Multizone Mini Split?

[drps10]

I bought and installed myself Mitsubishi hyper heat 42k btu unit with 4 indoor units. If I were to do it again, I would do 2, outdoor units. Better energy usage for my layout vs one big unit. We never had central air (I was tired of window units) and the heat is supper efficient! I went with Mitsubishi because they make the smallest indoor units (6k). I have a smaller house and the bedrooms are really small. Thr 6k are still a bit to big but manageable.

This will be the he second winter coming up but last winter was mild! The efficiency of the a/c was amazing. Even when it was hot out (110* heat index) it was only pulling 9 amps. I’ve seen it higher but that’s when I waited till it was 80* in the house and turned them on to 72*.

We have baseboard electric heaters which I really like, but the mini split are just as nice because you can set the temps in each location too. I felt like it was the warmest the house has ever felt because it was an even heat trough out since it seems to always be running very low. Not the cheapest to buy, but I wanted the name, the -13* heating and small indoor units.

 

[740GLE]

I'm skeptical. Pointed internally to measure the air stream or externally to measure across the room?

Externally pointed at the room, it rotates constantly while the unit is on.

 

[400bird]

Externally pointed at the room, it rotates constantly while the unit is on.

That's pretty cool idea. Does it rotate separate from the vent

 

[740GLE]

Yup rotates left to right, it’s on the bottom of the unit. It rotates constantly even though I keep the vents fixed.

 

[NEHP]

Look at SEER values of single head units vs multi heads, it appears single head units will win hands down vs multi head.

Down side of running 4 separate units is wiring/disconnects then also potential for 4 different refrigerant leaks.

Personally we went with a 3 head unit (only using 2 heads), 30k BTU Mitsu hyper heat, for ease of install, all on one side of the house.

So far so good but we’ve only had it for a couple weeks and weathers been seasonably cool.

You still have potential for 4 different refrigerant leaks with a multi head. Your single units out perform multi head units and with most brands the single units have more features than the multi heads. With a multi head unit, if you have a problem nothing works, with single units the rest of them will still work. The only benefit to a multi-head unit is you only have one box outside!

 

[timselectric]

Another issue with a multi head. Is they are all heating or cooling, at the same time. You can't raise the temperature in one area and lower the temperature in another.

 

[ImAnIdiotPleaseBePatient]

I ended up installing 4 single zone systems because multi head systems don't come in the 38 seer ?

I am so confused about seer ratings. How can a 9000btu AC that runs at 1400 watts be that much more efficient, than... let's say... a 13seer 12,000btu window AC that runs at 1500 watts. The whole seer rating thing makes no sense to me. Is a 30 seer supposed to be half the watt/btu as a 30 seer unit?

 

[hwy17]

It's all about the turndown, the 9000 btu mini split can go down to like 3000 btu at 300 watts or whatever, and SEER simulation includes a lot of light load periods.

EER is a much dryer figure that you will probably find more value in if you dislike the SEER magic math.

I think SEER is broken when units can game the calculation to get to 30 or 40 which is ridiculous.

 

[ImAnIdiotPleaseBePatient]

It's all about the turndown, the 9000 btu mini split can go down to like 3000 btu at 300 watts or whatever, and SEER simulation includes a lot of light load periods.

EER is a much dryer figure that you will probably find more value in if you dislike the SEER magic math.

I think SEER is broken when units can game the calculation to get to 30 or 40 which is ridiculous.

Will check out EER. I remain very skeptical that running at 1/3 or 1/6 load with a similar watt/btu is going to result in some kind of massive 50-70% decrease in total power output. I might be wrong, but it doesn't make sense in my head whatsoever.

 

[hwy17]

They're supposed to get much better watt per btu at low turndown. My numbers were just made up. Mine doesn't get very good turn down cause it's a multizone lol.

 

[timselectric]

I wasn't concerned about SEER before. And I'm not concerned about EER now.
They are all super efficient, compared to the other options. No matter what rating says.
My decisions were made by features. And zoned comfort.

 

[tomy2]

I wasn't concerned about SEER before. And I'm not concerned about EER now.
They are all super efficient, compared to the other options. No matter what rating says.
My decisions were made by features. And zoned comfort.

I agree, sitting at the computer desk with a new mini-split close by, the thermometer says 74 and it's 42 outside. Even though my batteries depleted at 4am, not really upset about using the grid. These things use less electricity than the central heater did and no $200/month gas bill.