Mini Split Performance in Subzero Temps
WB52
| Posted in General Questions on
Considering ductless mini splits on a pretty good house build. Zone 7 (Northern MN). Looking for some feedback and performance reviews. What have been your experiences? Thanks!
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Here's a post from northern MN.
https://www.greenbuildingadvisor.com/article/a-follow-up-from-northern-minnesota
I'd be also interested in what other's thoughts are.
Thanks.
I just had a clients multizone Mitsubishi shut down completely at -20 in VT for a few hours. Its a small 700sf well insulated and tight (.56ACH) new construction so the temps didn't really drop drastically from where the occupant liked to keep it ( 64 normal daytime down to 55 after an unknown number of hours with no heat). By the time the sun came out and temperatures were back into the negative teen temperature range, the system fired back up and kept on keeping on.
Good info, I lived in MN on several occasions but not zone 7. The heavily insulated zone 7 house in the blog (post/link above): "predicted annual consumption (as opposed to load) of 12.6 MMBtu/yr for heat, and 1.3 MMBtu/yr for cooling, for a total of 13.9 MMBtu/yr predicted consumption". Does not make much sense to talk about cooling in zone 7. For heating, 12.6 MMBtu/yr heating is impressive for 1,575 sq ft, some wood stove and other ASHP/electric resistance. In three years of operation, I've experienced lows of -15F and the Mitsubishi ASHP still performs sufficient for 65+F (2100+sq ft zone 5 with total annual ASHP consumption heating/cooling of around 22 MMBtu/yr; noting some additional ng BTUs with a direct vent fireplace mainly used for ambiance and potential backup if ever needed).
We're in zone 6 Maine. It's only gotten to a few degrees below zero so far, but the mini splits are keeping us warm.
At my Vermont home the lowest temperature we have had this winter was minus 17 and my Fujitsu kept me warm without shutting off.
We are in the Colorado mountains above Denver. Our ranch home has a single nominal 48K Mitsubishi Hyperheat unit that so far kept the house at 70F during a night that went down to -17F. It was running full blast, but did the job. The unit is probably oversize for normal cold weather temperatures, but was much appreciated that night. The output of the minisplit system is de-rated substantially for the altitude - 8100 ft.