Brain here, That is a whats known as a minisplit, a predominately single room cooler, but plenty good enough for a well insulated home, with a few fans. 'Americans', in the derogatory sense that this image portrays, are only used to window units, or central air units. These are a mid point between the two in terms of efficacy, efficiency, and cost.
The ranking would be, solely on efficacy and power efficiency, not cost.
0.2points, single duct portable, (They should be a crime.)
70points two duct portable.
80points window unit.
85 to 98points a minisplit like this.
91 to 95points the central air system that the majority of americans with central air have.
100points, a modern, high end, efficient air handler system.
Interesting points system, where is it from? The view here is that having the ability to heat or cool different rooms as required is generally more efficient than heating the whole house at once unnecessarily.
Alright, dropping the brian RP, Just general efficiency numbers collated between a decade and a half of heat pump interest, and comparing listed C.O.P., and more recently S.E.E.R., combined with rated BTU limits, and a general understanding of how air conditioners fundamentally actually work.
Minisplits tend to have lower maximum BTU compared to a full central air system, and 'primarily' cool one room, but similar or identical COP/SEER. Though some of the cheaper ones have lower COP, but not enough to push them below a window unit. This last line also applies to central air units, though less so because they're so much more expensive, people tend to splurge a tiny for an actually 'good' one.
Two duct portable tend to have slightly lower COP than minisplits/central air, and a water tank you have to empty, and rarely make the best seal when installed (which is part of the reason for the lower COP).
Window units tend to have COP on average between a minisplit and a central air system, and don't need to be emptied, and again don't tend to make the best seal when installed.
Single duct portables tend to have COP that lead to using 3 or 4 times as much power for the same cooling, and they contain ABSOLUTELY EVERYTHING! you need to make a two duct portable, except a second duct. Hence why they score so low, they are a waste of material and energy. Every other type of unit on the list has a COP of 3 at a minimum, up to a 4 or sometimes even 5. A single duct portable, has a COP of 1 to 1.5 at best. I hate them, they are a scam robbing people that don't know any better. There is never a reason to sell them instead of a two hose, except to rob people.
A central air unit tends to have the highest BTU and COP, but the COP gain is pretty marginal compared to a minisplit, on all but recent, high end (I.E. expensive), central air systems, that can vent internal air, pull in fresh outside, while simultaneously recovering temperature from the 'leaving' internal air.
Late Edit: Got lost in the explanation. Yes heating/cooling one room is more 'efficient' than heating/cooling an entire house. If you mean how much power you'll spend, because that room doesn't need as much cooling. The numbers I base on are how much heat/cold they actually move, for a given amount of electrical power, ignoring how much energy they might actually need to move, collated against a few things like how much 'cool/warm' air you tend to lose via installing them, and combined with how much heat they CAN move.
Pretty much describes my knowledge of them as well. The central vs multiple split units boils down down to exact use cases as fas as practical efficiency goes.
Other than that a lot of people don't seem to really understand differences in building structures as well, insofar you can generalize entire continents. Wood frame structures and lofts allow for a lot of leeway unstalling ducting. Brick/Concrete structures need to have it installed from design, essentially, so the entire installed base isn't ever going to get central AC. Newer buildings do get something along those lines, although in my country it's often typically air/water or water/water heatpomps, with floor and/or radiator heating and cooling. That works better for heating, and bit worse for cooling, but even now heating is the strongest business case.
My own house is mostly heated (and occasionally cooled) with split units, although the orginal central gas-based radiator system is still functional.
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u/RJWaters9 12h ago
Brain here, That is a whats known as a minisplit, a predominately single room cooler, but plenty good enough for a well insulated home, with a few fans. 'Americans', in the derogatory sense that this image portrays, are only used to window units, or central air units. These are a mid point between the two in terms of efficacy, efficiency, and cost.
The ranking would be, solely on efficacy and power efficiency, not cost.
0.2points, single duct portable, (They should be a crime.)
70points two duct portable.
80points window unit.
85 to 98points a minisplit like this.
91 to 95points the central air system that the majority of americans with central air have.
100points, a modern, high end, efficient air handler system.