Mini split sizing
We are looking to add a mini split to replace electric baseboard heating . Located in Langley BC.
January February mean daytime temperature is 36 F, night time 33F, night time temperatures go below freezing maybe 15-20 times all winter and only to the high 20’s F.
We live in a 2nd floor in law suite around 750 – 800 square feet , open concept kitchen family room, an additional bedroom is not heated as it stays between 58-65F.
Presently heated with2-500watt and 1- 1250 watt electric baseboard heaters (3413×2.25=7679btu).
Night time setback to 62F, daytime 69F, however it generally takes2-3 hours to bring it back up in the morning. Only a few times a winter does it get somewhat cold into the low to mid 20’s, then a plug in electric heater is used to bring the temperature back up quicker in the morning.
So I am looking at Gree 9000 btu and a Gree 12000 btu .Specs for 9000btu: cooling cap;1535-12966,heating cap:2388-13648, seer:38 hspf;15.
12000 btu specs:cooling cap:3,100- 13,000, heating cap: 3,071- 18,766, seer: 30.5, hspf :14
当我查看HVAC互联网站点时，他们建议使用9000BTU，少于400平方英尺，12,000 BTU 5-600平方英尺。
Am I missing something here? I think either one would do as they both modulate quite low in heating (2388 &3071) .
Any thoughts would be appreciated!
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Replies
You need to figure out your heat loss before any decisions. See many other posts here on how to do it.
At your fairly temperate -5C heating design temp just about any 9000BTU mini-split would cover the entire load, as you correctly surmise from the maximum output numbers of your existing baseboards that are doing the job.
For reference, Vancouver Airport's 99% design temp is +25F/-4C :
https://higherlogicdownload.s3.amazonaws.com/ACCA/c6b38bda-2e04-4f93-bd51-7a80525ad936/UploadedImages/Outdoor-Design-Conditions-1.pdf
With a mini-split it's less efficient to use deep overnight setbacks. Using set backs it'll use a bit less than half what the baseboards use, but if you "set and forget", tweaking it up or down only a degree or two at a time it'll use just a third or less.
Thank you for the confirmation Dana, I have read many Q&A columns over the years and I have read many times yhe importance to size it correctly.
So the 9000 btu model would be the better choice over the 12000 btu model as the seer &hspf is higher?