7 min read · updated 2026-08-05
Preventive versus reactive maintenance
What preventive maintenance actually prevents, what it does not, and how to decide which systems in your building justify a PM program.
Written for facilities directors deciding where a maintenance budget goes.
What is the difference between preventive and reactive maintenance?
Preventive maintenance is scheduled work performed before failure on a set interval; reactive maintenance is work performed after something has already stopped working.
Most buildings run a blend and should. The question is never whether to do preventive maintenance, it is which systems justify it, because a PM program applied to everything costs more than it saves.
Does preventive maintenance actually save money?
It saves money on the specific failure modes it inspects for, and it does not prevent equipment from reaching the end of its life.
This distinction gets sold badly and it is worth being precise about. Coil cleaning, filter changes, belt inspection, condensate clearing and charge verification all prevent failures that are genuinely preventable. None of them stop a twenty-year-old compressor from failing in year twenty-one.
A vendor promising that preventive maintenance will eliminate emergency calls is selling something. What it does is move a meaningful share of your failures from unplanned and expensive to planned and cheaper, and it produces the service history that makes the eventual repair-or-replace decision something other than a guess.
Which systems justify a preventive program?
Prioritise systems where failure is expensive, disruptive or dangerous, and where the failure mode is genuinely predictable.
| System | PM priority | Why |
|---|---|---|
| HVAC | High | Highest failure cost, most predictable failure modes, worst timing on the Gulf Coast |
| Elevators | High | Tenant-visible, compliance-driven, entrapment risk |
| Life safety and emergency lighting | High | Testing is a requirement, not an option |
| Roof | High | Cheap inspection, extremely expensive failure, damage is cumulative |
| Electrical distribution | Medium | Thermal scanning catches real problems, but interval can be long |
| Plumbing | Medium | Mostly reactive, except where a failure floods occupied space |
| Interior finishes | Low | Condition-based. Inspect and schedule, do not PM |
How often should commercial HVAC be serviced on the Gulf Coast?
Two full preventive visits a year is the working minimum for Gulf Coast commercial equipment, with filter service on a shorter interval set by filter type and the building's dust load.
The reasoning is climate. A rooftop unit in this region carries a cooling load close to nine months a year, so equipment accumulates run hours far faster than a national maintenance interval assumes.
Restaurants, labs, manufacturing and any space with high particulate load generally need quarterly. So does any building where a failure means closing.
What does a real PM visit produce?
A preventive maintenance visit that leaves no written record is indistinguishable from a visit that did not happen, and the record is most of the value you are buying.
- Per-unit record
What was inspected, what was found, what was corrected, per piece of equipment rather than per building.
- Readings over time
Pressures, temperatures, amp draws. One reading is data; a trend line is a warning.
- Deficiency list
What was found and not corrected, with a recommendation and a cost.
- Equipment inventory
Make, model, serial, install date and location. Most buildings do not have this and every capital decision needs it.
- Photographs
Before and after on anything that was corrected.
Questions we actually get asked
How much of a maintenance budget should be preventive?
There is no correct ratio, and any figure quoted as a rule is borrowed from manufacturing rather than from commercial real estate. The practical test is whether your emergency call volume falls in the systems you are running PM on. If it does not after a year, the program is being performed on paper.
Is preventive maintenance worth it on old equipment?
Yes, but the goal changes. On equipment near end of life, PM is buying you a planned replacement instead of an unplanned one, which is worth a great deal on a system whose failure closes a floor.
Related
Also worth reading before you sign anything
Next step
Tired of poorly maintained facilities?
That was the best line on the old website and it sat halfway down the homepage under a generic button. Tell us what building you are running and what is not getting done.