This article is derived from my personal experience as a Real Estate Agent, HVAC contractor, and presently a Home Inspector based in Clarksville, TN. and it is my opinion, formulated solely through my personal experiences in these fields.

 This particular subject costs Home-buyers, Real Estate Agents and Home Inspectors, a substantial amount of money annually when the buyer's expectations are not met after their HVAC system, which is a mechanical device that can fail at any moment, does in fact fail.

 Who is to blame?

 When and how are HVAC units inspected is covered under several “Standards”, beginning with the State of Tennessee home inspection law, Home Inspector Associations and often improperly taught by Home Inspection Schools.

 The state of Tennessee requires that the inspector shall:

 A. Describe: the energy sources and cooling equipment type

B. Operate the systems using normal operating controls (thermostat).

C. Open readily openable access panels provided by the manufacturer or installer for routine homeowner maintenance.

 The inspector is not required to:

 A. Operate cooling systems when weather conditions or other circumstances may cause equipment damage.

B. Observe Non-Central air conditioner's (window units).

C. Observe the uniformity or adequacy of cool air supply to various rooms.

 Is this inspection Standard adequate to determine the proper operation of the HVAC equipment?

What does this Home Inspection Standard tell us about the home we are buying?

             It tells us what form of energy the HVAC system utilizes. This is commonly electric, natural gas, liquid petroleum gas and home heating oil.

             It tells us what type of HVAC system is installed. This is most commonly found to be forced air, hydronic or steam.

             The home inspector operates the HVAC equipment using the operating control which is most commonly a thermostat. The home inspector will hear components of the system starting and running. They will feel air movement or water movement through the distribution system. It is a common practice for a home inspector to measure the temperature of the fluid entering and leaving the system. This however is not a requirement of the Standards of Practice because it falls under the "analysis of system capacity" exclusion.

             Home Inspectors remove access panels (provided for the homeowner) which allows observation of filters and the front of the burner compartment of a gas furnace. There are numerous other components that are not visible from this location. Access panels which are required by the State Inspection Standard to be removed, do not require tools of any kind for removal/inspection.

             Operation of the HVAC equipment has limitations and exclusions: The Home Inspector is not required to operate the heating or cooling system if the weather conditions are outside of the operating parameters of the heating/cooling unit. In other words, air-conditioners are not operated in the winter and heaters are not required to be operated in the summer. Exactly what defines these seasonal operational parameters is determined by the home inspectors interpretation of what may cause "equipment damage". It is often a practice that air-conditioners are not operated below 60-65°F. This is believed to be derived from manufacturers recommendations. If the HVAC equipment is not a "central air conditioner/heater" inspection is not required. Performance of the equipment, which includes proper distribution of heating/cooling fluids does not require evaluation. Again, this is an evaluation of system design that is outside the scope of inspection. The equipment must only “respond” to the operating controls. It is not necessary for the equipment to perform to any degree of capacity other than provide a source of heating/cooling in each habitable room. It must have the "potential" to heat/cool each room, but actual performance is not required to be inspected/evaluated.

             As you can see, even from a layman's point of view there is a lot more to the heating and cooling system than is being inspected. So why is this?

            First of all it is a violation of the clean air act and Montréal Protocol for contractor who is not EPA Certified to potentially release ozone-depleting refrigerants into the atmosphere. In the state of Tennessee, a large portion of our heating equipment are heat pumps which contain ozone depleting refrigerants. Almost every house in Tennessee has an air conditioner.

             Second, a substantial amount of education is required to merely "understand" the operation of the HVAC equipment. This requires background in electrical (supply voltage and control circuits), plumbing and mechanical contracting. This is a totally separate business from Home Inspection. General contractors hire mechanical contractors to perform these installations because it is even beyond the scope of General Contracting.

             The bottom line is that Home Inspectors are "generalists". They are experts at being a Generalist, meaning they know a lot-a-bit about everything! They are trained and experienced in how things operate and how they are used for a specific purpose. They know the ramifications involved if systems are not properly utilized/installed. This is beyond the layperson’s common knowledge so it classifies them as an expert. They are collectors of information and formulate reports to help the home buyer better understand the product which they are purchasing. They are educators and observers, viewing the property as to how it affects the family dynamics of the potential buyer. They do all this with their hands tied behind their back! They are visitors to the property and cannot perform any activity which may potentially damage the property. They are governed by federal laws which mandate that they cannot perform the required inspections to accurately determine if the equipment is in fact operating properly. However, on the other hand they are expected to determine the functionality of the HVAC system by the home-buyer, who may pursue a claim against the Home Inspector when equipment failure occurs, utilizing a lawyer and the court system.

