Can someone tell me a few minisplit models that work exceptionally well in the colder climates?
Climate zone 6.
Approximately 1000 square foot area. Will be very well insulated. R40 floor, R60 or better roof, R30 walls with well detailed air sealing. Approx 76 sf of triple glazed windows.
The floor plan is very open, so I’m hoping one unit will be sufficient, with some electric baseboard supplemental heat in strategic areas.
This winter was horribly cold, with many days below zero, but I wouldn’t call that the norm. The coldest day was approx -18 below for the low, and approx -8 below for the high.
It seems like the air source split systems are improving so fast that the old models are nearly obsolete overnight. Anyone get to see a demo of any great new systems coming out?
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Replies
We're using the Mitsubishi Hyper Heat which are good to about -13oF. Good units!
Rick,
As Dana Dorsett has noted several times in response to similar questions, the Fujitsu AOU-9RLS2-H and the Mitsubishi MSZ-FH09NA both have a rated output at -13F or lower.
I have Comfort Aire Model A-VMH27TC, and I find them to be less than stellar. I live in climate zone 6, and have two heads installed in my 1800 foot garage/shop. The boiler was used most of this past winter, and certainly any time the temp got below zero. At 2 tons, the heat pump wasn't designed or intended to meet the entire heating load; however, at cold outdoor temps, the units struggled to blow anything above lukewarm, to at times even cool, air. Warmer than the outdoor temp, mind you, but certainly not pleasantly warm like it accomplishes now (35 degrees today, and boiler is off).
Mitsubishi M-series mini-splits:
http://news.mehvac.com/Bulletins/FH_Product_Guide.pdf
Fujitsu XLTH mini-splits:
http://smartgreenbuild.com/pdf/Fujitsu-RLS2H.pdf
Run a heat load calc on the place for your load at your 99% outside design temp, and choose accordingly. Be aggressive- on your load assumptions, don't over-size it. Sizing it for the average load is better for both comfort & efficiency than oversizing by more than 50%, and even when it's not keeping up it'll still be providing the lion's share of the heat at a COP of 1.8 or better even at -15F, and you can make up the difference with resistance heating or some other supplemental heating.
The somewhat older "MSZ-FExxNA" Mitsubishi Hyper Heating units will get you there too, but the M-series "FH" versions deliver ~15-20% more heat per kwh, and are worth the modest up-charge if you can get them. The M-series -FH minisplits were just released, but are clear follow on decendants of the -FE units, and targeted directly against the Fujitsu XLTH (which have somewhat lower HSPF efficiency numbers, and model-for-model comparable output.)