迷你拆分与中央空气在较小的新房屋中具有开放概念
大家好！
We are getting close to having our new home here in Wisconsin fully framed and approaching the electric and HVAC install phase. After researching mini-split systems and their efficiencies, I’m really liking them and wondering if a 2-zone, 21.5 SEER system might be a good option over a traditional central air system with ductwork??
Here’s the lowdown below.如果您在GBA上的任何一个聪明的人都可以提供有关哪种方式的洞察力或建议，那将是如此感谢！I’ve spoken with some HVAC contractors and it seems that mini-splits are a little uncommon and most aren’t well versed….
The Lowdown:
We’ll have a finished basement that has radiant in-slab heat for the winter months. Basements typically stay quite cool here in the summer, so I’m okay with not having A/C pumped into the basement; and I plan to install a permanent dehumidifier to control any humidity.
Moving upstairs (SEE ATTACHED LAYOUT) we would install, say, an 18k BTU wall mounted ductless air handler in our large, 18×31 (560 sq. ft.) open concept livingroom/kitchen. Then, in our master suite we would place a 12k BTU wall mounted ductless air handler to keep that side cool. These would be connected to a 30k-36k BTU Condenser that would be mounted just outside on the same wall. One possible criticism is that the wall mounted air handlers will only be ~8ft. apart, however they will be separated by a wall/door.
If this setup successfully keeps our upstairs cool in the summer, then come winter the mini-split system will also provide heat, and we would also be adding a gas fireplace with a blower in the big room to assist with heating, and for aesthetics.
我觉得，通过这种设置，我们将达到最大效率，并且通过我所拥有的数字，这不仅要安装，而且每个月都会降低成本！还要注意，我们将在墙壁上有R-19绝缘材料，天花板上的R-25+。
这是系统的链接（酷先生）：
https://iwae.com/shop/30k-btu-21-5-seer-mrcool-diy-2-zone-ductless-heat-pump-split-system-12k-18k-ha21028.html
对不起，您需要长期的建议，并提前感谢您的任何建议！！！
尊敬，
卢卡斯
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Replies
If you have a basement, I would recommend a ducted mini split in the basement. Given your layout, the duct runs could be very simple. If you go with two ductless heads, I would look at Mitsubishi’s 9k hyper heat units. They turn down to 1,800 btu/ hr and with one in each room should be enough. Although I would consider putting in much more than R25 in your attic depending on the specifics.
最好的方法是让第三方（不是HVAC安装程序）完成手册J。
辐射是否已安装？如果没有，即使安装了管道，也要为两层捆绑捆绑捆绑包并获得两层式的小型插图。
I would run your place through one of the online load calculators (coolcalc or loadcalc). Chances are very very slim that a 900sqft of space needs a 2.5 to 3 ton heat pump for heat.
As others have said, for a new build, go for a slim ducted unit. Better efficiency, better air distribution and comfort and less maintenance down the road.
Paul is correct about the basement floor heat. Any reasonably insulated basement has a heat load bellow 3000BTU, even with floor heat, the floor will never feel warm. A couple of registers off the ducted unit is all you really need, if you want more comfort bring the registers down to floor level to blow along the slab.
P.S. Wisconsin can get pretty chilly in the winter, R19 feels a bit on the low side, at least upgrade to HD batts. Even inch or two exterior rigid insulation would also not be overkill (most siding can be nailed up directly through 1.5" of foam).
Thank you so much for your recommendations!