 Why do home-buyers claims stand up in a court of law?

 Often because the Home Inspector is playing Superman! Offering services which they can not perform. Laying claims to the ability of performing an inspection to a standard beyond which they are capable of. The expectations of the home-buyer is that a home inspector will provide the information they require to make an informed decision. When their expectations are not met, they seek out relief from their perceived damages (plus expenses and lawyer fees).

 This article is not intended to separate the Home Inspector totally from the HVAC evaluation, but to place it in perspective with that which can be delivered. It is of the utmost importance that the clients expectations be met. We must therefore focus on molding the clients expectations. Before we can do this we must understand what the Home Inspector can legitimately do. We must stick with the Standards of Practice and requirements of the home inspection set by state law. We should not try to present ourselves as being "bigger than life" in our marketing or conversations with the clients. A system to accurately test HVAC equipment needs to be developed for Home Inspectors which is "legitimate" in evaluation of the system's operation.

 By "legitimate", I am referring to the practices that are often taught in home inspection schools and passed around amongst Home Inspection Associations as to how Inspectors evaluate HVAC equipment.

 This practice is the "temperature split theory". In this theory, a system is alleged to be in proper operation when a certain temperature difference between the air entering the system and leaving the system has been achieved. We refer to this as the "20° temperature differential". It is purported that if air enters an HVAC system at a specific dry bulb temperature, it should come out 20° lower than it went in.

 Before we can refute whether this test is valid or not we must understand the substance that is being tested/measured, "standard air". Air is made up of many components which when combined, results in what we consider "standard air". Boyle's law states that a gas is equal to the sum of its properties. Air coming into HVAC equipment is not equal to air leaving the HVAC equipment. Numerous components change during the process. One of the components which we are discussing is the dry bulb temperature. Without understanding all the processes involved, one must only note one simple fact; more things change during the process than just the dry bulb temperature.

 We test dry bulb temperature with a "sensible heat thermometer". If testing light, we measure luminance. If testing sound, we measure decibels. Each testing device evaluates a specific component. In the evaluation of "conditioned air" the component we are trying to measure is "heat energy". Temperature measurement alone does not determine the amount of heat energy in a substance only it’s temperature. It is important not to use the word heat and temperature carelessly. Temperature is a measurement of molecular motion within the substance. The sensible heat thermometer measures "temperature" not "energy". Though this device can be used to derive "energy" levels, it does not directly measure "total energy" of air. So again without getting into all the psychometric properties of air, we can see that utilizing a testing device which measures "temperature" cannot be utilized to measure another substance, "energy". There is no single device to measure heat energy in the air "directly". A psychrometer is a test device which takes measurements with a thermometer and a hygrometer to mathematically determine "total heat (energy)".

 So why not just use a psychrometer?

Expense!

Is there a cheaper way?

Yes! It takes a thermometer, a small piece of cloth, a drop of water and a psychometric chart.

 There are so many HVAC systems being evaluated every day with just a dry bulb thermometer (thermostat) that it gives me goosebumps!

So many of my home inspector associates are being sued in court for HVAC equipment that failed after the home inspection!

So many home-buyers are disgruntled with their home inspection because of HVAC reasons.

Real estate agents who represent the buyer as well as the real estate agents representing the seller get drug into this scenario.

 There is really no reason for any of this!

So why does it reoccur daily?

Home inspectors are competing for home inspection jobs by offering HVAC inspections which they are really not qualified to do. Home-buyers are going to try to save money by having an inspection which should be performed by an HVAC expert conducted by their home inspector.

Real Estate Agents do not understand the difference between a Home Inspection and an HVAC contractor's inspection.

 An HVAC service call costs approximately $65-$75. HVAC service contracts cost a little bit more than this (for twice a year service). Evaluation cannot be adequately performed unless the unit has been serviced and cleaned first. Cleaning and servicing the equipment increases performance, efficiency and increases life expectancy of the equipment (a third benefit). An adequate diagnosis cannot be performed unless the system has been restored to its original factory condition.

 The HVAC system is the single most improperly installed equipment in a home.

The HVAC system is the most likely appliance to fail during ownership of the property.

The HVAC system is the single most costly appliance in the home to replace.

The HVAC system keeps you and your family comfortable!

 Contrary to popular belief, Home Warranties do not always cover the repair/replacement of failed HVAC equipment. There is a lot of fine print in these policies that exclude

 Expecting a home inspector to inspect your HVAC system is a shortcut to failure!

My point is not that the home inspector should not inspect the HVAC system, rather the buyer's expectations of the home inspector is way beyond that which the home inspector can provide.