HVAC Inspections: Ensuring Your Comfort and Protecting Your Investment

Your home’s heating, ventilation, and air-conditioning (HVAC) system keeps you comfortable year-round — and it’s one of the most important systems we evaluate during a residential inspection. Below is a clear, practical guide to what we inspect on a typical home inspection in Ohio, the common defects we encounter, and what those findings mean for buyers and sellers. The procedures below follow InterNACHI’s Standards of Practice and Ohio’s licensed home-inspector Standards of Practice.

Scope — what an HVAC inspection covers (and what it doesn’t)

During a home inspection we perform a non-invasive, visual and operational evaluation of the readily accessible HVAC components. Typical items included:

• Identify and describe heating and cooling equipment (furnace type, heat pump, A/C condensing unit, boiler, etc.).

• Operate systems using normal operating controls (heat, cool, fans, thermostats) to confirm basic function.

• Inspect visible components: air handler/furnace, condensers, flues/venting, combustion appliances, access and clearances, filters, visible ductwork, registers, condensate drains and drip pans, electrical disconnects and service to HVAC equipment, and visible refrigerant lines at exterior units.

• Note safety issues (improper venting, cracked heat exchangers if detectable without disassembly, gas leaks, unsafe clearances, missing electrical disconnects, no secondary pan/drain, etc.).

Important limitations (per InterNACHI and Ohio SOPs): inspectors do not perform destructive testing, disassemble equipment, calculate equipment capacity or efficiency, verify refrigerant charge or combustion efficiency, or perform repairs. A home inspection is a snapshot of observable conditions on the day of inspection, not a guarantee of future performance.

Typical HVAC inspection checklist (what Mook Home Inspections looks at)

Exterior (condensing units / heat pump):

• Unit is level and on a stable pad

• Condenser fan/coil is free of heavy debris and obvious damage

• Refrigerant lines are insulated and secured

• Electrical disconnect present and properly labeled

• Unit runs when called from thermostat (if power is available)

Interior (furnace/air handler / boiler):

• Equipment identification (make/model/approx. age if visible)

• Combustion appliance venting (proper draft, no corrosion/large gaps)

• Combustion air / clearances adequate and accessible panels secured

• Burner assembly observation (no heavy sooting, visible rust)

• Heat exchanger inspection for obvious cracks/corrosion (visual only)

• Filters present and accessible; note condition/type and when replaced

• Blower operation, unusual noise or vibration

• Electrical connections, service disconnect and fusing

• Presence of secondary condensate pan, and drain termination

• Thermostat operation, location and obvious calibration issues

Ductwork / distribution:

• Major visible ducts checked for disconnections, heavy damage, significant sagging, or obvious mold/contamination

• Registers and grills: condition and airflow observation (qualitative)

Safety items:

• Gas piping to appliance: visible leaks or improper materials (visual only)

• Presence of carbon monoxide/combustion safety devices recommended if fuel appliances present

• Combustion vent terminations clear of obstructions and properly routed

Common defects we find — what they look like and why they matter

1. Dirty or missing air filters

   
   

   • Why it matters: Restricted airflow reduces comfort, increases energy use, and stresses blower motors and heat exchangers.

   • Typical fix: Replace with correct-size filter; recommend routine replacement every 1–3 months depending on filter type and house conditions.

     
     

2. Inadequate condensate drainage / clogged drain

   
   

   • Why it matters: Water overflow can cause interior water damage, mold growth, and electrical hazards.

   • Typical fix: Clear/repair condensate drain; install secondary pan/float switch if none present.

     
     

3. Improper venting / deteriorated flue (fuel-burning appliances)

   
   

   • Why it matters: Poor venting can allow combustion gases (including carbon monoxide) to enter living spaces — a significant health/safety risk.

   • Typical fix: Evaluate by an HVAC or combustion-safety specialist; repair/replace flue pipes or chimney liners as required.

     
     

4. Inoperative or intermittent cooling/heating

   
   

   • Why it matters: Indicates component failure (compressor, control, ignition, limit switches), low refrigerant, or electrical problems.

   • Typical fix: Diagnostic service by a licensed HVAC technician; may require parts or refrigerant recovery/charge (not performed by a home inspector).

