Guide to Inspecting Central Heating Systems

We understand assessing a home's central heating system as a fundamental part of the home inspection process. The American Society of Home Inspectors (ASHI) sets clear standards for this part of the inspection, and understanding these standards is crucial for homeowners, sellers and real estate professionals for both negotiation power and safety.

The life expectancy of heating systems varies - gas/LP furnaces last around 15 years and cast iron boilers over 35 years. Regular and professional servicing plays a crucial role in extending a system's lifespan.

ASHI defines a "readily openable access panel" as one that is easily accessible, within normal reach, can be removed by one person, and is not sealed in place. This guideline is pivotal in performing a visual inspection of a home's heating system.

The inspection involves removing the manufacturer-supplied front panel for a visual check of the system's components during operation. The inspector operates the heating system using standard controls and notes its basic functionality. Any abnormal sounds or operation issues are recorded.

The inspector identifies the type of heating system and its fuel source. It’s imperative the inspector differentiates between systems like furnaces, boilers, and heat pumps, as they function differently. The inspector also examines the exterior of any visible ductwork or plumbing as well as all living spaces for a permanent heat source. Supply temperatures from various systems are noted, the standard sitting around 90° F to 110° F for furnaces and heat pumps and 160 to 190° F for boilers. The inspector assesses the heating system’s exhaust method including the pitch and condition of exhaust pipes and chimney connections.

Problems like improperly pitched exhaust pipes, holes, water staining, and inadequate chimney connections are flagged. In shared flue situations, proper connection order based on British Thermal Unit (BTU) ratings is crucial for safety.

The visible exterior portions of the chimney are inspected, but most of its structure is not accessible during a standard home inspection. We often recommend a certified chimney professional for a comprehensive check.

While many aspects of the central heating system are checked, there are some areas that fall outside the scope of the inspection or some cases that inhibit the inspector's ability to complete the inspection fully. For example, heat exchangers and efficiency measurements are outside the scope of a standard inspection. In addition, the inspector does not assess the sizing or balance of HVAC ductwork nor the make-up air requirements. Moreover, specialized systems like humidifiers, dehumidifiers and solar heating are also excluded from the inspection.

The inspector requires clear access to the heating system, if the system is not easily accessible, then it can’t be inspected properly. Also, heat pumps are not tested in heat mode if the exterior temperature is above 60° F to avoid damage. Any limitations to the inspection are noted in the report with recommendations for ensuring proper operation before closing.

As of January 1, 2020, the import and manufacture of R-22 (Freon) are prohibited in the U.S. Older systems using R-22 may require costly recharges, making new system installations more cost-effective. Newer refrigerants are now entering the market, replacing older types like R-410A (Puron).

As home inspectors, our role is to provide a detailed and thorough evaluation of a home's heating system, ensuring it operates efficiently and safely. Regular maintenance and understanding the specifics of your heating system can significantly impact the longevity and performance of the system. Remember, a well-maintained heating system not only ensures comfort, but also contributes to the overall value and safety of your home.

Author Bio:

Josh Rogers

As a former professional home inspector and Training Specialist at WIN Home Inspection, Josh has years of experience in both performing and teaching home inspections, infrared scans, radon testing, mold testing, and more.