Dirty electricity, defined as erratic spikes and surges of electrical energy traveling along power lines and building wiring where only standard 50/60-Hertz AC electricity should be, can be caused by several different types of anomalies. It can be power spikes and surges, or excessive line noise. Other causes involve low power, voltage sag and noise harmonics, which can have an effect on HVAC equipment in some instances.
Most of today’s standard HVAC systems are not truly affected by “dirty electricity”. The higher efficiency communicating systems, however, can be affected. There can be issues when you go from standard relays and contactors to the communicating circuit boards that involve computer software, that monitor input voltage, voltage drop, excessive voltage, etc.
Line noise and harmonics are usually prevented in most cases by either a ferrite core or a capacitor, which will block out low frequencies and the inductor which will block out high frequencies. The equipment manufacturers have made changes in the higher efficiency equipment to compensate for these type of issues that can popup anywhere from time to time.
Some small portable generators have also been known to cause “dirty power”, but all in all, the industry has a pretty good handle on this widespread issue, and made important strides to improve and protect our equipment.