??? Good/bad or? This is for a 6000 sqft/ac ICF house with Low E windows in South Florida (10 miles in from the coast). Thanks!

They don't have a terrifically large footprint yet.
All equipment is headed in this direction though.

Don't know about the specific NORDYNE (several brands) IQ Drive models but I'd be more concerned about the HVAC contractor if considering such an expensive unit. Expect sticker stock if your goal is saving money rather than comfort. The real advantage of inverter ACs in general is that their compressor speed can be adjusted (with little loss in efficiency) according to temperature and humidity.

The goal is save money long term without sacrificing comfort. How bad you think it will be?

Posted By ErVikingo on 30 Apr 2012 09:07 AM
How bad you think it will be?

Only a qualified contractor in your area can tell you that. If you have more general questions, HVAC-Talk (they're not allowed to post prices) would be a good place on the internet to ask.

Thanks!

Posted By ErVikingo on 30 Apr 2012 09:07 AM
The goal is save money long term without sacrificing comfort. How bad you think it will be?

What are we comparing it to? Compared to 16-18 seer equipment it may only be 25% more. Compared to 13 seer equipment it could be 50% more.

Thanks Joe!

I gather premium over current state of the art (19 seer?). 25% is not much in the scheme of things. I am more concerned with quality and life expectancy.

Some old and new sites for conversations that may be helpful to you; and just calling Bristol Compressor in VA can lead to technicians inputs that cover 5+ years (like other manufacturers too).

http://www.westinghousehvac.com/Westinghouse-iQ-Drive-174-Air-Conditioner-p/fs4bi.htm

http://hvacrdistributionbusiness.com/hvacr_issue_20110901/

http://iqdrive.net/pdfs/Inverter_Reprint_FINAL.pdf 2009

vs systems with dual compressors that you may find below 30% as a first-ouput low-compressor size may fit
or
dual compressor combo units that are with having one  IQ drive compressor

Very good reliability, still.
Motors of modulated IQ Ver Rfg drive is 'older' motor technology, "near" complete load matching. That motor technology is just not relatively new at all.
Soft starts, contactors cycling less, like with water pumps ? ~ 20 years now in the US: Veriable drive by temp and press,  and PWM signals, as well.

 ? kinda related:
Ask a radio/control R/C modeler what "brushless" DC variable motor control/efficiencies did many years ago for that industry. (phase-inverted-not-needed per the a.c. electricity).
pwm since the 70's .