When inspecting a home’s central heating system, the Standards of Practice of ASHI (American Society of Home Inspectors) requires the home inspector to open “readily openable access panels” to perform the visual inspection. One may ask, so what is a “readily openable access panel”? ASHI defines this as: “A panel provided for homeowner inspection and maintenance that is readily accessible, within normal reach, can be removed by one person, and is not sealed in place”.
This does not mean that the inspector takes the heating system components apart to perform an invasive inspection or a clean and service, but rather removes the front panel that the manufacturer has supplied to perform a visual inspection of the visible components while the system operates. The inspector will operate the central heating system (such as a furnace, boiler, or heat pump) using its normal operating controls (meaning the thermostat) and observe the system's function. In some older heating systems, more of the combustion process may be visible compared to newer heating equipment. Should abnormal sounds or anything out of the ordinary be observed with the system’s operation, these will be reported by the inspector.
ASHI requires that the inspector report the type of heating system (furnace, boiler, heat pump, electric baseboard, etc.) and fuel source (natural gas, fuel oil, propane, electric, etc.). Keep in mind that a furnace, baseboard heater, and heat pump all heat air, whereas a boiler heats water which then heats the home. Many people often get the terms “furnace” and “boiler” confused and use the terms interchangeably when they are actually very different systems.
A newly installed gas-fired forced warm air furnace.
While running the heating system, the inspector should verify that all living spaces are being supplied with heat. Finished living areas of the home that are not heated should be noted in the home inspection report. The supply temperatures from a furnace and heat pump (in heat mode) will normally be in the 90° F to 110° F range. The radiator or convector temperatures of a hot water boiler may reach 170~190° F; a steam boiler, even higher.
The ASHI Standards also require the inspector to inspect the heating system’s exhaust method, such as an exhaust pipe’s chimney connection or PVC venting. Heat pumps and electric baseboard units have no exhaust as neither uses a fossil fuel source.
Common issues that are found during the home inspection will include improperly pitched exhaust pipes, metal exhaust pipes that have holes or evidence of water staining, and inadequate chimney connections. The exhaust venting should be properly pitched upwards to ensure proper draft and be adequately sealed into the chimney, such as with furnace cement. Water staining on metal exhaust pipes often indicates moisture condensation within the flue or the lack of a proper flue cap allowing rainfall down the chimney. Both issues should be addressed by a qualified HVAC technician to ensure the proper drafting of exhaust gases out of the home.
When a water heater and furnace both share a chimney flue, for example, building standards require that the water heater’s vent enters the chimney above the furnace’s vent. Technically, the lower BTU (British Thermal Unit) rated appliance’s vent should enter the chimney above the higher BTU rated appliance’s vent. In most cases, a water heater will be a lower BTU appliance than a boiler or furnace. An improper flue connection can prevent proper drafting of appliance’s exhaust gases out of the home and may allow carbon monoxide, for example, to fill the home. Keep in mind that a home inspection is NOT a code compliance inspection, but a prudent home inspector should be familiar with the various building codes.
While ASHI does require the inspector to inspect the chimney (if applicable), as part of the inspection, the inspector is inspecting the chimney’s exterior that can be viewed either from the ground, gutter level, or from the roof. Most of the chimney (where the home and chimney meet as well as the chimney’s interior) are not visually accessible and are, of course, excluded from a home inspection.
I routinely recommend to my clients that a qualified chimney professional be consulted to perform a Level 2 Clean/Service, simply because there are areas of the chimney that I simply can’t see. A Level 2 Clean/Service entails a qualified chimney professional initially cleaning the chimney’s interior and then using either still or video photography to thoroughly inspect the chimney’s interior and exterior for defects. A blocked or otherwise compromised chimney can present an immediate safety hazard to the home’s occupants. A complex chimney repair can be quite expensive, so heeding the inspector’s recommendation for a thorough chimney inspection now can save the home buyer countless dollars and headaches later. Ignoring the inspector's recommendation may leave the home buyer stuck with a huge repair bill should hidden issues exist but not be found until well in the future.
The ASHI Standards specifically exclude heat exchangers from the home inspection since they are most often out of view even when the front access panel is removed from a furnace or boiler. Also, the inspector does not perform efficiency measurements or determine whether the size of the heating system or its ductwork are balanced or adequate for the home. Doing so requires complex measurements and calculations that are best left up to an HVAC professional.
Also, excluded in the ASHI Standards of Practice are inspecting humidifiers, dehumidifiers, electronic air filters, solar heating systems, or the large storage tank systems (such as the Hydrokinetix units).
In some situations, however, the home inspector may not be able to fully inspect the heating system. One example is when stored items physically block access to the heating system. Home inspectors do not move the seller’s belongings, furniture, shelving, etc. to perform the inspection. All systems must be readily and safely accessible and fully operational for inspection.
This heat pump compressor looks (and works) very much like a stand-alone air conditioner system, other than heat pumps will cool and heat the home.
If the home has a heat pump system and the exterior temperature is higher than 60° F, running the heat pump in heat mode could actually damage the system. This temperature can vary by system manufacturer, but most inspectors use some temperature between 60° F and 65° F as their cutoff for running heat pumps and air conditioners. Most heat pump systems have a backup heating source, however, which can most often be tested at any temperature. If the home inspector can’t fully inspect a heating system (for any reason), the inspector should note this fact and the reason in the report as well as recommend ensuring proper operation prior to the home’s closing, should conditions permit. Also, all central heating systems should be cleaned/serviced by a qualified HVAC professional (annually is recommended) to help ensure efficient and safe operation. The inspector will verify whether there are recent (within the past 12 months) service records for the heating system available as well. A seller being able to provide documentation that the home's heating and cooling systems have been regularly (annually) professionally serviced goes a long way in buyer confidence of their next big investment, their new home.
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© 2014 Matthew Steger
Matthew Steger, owner/inspector of WIN Home Inspection, is a Certified Level 1 Infrared Thermographer, an ASHI Certified Inspector (ACI), an electrical engineer, and a US Dept. of Energy Home Energy Score Assessor. He can be reached at: 717-361-9467 or firstname.lastname@example.org.
WIN Home Inspection has provided a wide array of home inspection services in the Lancaster, PA area since 2002. This article was authored by Matthew Steger, ACI - owner of WIN Home Inspection in Lancaster, PA. No article, or portion thereof, may be reproduced or copied without prior written consent of Matthew Steger.