As a curious lighting kid of the 1970's, at a local shopping mall one of the poles was taken down. It was a round 5 foot ball. The center of the ball perimeter it has small circles maybe half inch diameter in a row circling the perimeter at the widest part of the ball fixture. There were 4 cutouts at 45 degree angles downward,  the openings and reflectors may have been for 4 400 watt mercury vapor bulbs, or bigger. It was fascinating to see inside looking thru the small perimeter holes. There was only 1 of these poles with this fixture.  It sat along the mall wall for a few months than vanished. The remainder of the mall was lit with double davit steel streetlight poles with fluorescent fixtures. The mall opened in 1959. Has anyone seen one of these space age round fixtures?

Reduced flow and pressure delta is how the mechanical power is reduced, but how do the mechanical losses behave under those varying conditions ? Are they linear, quadratic, something else ?

2023=G
2024=M
2025 (potentially) = Q

Inverter setup allows the use of more efficient motor designs (lower slip and/or even permanet magnet synchronous) that become harder or even impossible to start on a fixed frequency AC feed, so either can not be used at all without the inverter or need rather complicated starter system that is nearly as complex as the inverter.

Inverter designs do not lock the exact rpm, so there is another "knob" available for the system design allowing better optimization.

And mainly the biggest difference is related to the losses related to the second law of thermodynamics and temperature differences on the two main heat exchangers: The condenser vs ambient air and the evaporator vs the home air.
Inverter system (or any system able to vary rhe compressor power while maintaining its efficiency) reduces the power to maintain the target temperature. That means those two heat exchangers have to be transfering less power, but they remain of the same size, so the same thermal resistance (now simplifying a bit, as in reality the blowers are also throttled down). Less power on the same thermal resistance means condenser condensing the refrigerant at lower temperature so lower pressure. At the same time the evaporator gets warmer, so creating higher pressure vapor. Both of these means there is less pressure differential for the compressor to fight, hence less power demand to run it.

Is your state doing any fluorescent/incandescent bulb bans like Colorado has?  We still can purchase HID but CFL/Fluorescent and most incandescent bulbs are banned with only a few specialty allowed.

Hmm…seems like a trip to my local store may be in order. I really hope that Lowe’s isn’t getting rid of everything fluorescent. T12 lamps, I could understand. Manufacturers are making them so cheap these days that it’s not even really worth it to buy the new ones. But F32T8 lamps for instance are still widely used and I think the current production ones are still pretty good quality.

This really is pretty basic stuff and should be obvious

And also is wrong

Once steady state is achieved (the condition in which the inverter unit winds down), the air conditioning unit output, averaged over time, equals the heat loss (or gain, if we are in the summer) through the room walls. This heat loss depends linearly and exclusively on the temperature difference between the room (chosen by the user) and outside (determined by the weather), and insulation resistance of the room walls

The air conditioning unit has no effect on the heat loss. In case of an on/off switching unit, the hysteresis beween the on and off temperatures is way less than the temperature difference between indoors and outdoors, so in average it still has no effect on the heat loss

The air conditioning unit then must pump the same quantity of heat/time unit in or out to maintain the temperature difference constant. Heat is energy, heat per time unit is power

Consider 2 compressors with identical COP but different power. One is of the exact power required to counter the heat loss, and the other is 2x the power. The 1x one will work continuously, the 2x one will work with 50% duty cycle. Twice the power for half the time is the exact same energy

So no, thermodynamics absolutely don't confirm this basic stuff



Now let's look at the electrics :

The on/off unit has a simple induction motor. There is no principal limit on the efficiency of such motor. Having to work only in a single set of conditions (same power, same refrigerant pressures, ...) it seems obvious to optimize this motor for working at this exact set of conditions

Limiting the efficiency of such motor is only cost - If using a bigger motor with room for thicker winding, Using lowloss steel in the laminations, etc. The motor can be made to any desired efficiency

The inverter unit has a similar induction motor. It is basically a plain 3 phase motor, though most of them are not for 50/60 Hz but for somewhat higher frequency

Higher frequency allows for smaller cores and less turns in each winding (which means thicker wire can be used in the same motor size), same as in lighting ballasts. However, there are few parts that can pull efficiency down as well :

 - The stator is still made of laminations, which dont behave well above few 100s Hz. (Eddy currents, hysteresis losses, increasing loss in general)

 - The motor must work efficiently in a broad range of speeds and pressures. Is it optimised for the exact ones at which it'll run in your case ?

 - The inverter itself also got losses

Considering that 50/60Hz induction motor efficiency is typically 85%..90%, this gives the theoretical upper limit of energy you might save if the inveter and inverter powered motor would be 100% efficient

In reality, the motor is probably closer to the same 85..90% as the other motor, and the inverter has a few % left behind as well



And at the mechanics :

Running at higher speed (due to higher RPM motor) allows pumping the gas faster, or at the original speed but with smaller pistons

Smaller pistons and all the other mechanical bits have less friction surface, however they work faster for the same output, so the friction loss happens more times

Similar considerations would apply to other compressor types as well (Scroll, vane, etc)

I am not sure how the less surface vs. faster running exactly balance vs each other

Same as with the electrics, the mechanics are the same in principle and only differ in size. Both have losses of the same order of magnitude



At this point, it is no longer about any significant energy savings, but other things :

 - Cost cutting. We have reached the point where a complete inverter circuit cost is cancelled out by the savings on smaller and cheaper motor and mechanics which have to work faster. (And question remains whether the mechanics will last as long as the bigger slower running ones)

 - Blatant shoving of advanced technology everywhere it is not needed

That’s what I’m wondering as well. There aren’t any others nearby to check, but I had thought I heard at other stores they weren’t on clearance.

I remember they clearanced them in the past when switched from the Sylvania brand to GE, but that doesn’t seem to be what’s happening this time, and then it was all bulbs.

Yeahhh!

Yeah haha, gone now.l sadly.