Why Home Inspectors May Not Test Your A/C in the Fall
Wondering why your A/C wasn't tested during a fall home inspection? Learn why low outdoor temperatures can prevent inspectors from operating the system and what buyers should know.
9/23/20262 min read
What happens when outside temperatures drop below 65°F?
If you're buying or selling a home during the fall, you may notice something unexpected during the home inspection: the air conditioner isn't turned on.
That doesn't necessarily mean the inspector overlooked it.
When outdoor temperatures are too low, operating a conventional central air-conditioning system can potentially damage components of the system. For this reason, home inspectors generally follow temperature restrictions when testing cooling equipment.
Why does temperature matter?
A central air-conditioning system relies on a refrigeration cycle involving the compressor, condenser coil, evaporator coil, and refrigerant.
When outdoor temperatures are sufficiently warm, the system can operate within the conditions for which it was designed. But when the outdoor temperature drops, operating the system may create conditions that are not appropriate for normal cooling operation.
One concern is the behavior of refrigerant and compressor oil at low temperatures. Under certain conditions, liquid refrigerant can migrate toward the compressor. Because the compressor is designed to compress refrigerant vapor rather than liquid, starting the system under unsuitable conditions can create a risk of compressor damage.
That's why the 65°F guideline is commonly used by home inspectors when determining whether a conventional A/C system should be operated during an inspection. InterNACHI's home inspection training materials specifically identify 65°F as the outdoor-temperature restriction for operating air-conditioning equipment.
What does this mean for a fall home inspection?
If the inspection takes place on a cool fall day, the inspector may:
Visually inspect the accessible components of the cooling system
Inspect the exterior condenser and accessible refrigerant lines
Document the outdoor temperature
Report that the cooling system was not operated because of low outdoor temperatures
The inspector should not simply turn on the system to see whether it runs if doing so could potentially damage the equipment.
Does this mean the A/C is broken?
No.
An A/C system that isn't operated during a fall inspection has not necessarily failed.
It simply means that its cooling performance could not be fully evaluated under the conditions present on the day of the inspection.
If the cooling system is important to the buyer, a qualified HVAC professional can evaluate the system when outdoor conditions are appropriate for testing.
Buying a home in the fall?
This is something buyers should understand before the inspection.
A fall or winter inspection can provide valuable information about many components of a home, but seasonal conditions can limit the operation of certain systems. The same principle applies to other inspection limitations caused by weather or environmental conditions.
At Clear Point Home Inspections, we document these limitations in the inspection report so buyers understand what was inspected, what was not operated, and why.
Buying or selling a home in Chicagoland?
Schedule your home inspection online with Clear Point Home Inspections.
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Thank you for visiting Clear Point Home Inspections LLC. We provide thorough inspection services for residential and commercial clients throughout the greater Chicagoland area. If you've been searching for a trustworthy and knowledgeable certified home inspector, you,ve come to the right place.
