Many systems have a built-in delay that prevents immediate start after a power failure, even if the unit isn't running at the moment it happens. The delay typically is ~5 mins but may be longer depending on what may be programmed into the thermostat or a control board inside the unit.

I would recommend ‘Whole House Surge Protection’ installed at the Load Center (Breaker Panel) so that all 110v & 220v equipment has some protection from internal and external voltage spikes and fluctuations. Including all 220v electronically controlled stove tops, ovens, dryers etc.

During severe thunderstorms switching HVAC breakers ‘OFF’ at the main electrical panel (load centre) is the best protection as switching the system ‘OFF’ at the thermostat still leaves all the other components vulnerable, such as all electronic circuit boards, thermostats, ECM blower and ECM fan motor controls.

IMPO

SR

To your question,yes,it is definatly prudent to prevent compressor (any compressor) from going off then quickly re-starting. As someone mentioned,some units are factoy equipped with "time delay" and some are installed in the field. To more reliably protect compressor, I reccomed having tech check during seasonal maintenance to see if units already have delays and install some if not.

In order to fully protect a piece of equipment (any electrical equipment) from the likes of a possible near by lightning strike -- the path in which it is connected to your electric panel must be 'interrupted'.

If the appliance is a plugged appliance - pull the plug. TV's, computers, refrigerator, freezer etc (anything that is plugged in).

HVAC - shut off / pull disconnect / then shut off breaker to furnace (AC and furnace are on separate breakers).

Ideally the only thing that should be left on is lighting.

Most electric panels aren't marked, if yours is -- another way would be to go to the electric panel and shut off power from things there. Only if your house suffers a direct lightning strike would you suffer damage with circuit shut off but things still plugged in to wall outlet.

Under a direct hit the lightning will take the least resistance pathway to ground. In some cases that will probably cause damage to anything connected to your electric supply in your home.

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With that said doing this you only slightly reduce the chances of electrical damage.

Why? because voltage fluctuates on the grid. The grid operator is continually adjusting things and maintaining that grid so it functions normally. This is typically more of a challenge during electrical storms, but it also can be challenging under high load / heavy use events.

See Brown Outs / Power surges ----- these events happen all of the time.

Direct electric strikes are devastating, but they are relatively rare. Over the course of my career I've visited about 3 such homes that the damage was likely from a 'near by' lightning strike event.

The damage varies when it comes to HVAC. -- typically electronics are the most vulnerable.

mike_home nailed it. The real damage occurs to compressors and large motors is due to either trying to run or to start when the voltage is transiently (artificially) low. Another related concern is the power company's attempt to restore power improperly following a loss of power. The proper thing to do is find and correct the fault of the power loss before attempting to restore power. This to avoid causing damage. Power companies should have a protocol regarding power restoration, however they frequently do not or can not follow it.

Yes, turn off or otherwise remove power to your A/C... and I'd suggest unplugging sensitive electronic equipment for the same reasons.

As pointed out above, you are not trying to protect from a direct lightning strike - your homeowners insurance does that! lol

Wow, thanks for all the information and perspective. In many forums I'm lucky to get a one sentence reply. Much appreciated!