Individual Best Practice

by Nate Hunter

HVAC preventive maintenance inspections (PMIs) are a good way to save on repair and maintenance costs.

Challenge: Based on customer feedback, and years of benchmarking, it is our recommendation that at the time of a Preventive Maintenance Inspection (PMI), certain repairs, part replacements and cleanings should be performed on an “as needed, time-and-material basis,” and not incorporated into the PMI flat fee price per store per PMI. Any such extra work would be billed on a separate invoice, and tagged as PMA (Preventive Maintenance Authority).

Best Practice


Condenser coils

There are several reasons to consider performing condenser coil cleanings on a time-and-material, as-needed basis (versus having the cost of it included in the PMI budget), which in most situations can be performed during a scheduled PMI:

1. Some condenser coils can easily go 2 years, and sometimes longer, before needing to be cleaned.

2. In many instances the coil(s) may not require a cleaning during a specific scheduled inspection, but may require cleaning before the next scheduled inspection (i.e., due to the shedding of cottonwood trees in some regions of the country, busy highways nearby, etc). Why pay for a coil cleaning that was not really needed only to have the procedure repeated again within a brief period of time?

3. Some units may require more than one cleaning annually, depending on the area and other variables.

4. Some units have double coils that require taking the unit apart — at an increased labor cost — in order to separate the coils so that they may be cleaned properly. The retailers either pay more than they should when coil cleanings are priced into the inspection or they do not get as thorough of a cleaning because the contractor priced the service low to get the business and then took shortcuts in order to protect his profit margin.


Evaporator Coils

Unlike condenser coils, evaporator coils, which are commonly much more costly (labor intensive) to properly clean due to their location, typically do not need to be cleaned as often, primarily because the air blowing over the coil is filtered.

Evaporator coils can easily go as many as 5 (or more) years before requiring cleaning, and if these coils get dirty before their time, it is due to the following reasons:

1. Improperly sized filters, which allow dirt to blow by them, collecting on coil surfaces.

2. Irregular filter changes (not enough and or missed inspections).

3. Units that introduce outside air into the air stream — whether an economizer or manual outside air damper — where the filters are located in the store (in return air filter grills) versus inside of the unit between the evaporator coil and the outside air intake. (Units with outside air intakes must have filters installed in the unit because the filters utilized for the outside air intakes are only designed to keep out large particulates, rodents and birds.)

Note: Do not allow filters to be installed inside of the HVAC unit and inside in the return air filter grills. HVAC systems are not designed to overcome the resistance created by two sets of filters.


Blower wheels

Need to be cleaned about as often as the evaporator coil (see above), except when the blower wheel is located upstream from the air-side filters, in which case you may be looking at cleaning them during every other condenser coil cleaning cycle.



Typically, it is a good idea to only replace belts that appear worn beyond their use. If your contractors are pricing annual belt replacements into their PMI bids, you may be paying for belts that you really did not need to replace. Depending on the grade of belt and other factors, their life expectancy can extend well beyond 1 year. We suggest replacing them, as needed, on a time-and-material basis. This is typically performed during a scheduled maintenance, but only as needed.


In order to take advantage of substantial savings, we suggest allowing the servicing technician the latitude to perform only those repairs and cleanings needed, up to a not to exceed dollar limit, during the time of a PMI (most retailers use an average of $250 to $800 per visit). This results in a savings on labor for travel and setup time (the technician is already at the service location), and the contractor is not taking shortcuts because he may have under priced the inspections; consequently, the job is performed correctly.


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