Photograph of building damage near Los Angeles 2000 © Daniel Friedman Heat Pump Defects List & Home Inspection Education

  • DEFECTS LIST - HEAT PUMP - CONTENTS: Heat pump inspection points and defects list. Lists of important heat pump system defects for residential buildings. What does a home inspector need to know about heat pumps? Home inspection training and education curriculum recommendations for heat pump systems
  • POST a QUESTION or READ FAQs about home & building inspection courses, standards, & defect checklists for heat pump systems

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This article lists significant heat pump system defects, definitions, and home inspection education topics.

This article series, beginning at BUILDING DEFECTS LISTS, provides lists of common building defects and basic defect knowledge that also outline recommended curriculum content for home inspector education.

The building defects and inspection points listed in these articles also guide homeowners and home buyers to building areas that merit careful attention and often point areas of safety concern or important maintenance and repair tasks. Page top heat pump sketch courtesy of Carson Dunlop Associates.

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Home Inspection Education Curriculum - Heat Pumps

5.2   Heat Pump Inspection Points, Defects, Knowledge Base Requirements

5.2.1 Knowledge Base Recommended for Heat Pump Inspections

1.    Describe the function of a residential heat pump system.

2.    Describe these types of heat pumps: air-to-air, air-to-water, air-to-ground. Include an operating cycle description.

3.    Describe the principles of operation of heat pumps including terms such as Co-efficient of Performance (COP), balance point and auxiliary heat.

4.    List the materials and components of a typical air-to-air heat pump including compressor, the outdoor coil, the indoor coil, the outdoor fan, the indoor fan, refrigerant lines, reversing valve, expansion devices, thermostat, auxiliary heat, indoor fan, outdoor fan, condensate tray and condensate lines, duct  system, duct insulation, air filter.

5.    Describe the features of  adequate installation and repair technique for heat pumps.

6.    Define the following terms as they relate to residential heat pumps:

  • latent heat vaporization,
  • back-up heat,
  • defrost cycle,
  • timed defrost,
  • demand defrost,
  • water source heat pumps,
  • ground source heat pumps,
  • heating load,
  • cooling load,
  • two stage compressors,
  • heat sink,
  • heat source,
  • outdoor temperature sensor,
  • two stage thermostats,
  • triple split systems,
  • accumulator,
  • compression ratio,
  • time and temperature defrost,
  • seasonal energy efficiency ratio (SEER),
  • heating seasonal performance factor (HSPF).

7.    Outline the typical life expectancy of residential heat pumps.

8.    Identify the codes or standards which apply to residential heat pumps in your area.

5.2.2 Inspection skills for heat pump inspections

1.    Describe the inspection procedure for heat pumps, including how to differentiate between heat pumps and air conditioning systems.

2.    Identify the common defects listed on the next page.

3.    Describe the implications of each defect.

4.    Identify safety issues for the inspector and occupant of the home (same as air conditioning).

2. Communicate findings to client verbally and in writing, recommending corrective actions where needed.

List of Typical Heat Pump System Defects that can be Observed by Visual Inspection

Heat Pump Capacity      

• Oversized for cooling

• Undersized for heating - review backup heat

Outdoor Condensing Coils

• Clothes dryer or water heater exhaust too close

• Corrosion

• Damaged

• Dirty

• Iced up

• Poor location

Heat Pump Compressor / Condenser Unit Defects                                   

• Electric wires too small        

• Excess electric current draw

• Excess noise or vibration   

• Inadequate cooling

• Inoperative in heating or cooling mode

• Missing electrical shutoff 

• Out of level  

• Running continuously 

• Short cycling 

• Wrong fuse or breaker size 

Indoor Evaporator Coil Defects

• Corrosion

• Damage

• Dirty

• Frost

• No access to coil

• Temperature split too low

• Temperature split too high

• Top of coil dry in cooling mode

. Watch out: these inspection lists do not list all possible defects for the systems discussed, and not all home or building inspectors will examine all of the items listed here. CONTACT us to suggest corrections or additions to articles at this website.

Also see HEAT PUMP SUBSYS DEFECTS LIST and see CONDENSATE HANDLING, A/C and DUCT SYSTEM & DUCT DEFECTS and see these heat pump article groups:

These curriculae and building defect lists are based on smilar curriculum documents first prepared by Joe Scaduto, an ASHI member who prepared course material for Northeastern University's Building Inspection Certificate program in 1988, subsequently by DF, InspectApedia's editor, for New York University ca 1988 and later, with others, recommended to ASHI, the American Society of Home Inspectors.

The curriculum and lists of defects are informed by additional analysis of the process of home inspection that was developed beginning Calgary, AB for Canadian and U.S. home inspector education and certification examinations in 1997. Other early contributors to home inspection education in the U.S. and Canada include Dr. Jess Aronstein, Alan Carson, Mike Casey, Mark Cramer, John Cox, Dwight Barnett, Douglas Hansen, Rick Heyl, Larry Hoytt, Bill Merrill, Kevin O'Malley, Dennis Robitalille, Keith Peddie, Pat Porzio, Roger Robinson. ASHI did not adopt this material though currently that association as well as others offer extensive HOME INSPECTOR EDUCATION material.


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