Mini-split ductless question..

[psmithrt]

This is just a general knowledge quote from an hvac dude to a question from a gent contemplating a switch from propane to a gshp. He knows his s%&#. Just thought since it pertains to this threads subject matter, it would make a good read:::




there is a core level difference between these two options..

with propane, say kept at the same exact price as electric heat per
BTU you still pay drastically less for heat with a heat pump... key
word 'pump'. with a heat pump you are *not using the electricity to
heat a resistance heater to produce heat directly. You are using
the electricity to *pump heat from outside to inside... by running the
heat pump compressor. That is vastly more efficient than burning
propane, or using electricity in an electric heater.... 'burning
electricity' so to speak.

Even if its say 40F outside, you can pump the heat out of that air...
via the refrigeration / compressor circuit in a heat pump..


When it gets much below 35 or 40F outside a heat pump begins to loose
its advantage, so are not seen as comonly in very cold climates.
These do come with electric resistance booster heat though for times
when it gets colder than the ideal range for heat pumps.. allowing you
to reap the advantages of a heat pump while, having the capabilty to
heat on the rare occasions its below 35 or 40 outside... it i not
nearly as efficient in the pure electric heat mode though. no big
deal if its only say 10% of its run time.


My guess you will save between 30 and 50% on heating costs by going to
a heat pump ...

**

If you want to really save money, go to a zoned system, Many ways to
do that. say one smaller heat pump for the bedrooms, used at
night... and one for the living areas, used in the day. then program
them to set back in hours those rooms are not in use... that will save
another 20 or 30%.

If you add an electric matress warmer you can run the bedroom system
much cooler at night saving a lot more money.


***

two systems have the advantage of redundancy... when one dies, you can
still live in the house.
....also two smaller units will tend to run nearer 100% of capacity
when each runs.. thats more efficient.

**
to save more undersize the systems by 20% or so.. this means for
instance that in the summer it may get up to 76f in your house between
3 and 6 pm (gasp)... but you will save on first cost, and run closer
to 100% of max load when you do run. (in humid climates there are
some caveats I wont get into here).


go with 14 seer units though...highest efficiency.. for many reasons,
operating costs and what that does to vastly extend the life of the
systems. Go with an ultra simple system (not carrier for
example)...Rheem is superb... Trane is not so bad. Complex systems
cost a lot more to repair.

**

to save a whole lot more, go with ductless systems.. these have a
component that mounts on the wall or like a radiator near the floor...
eliminates duct losses.. about 10%... and can zone to operate one room
at a time.. very very efficient... saving another 20% on top of the
two unit zoning I mentioned earlier. Not cheap to install though.
Daikin Kogyo and Mitsibushi both make them. The chinese are now
making them if you can find em, for about 70% less using the japanese
compressors (superbly reliable roller compressors)... search ebay.


The quality of the installation is crucial for whatever you get. ...
unless its window type heat pumps.. one in each major room. and dirt
cheap btw... offering 100% zoneabilty... when it dies just shove
another one in the opening. yourself... no service call. Most
major motels and many hotels have gone this route for those reasons.

***

geo thermal, using ground water for a heat source... very efficient.
costly to install and service.. easy to screw up the engineering,
local ground water issues vary..can be a big problem. for a large
building maybe the complexity is worth it... not for a smaller
home ..... imo. ymmv.


Phil scott.. in da business since 1810.

[psmithrt]

I just wrote you a long ass PM and somehow was logged out and it was lost. Please give me a day to regain my composer

[Xringer]

Hi guys, I've been too retired all summer to think about this project, but last month
I built the outdoor pad, started getting the 230VAC supply set up and just placed
my order for the Sanyo 2-ton I've been looking at. (Of course it's on back-order)!

