In op.z92p4mxowdg98l@glass "Commander Kinsey" writes:

Just had a reply elsewhere that said the USA 13 minimum SEER only applie=
s to split units, and that most single units are much lower. Any reason=
why split units would be more efficient?

A bunch of reasons:

1: "mini split" units tend to be inverter controlled,
with variable output cooling/heating. There's more
efficiency with a five degree temperature drop [a]
than a 20 degree one.

2: the mini splits aren't wasting energy pumping all
that air around through ducts. Also, less leakage
in places where, well, the conditioned air is leaking..

[a] standard units have the compressor (cooling part)
fully on or off. The thermostat will kick it on
and, well, off as needed.

Hence if you only (for simplified example) need 5,000
BTUs/hr to keep your place cooled down (let's say it's
only a tad warm outisde) and your system is rated with
a 24,000 BTU (two ton) output, it'll cycle on for one
minute, then off for four, on for 1, off for 4. Rinse,
cycle, repeat.

A variable output unit will drop its output to 6,000 BTU,
so stay "on" for 4.5 minutes out of five.

The air temperature drop (the "delta") will only be
a few degrees instead of the 25 F typical of a full
power operation.

NOTE: there are now a _few_ window units that are
finally available in a variable output model.

So far _only_ for cooling, none yet with heating.

I picked one up earlier this year. It is, indeed,
much quieter, no "ker-thunk" when coming on, and
a gentler air flow. More efficient, too.

They're available from LG (formerly Lucky Goldstar).
In the US the _only_ general purpose retailet that
handles them is Home Depot. Others might, soon.

There's a _minor_ feature/annoyance/get used to it... change.

With a standard, say, 10,000 BTU unit, if you left it
off then came back to a 90 degree F room, then turned
it on, you'd get a nice blast of cool air in your face
30 seconds later.

With the LG's, since they're inverter units which measure
how much cooling is needed, they start off with just
a bit of chilling... so you don't get that refreshing
and icy flow.




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