Multizone Compressor vs. Two Single-Unit Compressors
jgold723
| Posted in General Questions on
We’re getting estimates for mini-split heat pumps for our 1970’s split level in southern Maine. We have two proposals, each for two heads, 1 on each level. One contractor is proposing a multizone compressor, the second two single-unit compressors.
Is there an advantage to one method over the other?
Both are selling Mitsubishi products
FWIW, the two-compressor cost is lower than the multizone.
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Replies
One-to-one matched systems are generally more efficient than multi-head systems, because the one-to-one compressors generally have significantly better turndown ratios. The independent systems would also provide better zone control than two heads on a single compressor. With a single compressor, there is generally some refrigerant routed through the second head, even when it is not calling for heat/cold. If the one-to-one separate systems are cheaper to install, I would definitely go with that option. As always, make sure the systems are properly sized for your loads. Have a Manual J heat load analysis performed, preferably by an independent contractor. With minisplits, there is definitely a "Goldilocks" zone where proper sizing gives best energy performance and comfort.
1:1 systems generally have a better turndown ratio, which means they avoid short cycling. Some of them are 4.5:1 or more.
2 1:1 systems also gets you redundancy in case of failure.
Plus, it's cheaper. It's a win all around.
1:1 for sure. If it is cheaper that is a bonus.