     
     

5. Refrigerant line problems: insulation missing or damaged

   
   

   • Why it matters: Exposed lines lead to reduced efficiency and potential icing; also a sign the unit hasn’t been properly serviced.

   • Typical fix: Replace insulation on suction line; licensed tech to check system.

     
     

6. No or improper electrical disconnect / unsafe wiring

   
   

   • Why it matters: Service disconnect missing or improperly wired is a code and safety concern — hazardous for service personnel and equipment.

   • Typical fix: Licensed electrician/HVAC tech to install proper disconnect and correct wiring.

     
     

7. Obstructed outdoor unit or poor clearances

   
   

   • Why it matters: Blocks airflow, increases energy use, shortens equipment life.

   • Typical fix: Trim vegetation, relocate obstructions, ensure minimum clearance as manufacturer recommends.

     
     

8. Duct leaks, disconnected ducts, or significant gaps in boots

   
   

   • Why it matters: Reduces heating/cooling distribution and increases energy costs; may draw unconditioned air or contaminants into the system.

   • Typical fix: Seal and reconnect ducts using mastic or UL-listed metal tape; consider professional duct sealing or re-inspection.

     
     

9. Cracked heat exchanger (visual signs) or heavy corrosion

   
   

   • Why it matters: Potential combustion gas leakage into conditioned air — serious health risk. Visual signs (severe corrosion, heavy rust, or visible cracks) result in recommendation for immediate HVAC specialist evaluation.

   • Typical fix: Usually requires replacement of furnace or heat-exchanger assembly; specialist diagnosis required.

     
     

10. Aging equipment / near end of life

Why it matters: Older equipment breaks down more frequently and is less efficient. While inspectors don’t calculate remaining life precisely, we’ll note age and recommend further evaluation or budgeting for replacement.

When we recommend further testing or specialists

Per InterNACHI and Ohio standards, our inspection is limited to visual and basic operational checks. If we encounter any of the following, we’ll recommend a licensed specialist or further diagnostic testing:

• Suspected cracked heat exchanger, active gas leaks, or concerning combustion issues.

• Refrigerant concerns (leak, low charge) — requires licensed HVAC tech with refrigerant recovery equipment.

• Complex ductwork, mold contamination, or concerns about indoor air quality — refer to HVAC contractor, mold professional, or IAQ specialist.

• Any safety hazard (exposed live wiring, missing disconnect, unsafe venting) — immediate correction by the appropriate tradesperson is advised.

Notes on compliance: InterNACHI & Ohio Standards of Practice

• InterNACHI Standards of Practice define what a home inspection includes, emphasize the non-invasive, visual nature of an inspection, and instruct inspectors to identify and report material defects while avoiding invasive procedures (no disassembly, no performance calculations, etc.). We follow these conventions in every inspection.

• Ohio Administrative Code — Standards of Practice (OAC Rule 1301:17-1-17) governs licensed home inspectors in Ohio; it requires compliance with the state’s rules and outlines the inspector’s responsibilities, including unbiased reporting and limitation of scope to observable conditions. As a licensed Ohio firm, Mook Home Inspections follows these regulations.

Practical tips for buyers, sellers, and homeowners

• Buyers: Ask for recent service records and a manufacturer’s manual if available. If the inspection notes major HVAC concerns, obtain a written estimate from a licensed HVAC contractor before closing.

• Sellers: Replace/clean filters, clear vegetation from exterior units, and make sure access panels are secured — inexpensive steps that improve buyer perception. Disclose known issues and provide service receipts.

• Homeowners: Schedule regular preventive service (annual furnace and A/C tune-ups), replace filters regularly, and watch for signs: unusual odors, soot, banging noises, water leaks, or cycling issues.

Closing / Mook Home Inspections LLC approach

At Mook Home Inspections LLC we combine the InterNACHI best-practice approach with Ohio’s licensing standards to deliver clear, defensible HVAC observations and recommendations. Our goal is to identify visible defects, explain their implications, and point you toward sensible next steps — whether that’s a routine service call, a safety correction, or budgeting for an eventual replacement.