Best Value Mini-Split for Cooling, Some Heating?
Climate Zone 6A, Toronto Ontario
I was at my Mom’s place over the weekend and we were discussing windows and air conditioners for her small house. Her house is a small 1970’s backsplit layout, about 1500 sqft including the rear basement living area, all 2×4 construction. Right now all she has is a window mounted air conditioner that she places in the master bedroom which is on the upper level a the rear of the house. It does a poor job of cooling the house but does give her relief at night for sleeping.
Her bedroom window needs replacing (rotten wood frame) and I would like to see her get an efficient casement style window to help keep her room warm in the winter. The original 1970’s window is a slider. If she replaces it with a casement she may not be able to use a window mounted air conditioner.
I suggested to her that a mini-split heat pump would do a decent job cooling the main part of the house, and that another one could be used in her master bedroom. She could also use them for a bit of heat in the spring/fall if necessary before it’s cold enough to need the gas furnace running, but these would mainly be used for cooling.
What would you recommend as very “high value” mini-splits that would be used mainly for cooling and/or dehumidifying? I think top of the line modulating models would be way overkill for her application, but perhaps there are multi-stage or cheaper modulating units available?
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Replies
Why not use it all year round? I'm in the same climate zone and the Fujitsu ductless mini splits (one per floor in a 2400 sqft home) have no issue with heating all winter long.
Hi Calum,
If I had started researching these things a few years ago I could have saved her the hassle and expense of dealing with her gas furnace install. The guy who installed it stretched it into a six month job and still didn't get it done very well. If I knew then what I know now I would have definitely steered her in a different direction! Unfortunately I live about four hours away so I couldn't even really help out.
Now that the gas furnace is installed, it's surely cheaper for her to heat with it when it's really cold out rather than use a mini split. However, it would be interesting to do some math and figure out where the balance point is (where the COP of the heat pump drops to the point where gas is cheaper). I'm sure I would recommend she use it for heating while temps are above freezing outside.
At max output almost any mini-split is going to be oversized for the cooling load of a master bedroom, but if you run the load numbers and find a model that can modulate low enough it might still be "worth it". The 3/4 ton LG Art Cool LA090HYV1 might be a good fit, since it's capable of modulating down to about 1000 BTU/hr in both cooling and heating mode. That's probably half or more the cooling or heating load for the room, but I'm not aware of any mini-split that will go lower than that. (Their cheaper LS090HXV only modulates down to 3000 BTU/hr, which is probably more than the cooling or heating load of the room.) It will still deliver over 11,000 BTU/hr @ -15C (wet bulb) and nearly 8000 BTU/hr @ -25C (wet bulb).
The 1 ton version (LA120HYV1 ) also modulates down to ~1000 BTU/hr, but has a bit more capacity, which may be worth it for the main part of the house if the load calculations warrant a 1-ton.
See:
https://s3.amazonaws.com/s3.supplyhouse.com/product_files/LG-LA090HYV1-Engineering-Bulletin.pdf
There are fairly cheap cooling-only mini splits, but the minimum modulated output of most 3/4 ton cooling only mini-splits is over 3000 BTU/hr.
Thanks Dana. The smaller model shows a lot of promise, for sure.