I got some interesting (rumor?) news from the support guy I was talking to at
the dealer.
He said they got some feed-back from an owner who had been in direct
contact with Sanyo about the cold temperature operation of this model.
Sanyo says, They under-rated the unit. it will give full output (29,000 BTUh) all the way down to 17 degs!
And, down at (0), zero deg F, it will still give you 70% of full rating.
I think that's about 20,300 BTUh..

If this is true, I'll be golden this winter!!

I plan to post more as I dig into this project.

[Xringer]

East side of house, between house and garage (10' away).



I moved* the water tap down to the right about four feet, and will use the left-over hole
to feed out the 230VAC to the cut-off box. (provided with the kit).
*Used 1/2" SharkBite 90deg Elbows & PEX pipe.

The line-set will feed up (on the outside of the wall) to the 3 inch hole,
where it will connect into the indoor unit.

The main units look a bit like this.. This picture is not to scale..

[Xringer]

The Sanyo heat pump is working great.. Here's the URL to the install.
Sanyo 24KHS72 AC/HP DIY install project - EcoRenovator

[jackierae]

I just bought a Shinco 18,000 BTU Mini Split Unit about a month ago. You definitely want to go with the inverter technology. Much more efficient, and less noisy in my opinion.

[Xringer]

Originally Posted by jackierae

I just bought a Shinco 18,000 BTU Mini Split Unit about a month ago. You definitely want to go with the inverter technology. Much more efficient, and less noisy in my opinion.

Did you get the version that also heats?? (If you even need it down there)!
Here it is, in the middle of May, when it should be warm, and we are
still using the Heat mode of our Sanyo.. Not running up much of a bill,
but it's saving us a ton of money compared to oil heat..

[Kirch]

how well do you think a ductless split will cool an upstaris with 3 bedrooms and 2 baths? there is a small hall way 7'x15' and all the doors go off that. I think with the unit mounted on the wall in the hall it should be forced in the rooms fine. Only concern is with it wanting to go down stairs.

[Xringer]

It depends on how tight your house is, it's installation & etc.
My 24,000 BTUh Sanyo is cooling 1,200 sq ft down to 75 (it's 85 outdoors & very Humid).

The whole house is very comfortable and the Sanyo is just idling along at 420 to 440 watts.
From 5 feet away, It 'feels' like it's pumping out 4,000 to 8,000 BTU.. (A wild guess).

We might spend 70 or 80 cents on cooling today! (20 cents per kWh).

My system has a clear shot right down a hall to the master bedroom,
and it does the job..

Sanyo 24KHS72 AC/HP DIY install project - Page 7 - EcoRenovator


If you look at each of your rooms and can tell what size of window AC
would work in that room, and add them all up, (plus the hall)
you should get a good idea of how many BTUs you need.

Nice thing about inverter units, they don't use a lot of power,
if only a little cooling (or heating) is needed to maintain a temperature.
So, if you get one that's 12,000 BTU too large, it's not going to run
very hard and run up your Electricity bill..

The compressor and fan motor slows down and uses less power than
a 5,000 BTU window AC..
WikiAnswers - How many watts does it take to crank a 5000 btu air conditioner

I'm getting cold in here (down the hall in a small bedroom) and I see
the power meter says 420 watts right now..
From here, I can't hear it. I can hear the oil burner down in the basement,
but the Sanyo makes very little noise..
In the living room, the refrigerator is louder than the Sanyo!

It does make some fan noise when it's running hard in the morning
(heating) as it uses about 1500 watts for a while before dropping down
to 450-480 watts, to maintain the temp..

[Kirch]

Rich,
Thanks for the reply. Your install will be similar to mine. So your master bedroom is at the end of the hall and it cools it fine? what about the rooms along the hall........ how well do they get cooled? as mentioned, my only concern is a lot of the cold air dropping down the stairs. It is a fully enclosed stair case though. just an opening at the top.

forgot to mention I do have a Fijitsu 36kbtu down stairs and love it. Max temp. diff. for entire down stairs is less than 4 degrees.