Inverter Air-Conditioners

Like virtually EVERY version of an HVAC system, there is no "always" better type of system.

Inverter systems are TYPICALLY used in lieu of through-the-wall "central" systems, and are almost always higher efficiency because they can have larger condenser coils and often larger evaporator coils.

Because of that distinction, they are also often NOT optimized with respect to peak performance. Therefore, it is easier to find a "normal" split system with SEERs that are 25% to 40% or more higher than Inverter Units- BUT, you can likely also find Inverter Units with SEERs that are higher than the current 'standard" minimum values.

However, because the inverter style is basically a FULL room conditioning unit, it will likely cost MORE per ton than a central split-system unit designed to serve several rooms from a single air handler.

Good question. The motor/compressor is still run at a constant (optimum) speed and is turned on and off to modulate the amount of heating or cooling.

I've always assumed the inverter is used to limit the startup current surge or reduce starting noise. This may be useful in reducing cable sizes or office block switchboard sizes.

Of course, the COP varies a lot between different units but this isn't directly related to the inverter. FFEJ

Hello,

The best option is to install both the systems

Use them alternate day

Put data logger.

do it for full hot summer

This will offer you best comparison.

Regards

MRC

Unless you are good with electronics AND have a good "hands-on" understanding of HVAC... or have someone on staff that is ...the actual real world savings over the life of a variable speed unit could be ZERO because of the sensitivity to power fluctuations and cost of replacement parts. You must also consider the human factor. Few people allow variable speed units to operate as designed which defeats their purpose. At best your return on investment could be from 6 to 10 years.

As for the question about what an inverter system is read below.

wikipedia.org "inverter air conditioners"

"The unit continuously regulates its thermal transfer flow by altering the speed of the compressor in response to cooling demand. Inverter units use a variable-frequency drive to control the speed of the motor and thus the compressor."

forums.vr-zone.com "why-no-savings-inverter-air-conditioner"

GA to all. I have installed 19 seer inverter drive and standard 13 seer in like situations and found the current draw runs much lower with the inverter. The same is not true with standard equipment. We have found that the power consumption is almost the same with high seer and low seer equipment. Apparently ARI allows the manufacturers to self certify. They "overblow" the evaporator in the tests which allows more sensible but less latent heat removal. It's a cheap trick but it allows advertising a higher seer and using a smaller compressor and condenser coil saving money. The inverter saves energy on the start and allows the compressor to match the load.

We have a 75 ton that we converted to water cooled from air. The vfd's control pump speed to maintain 94' condening pressure. Lowered power consumption almost 30% but I would expect over 20% drop going from air to water cooled. We have a new vfd starter panel ready to install and need to program a new operating sequence. Big question is effect on compressor oil pressure when we lower speed. 'Trane' will not give any help but the 'ASI' programming software allows us to create logic to automatically revert to the pump speed septup if the oil pressure drops too low. The next obsticle would be defeating the suction unloaders when the inverter is controlling compressor speed.

Comments and criticism are always welcome, it's part of any productive process.