re: pricing. I got several quotes. All fell in the same ballpark. It took some haggling to get it to that price. I did my research, including finding this site (
Adding a Programmable Thermostat to Mitsubishi Mr. Slim Heat Pumps | Clean Energy Wonk) where, ignoring his rebate, he paid a lot more. And that leads to the next part... My number also includes three of the wireless programmable thermostats (which run
~$300 each). So for primary rooms (living room/kitchen/master bed) I can set normal 5 (mon-fri) and 2 (sat-sun) programs. The other three indoor units I just use the remotes on demand. The programmable is.... ok. I've used better, but, after a lot of playing and reading of the manual, I switched it out of default mode (designed for businesses, not homes) and it was better.
Energy Bill Example
Dec 2012 (Natural Gas Boiler Heat):
Gas Usage: 120 Therms
Gas Price: $125.24
Elec Usage: 619kWh
Elec Price: $82.30
Avg Temp: 44
Total Price: $207.54
Dec 2013 (Mini-split heat):
Gas Usage: 21 Therms
Gas Price: $32.77
Elec Usage: 1938kWh
Elec Price: $269.42
Avg Temp: 40 (yea, colder)
Total Price: $302.19
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Yes, they're are WAY quieter than a window/wall unit, luckily, but, they still wake me in the middle of the night as the compressor kicks on and the freon flows. Winter months are the worst as it's a loud 'tick', rather than just the normal drone of a window unit.
I can also hear one of the outside units kick on when the compressor kicks on and the fan spins up. That unit IS under a set of windows though.
Your mistake for locating outdoor unit at the head of your bed.
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Two separate paragraphs. Reread. No one said the outside unit was anywhere near a bedroom. The INSIDE unit is what wakes me.
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Originally Posted by jeff5may
Total mismatch = 14000 BTU
My big question here is: why didn't you just put all the same indoor units in?
2 x 9k on a 20k odu = 2k mismatch
4 x 9k on a 36k odu = 0k mismatch
Running many zones takes a balancing act to run efficiently. For example, the zones that gobble up heat and cooling should share one unit. The other unit should hardly ever run. Kind of like a primary and a backup heat source. No idea on which zones use what load, but it doesn't take much science to figure out. If you have your system(s) rigged that way, it will save you money. Even with a 1 ton mismatch.
Hmmmmm....
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You're talking about over-sizing rooms. the 6ks are in small rooms (~10x10). The 9ks are in larger rooms. Even 6k is overkill, but there's nothing smaller. And the outdoor units don't really come in ANY configuration. When talking multihead from Mitsu the options are 20kbtu (runs 2 inside), 24k (runs 3 inside), 30k (runs 3 inside), 36k (runs 4 inside) and 48k (runs 8 inside, plus another junction box inside).
My configuration would have been either 54k total or 56k total. (Yes, that's a lot of power. I believe a typical ducted system would have been 2.5-3T.)
I do however believe one of my rooms should have been a 12k, but, too late for that now.
The point of these systems is to heat and cool rooms as needed. Not the entire house. THAT's why they're efficient really. Not a bad deal for summer. But in winter, every room, especially ones with any piping, need to maintain a certain temp.
The point of how installation was done was partly ease and to keep from running 90 degree joints on the copper. One outdoor unit on each side of the house. 2 sets of hoses/wires run up one side, 4 sets of hoses/wires run up the other.
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-The radiator will 'ping' when it expands and contracts, mostly only during extreme temp swings. Sounds like the noise a submarine ping makes in movies. It may be less annoying to some, or simply they get use to it. I don't hear it too often and it was most often during very cold winter conditions.
-The plastic will also expand and contract and shift. Because it's made of many plastic pieces they 'tick' and sometimes 'crack' during this movement. This I find most annoying as it has a cheapness factor. Those with metal baseboard heating, or nearly all window A/C units or those hotel like all in one models never hear this because they are made of metal.
-The refrigerant will 'whoosh' quite noticeably too. You might remember this noise from an older fridge. The flowing noise is more noticeable when the unit ramps up or goes into defrost. I notice my unit tends to ramp up and down most during summer cooling, runs steady during winter heating, except during defrost which is a more extreme ramp up of cooling mode, and the fan is near silent then too. As it's just a plastic shell, it doesn't hide the whoosh noise at all.
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This.
Also, can't use NEST with these.
I'm not trying to start a fight over these things. And I realize the OP made their decision and I hope it's worked out for them. Personally, I see mini-splits as an experiment. That's how I looked at it going in anyway. My problem is my experience. My experiment turned out with poor results. It was 6 months of constant work to get them working at all. (They leaked refrigerant for 4 months) Or to not drain condensation inside my house.
There aren't a lot of people that try to handle an entire house with just mini-splits. I turned on the A/C portion yesterday for the first time this year. They cooled the room. Yay?
I'm in MD btw. House is a Cape Code at roughly 1200sqft.
BTW: I'm the oldest Intro on the Introductions page, wow....
http://ecorenovator.org/forum/introd...timore-md.html