Mitsubishi M-Series New FH vs. Old FE models
davidgreenberg
| Posted in General Questions on
We’re in the market for an M-series heat pump and dealers have been quoting us the older FE models rather than the newer FH models. Is it a mistake to purchase an older model that will probably be discontinued sooner rather than later? I would think so. Thoughts? Thanks.
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Good question for any appliance. Could the older model had more revisions for quality? Could the new model be better by the numbers, but not field proven yet? Its risky either way. Since it's a draw go for the newer model and hope for the best. Just make sure the installer warranties the install and the product. Had some problems on both accounts. If the installer will warrantee the mini split in writing you should be good...
From the Mitsubishi web site, it looks like the new model has significantly better efficiency. I would ask for a quote on the new models. It would be hard to impossible to predict which would be more efficient but the efficiency improvement looks pretty clear. Unfortunately it would be rather complicated to figure out exactly how much energy savings that would mean in your particular application.
Efficiency rather than support is the reason to go for the FH series if you can. The FE series has a very good track record and is pretty efficient even at low temps, but in most cool climates you'll get ~10-15% more out of the FH, and in temperate climates with seasonal average temps north of 40F, as much as 20% more, if the test submittal sheets are to be believed (which they mostly are.)
For instance, the FH12 delivers 12.5 BTU/ watt-hour @ 47F at a the fully speed modulated output of 13,600 BTU/hr:
http://usa.mylinkdrive.com/uploads/documents/4561/document/MSZ-FH12NA_MUZ-FH12NA_Submittal.pdf
The FE12 delivers 10.6 BTU per watt-hour @47F at 13,600 BTU/hr
http://www.younits.com/media/wysiwyg/Literature_PDF/Mitsubishi/MSZ-FE12NA-8-MUZ-FE12NA1_Submittal.pdf
12.5 BTU for every 10.6 BTU is an 18% improvement in efficiency.
That's the equivalent of going from an AFUE of 80% to an AFUE of 94%, in fossil-burner terms.
At the +17F mid-speed modulated level testing the FE comes in at (7900 / 750W =) 10.5 BTU/watt-hour,...
...whereas the FH comes in at (8100 / 720W= ) 11.25 BTU / watt-hour....
...which is only about 7% more (not 18% more) but it's still more.
Bottom line, climate matters, but also sizing it correctly. Sizing it such that it spends most of it's time modulating at part load without a lot cycling on/off makes a real difference in the as-operated efficiency.