Minisplit efficiency – multiple single zone vs single multi-zone
I am strongly leaning toward installation of a ductless minisplit system to replace an archaic air handler used for heating and cooling. I’ve done a lot of research on mini-splits and would definitely prefer one of the ~-15* low-temp heating options offered by Fujitsu or Mitsubishi (this just makes sense as I’m in Chicago burbs). Currently from what I can tell these models are only available in single zone models. However, for our home I’m certain the sqf and layout of our home would mandate more than one interior unit. (2700 sqf ranch with bedrooms that are pretty well shut off from the living space).
I have several questions related to these products:
1) Are there any known/concrete plans to offer low-temp heating/ high SEER units within the multi-zone product set? In other words, would it be wise to wait another year or two to make this investment?
2) If there are no short-term plans by these providers to make these units available in the multi-zone platform, is there any objective way to evaluate whether it makes sense to go with a lower efficiency multi-zone vs multiple single zone units (meaning I would have up to three outdoor units)?
3) Separate but related question. We have a detached garage that gets good sunlight during the day. I’m curious whether it would be advantageous to install the exterior units so that they draw air from the garage (while still exhausting outdoors)? I’ve not actually tested this theory but I suspect the temperature inside the garage is always a few degrees higher than outside (because of solar gain & whatever heat comes up from the ground). The flip side is this would add ~20 feet of tubing to each run.
We live in Chicago so these units would be used extensively for heating. Even with a low-temp heating unit I know we will need supplemental heat. I do have a plan for this.
Lastly, I have an HVAC contractor with minisplit experience coming next week to bid this. My goal is to be as educated as possible prior to that meeting.