heat pump. Duct size, leakage, insulation, airflow and static pressure can affect system performance.

6. Should airflow be measured?

For ducted systems, airflow verification is an important part of commissioning. The appropriate target depends on the equipment manufacturer’s requirements.

7. Should static pressure be measured?

For ducted systems, static-pressure measurement can help identify excessive resistance and airflow problems.

8. Should the refrigerant charge be checked?

Yes. The contractor should follow the manufacturer’s procedure for establishing and verifying the refrigerant charge.

9. Can the old refrigerant line set be reused?

Sometimes, but compatibility, size, condition, length and manufacturer requirements must be evaluated.

10. Does every heat pump need auxiliary heat?

Not necessarily. System design, climate and building requirements determine whether supplemental heat is appropriate.

11. Is auxiliary heat the same as emergency heat?

No. Auxiliary heat can operate automatically under certain conditions, while emergency heat is generally a manually selected backup operating mode.

12. Should the contractor test defrost?

The defrost system and associated controls should be verified according to the equipment manufacturer’s commissioning procedure.

13. Why does my outdoor heat pump produce steam?

During a defrost cycle, frost on the outdoor coil can melt and produce visible water vapor or steam. This can be normal.

14. Should the outdoor unit be perfectly level?

The installation should meet the manufacturer’s requirements for support and positioning. The exact requirement depends on the equipment.

15. How much clearance does a heat pump need?

There is no universal clearance distance. Follow the manufacturer’s installation requirements and applicable codes.

16. Should condensate drainage be tested?

Yes. The contractor should verify that condensate can drain properly and that required overflow protection is functioning.

17. Should the thermostat be replaced?

Not always. The existing thermostat can sometimes be reused, but compatibility with the new heat pump must be confirmed.

18. Should I receive the equipment manuals?

Yes. Keep the owner’s manual and installation/warranty documentation for future maintenance and service.

19. Should I photograph the model and serial numbers?

Yes. Keeping photographs of the equipment nameplates can make future warranty and service communication easier.

20. Should equipment warranty registration be completed?

If the manufacturer requires registration, complete it within the required period and retain proof of registration.

21. What should commissioning include?

Depending on the system, commissioning can include heating and cooling operation, airflow, static pressure, electrical measurements, controls, auxiliary heat, defrost, drainage and refrigeration-related checks.

22. Can I inspect the installation myself?

You can perform a visual inspection and verify documentation, but electrical and refrigerant work should be left to appropriately qualified professionals.

23. Should the contractor explain maintenance?

Yes. The homeowner should know how to maintain filters, keep outdoor airflow clear and recognize conditions that require professional service.

24. When is a heat pump installation considered complete?

It should be considered complete after the equipment is installed, required work is finished, applicable inspections are completed, the system is commissioned, documentation is provided and the homeowner understands basic operation.

25. What should I do if the system does not perform correctly immediately after installation?

Contact the installing contractor and describe the symptoms. Do not attempt to modify refrigerant, electrical connections or safety controls yourself.

Final Heat Pump Installation Checklist

Installation Item	Check
Load calculation reviewed	☐
Equipment model numbers verified	☐
Indoor/outdoor match verified	☐
Heating capacity reviewed	☐
Refrigerant identified	☐
Permits clarified	☐
Electrical requirements checked	☐
Outdoor unit properly supported	☐
Outdoor clearances verified	☐
Indoor unit properly installed	☐
Supply and return ducts checked	☐
Filter arrangement checked	☐
Refrigerant lines installed correctly	☐
Leak testing completed	☐
System evacuated according to procedure	☐
Refrigerant charge verified	☐
Condensate drainage tested	☐
Thermostat configured	☐
Auxiliary heat tested where applicable	☐
Heating tested	☐
Cooling tested	☐
Defrost operation verified	☐
Airflow verified	☐
Static pressure checked where applicable	☐
Electrical operation checked	☐
Warranty information received	☐
Manuals received	☐
Model and serial numbers recorded	☐
Homeowner operation explained	☐

Final Takeaway

A heat pump installation should be viewed as a complete system installation rather than an equipment replacement.

Before work begins, the contractor should establish the appropriate equipment size, confirm the indoor and outdoor equipment combination, inspect the existing electrical and airflow systems, and define the complete installation scope.

During installation, the refrigerant circuit, electrical system, ductwork, condensate drainage, controls and equipment mounting should be completed according to the equipment manufacturer’s requirements and applicable codes.

After installation, the most important step is commissioning. Heating, cooling, airflow, controls, auxiliary heat, defrost, drainage and other applicable operating conditions should be verified before the project is considered finished.

Finally, the homeowner should receive the equipment documentation, warranty information, model and serial numbers, operating instructions and maintenance guidance.

A detailed installation checklist does not guarantee perfect performance, but it gives the homeowner a much better way to verify that the major parts of the project have actually been addressed.

For the contractor-selection process, see How To Choose A Heat Pump Contractor.

For comparing proposals before installation, see How To Compare Heat Pump Installation Quotes.

For ongoing care after installation, see Heat Pump Maintenance Guide: What Homeowners Need To Know.

For the broader equipment-selection guide, see Best Heat Pumps In The USA.