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Mini split ceiling cassettes

Posted by ratflinger (My Page) on
Fri, Oct 26, 12 at 22:20

Anyone had any experience with the cassettes? Seriously looking at mini splits (Mitsubishi is better represented in San Antonio) for new construction. We are fine with the wall units, but might consider the cassettes if performance is the same.

2nd ? - If I have a unit in the master BR that is sized to handle an area consisting of the MBR & Master bath will that be adequate or will I need a unit in the bath?


Follow-Up Postings:

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RE: Mini split ceiling cassettes

Check the manufacturer data, but I think that you will find that anything but the high wall units are less efficient.

Have you looked at the small air handlers for the MRr/bath combo? They take short ducts to condition more than one room. You would need a very large bath to install a separate unit. You could use a jump duct to move air from the bedroom to the bath.


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RE: Mini split ceiling cassettes

We have two ceiling cassettes and three wall units.

The ceiling cassettes are very efficient. We use one to cool our main open floorplan and one to cool the master bedroom. We have a separate wall unit in the master bath. I'm really glad we have it because our bath is on the south side of the house and had two sky lights so gets tremendous thermal gain. If you leave the doors open between your bath and bedroom then it may be OK if your bath doesn't get alot of thermal gain. Also if you can position the unit so it throws air into both rooms that will help.

You can look at the specs. for the various units to check the efficiency, noise etc.

I couldn't find anyone to install the units with the ducting to different rooms. I think that is a good solution for smaller rooms and would have liked to do that. The ducted ones are less efficient because the ducts run though unconditioned attic space in most instances so they loose some of their cooling.

Be sure to position the one in the bedroom so it does not blow air onto your head while you sleep. We had to close off one of the ducts in our ceiling cassette because of this.


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RE: Mini split ceiling cassettes

Thanks - I'll probably just go with the standard setup. Wife doesn't mind the unit high on the wall & if we move it will be into an assisted living home so I won't care if there's a small financial hit because of 'perceptions'. (I perceive my energy bill being lower & that trumps ascetics).


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RE: Mini split ceiling cassettes

The only place I don't like the high wall unit is in our dining room, the smallest room. It is obtrusive in there.

I was surprised to find that the Mitsubishi 6000 and 9000 BTU have the same size case. It seems like they should be able to make the 6000 smaller. Other manufacturers may be smaller.

Pay attention to the controls from different manufacturers. I think that others may be more flexible than Mitsu. There is not a true set-back. I can set on and off times, but not a setback. I like to sleep cool and have the room warm when my feet hit the floor and that can not be done. There is no hard-wired thermostat that can be use with the residential Mitsu systems. Others may be able to do that, but at an added cost.


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RE: Mini split ceiling cassettes

---> mic111
Did you run into any issues installing the ceiling cassettes since they range from 33"-37" square and joists are 16"-24" on center and joists would have to be cut to make the opening?


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RE: Mini split ceiling cassettes

Yes, indeed we did. Our first contractor cut the joists and did not properly brace them. They started to sag and the drywall started to crack. I had the city inspector out and fired the contractor. I hired a civil engineer to inspect and brace and provide letter that all was good.

The bracing was actually pretty simple. I forget the terms and such now but there are some clips they used and cross braced the cut joists to the ones next to them. I have an uncle who does construction so he told me what was the right thing to have done.

I also had the city inspector give me his opinion and there was a second type of bracing he thought would be OK. Also simple. It was to run a second beam parallel to the cut one and attach the two together.

We only needed a couple of extra inches. Also you can't cut anything if you have an engineered truss system. Ours wasn't so was OK to cut. So far no problems with what they did cut.

Then second contractor installed the units. However they didn't do the drainage properly so one of the drain lines froze and broke, putting water this year into our ceiling and swelling a beam over our door. Luckily we caught it very quickly so we have a small amount of water damage to the drywall. The door beam seems to have dried out. The water drain system in that attic is now good.

The other attic I'm keeping an eye on. I'm not sure it was done properly and have had no response from the contractor for what was used.

We used the Fujitsu compact ceiling cassette which is smaller than most. I had hoped we wouldn't have to cut any joists but unfortunately we did. In hindsight since we had to cut anyways maybe I should have picked a larger product for our main area. It keeps in down to 74 when it is 100 or more out but no lower than 74. It is 18K BTU. On days that are less hot it could probably go lower but I start to get too cold so haven't ever set it lower than 70.

We have the 12K BTU in our bedroom and that is a bit of overkill so probably could have gone with the 9K BTU there.

As far as I can tell for our area contractors don't know how to install these systems or are simply incapable of following the instructions in the installation manual. Other than that they are great systems. I can turn everything off at night except the bedroom. I could actually only run the one for the room I'm in if I wanted to but I tend to cool most of the house off during the day and then turn it off at night.

For the ceiling cassette in the bedroom we placed it at the foot of our bed. However even then the air from it is too strong so we had to close off the vent that goes over the bed. It is now a 3 way ceiling cassette and still does an almost overkill job cooling the bedroom.

Here is a link that might be useful: Fujitsu compact cassette


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RE: Mini split ceiling cassettes

It is unfortunate that contractors will not...or can not read directions. The cassette has specific instructions for suspending the units. Drain specs are very clear as well. I prefer the high wall units just for accessibility of cleaning the air filters. Some say they are ugly. My feeling is that once you see how well they work, the longer you live with them, the better looking they become. The top manuf of mshp units offer regular and free training for contractors. Ask which manuf's the contractors have attended training on.


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RE: Mini split ceiling cassettes

It is unfortunate that contractors will not...or can not read directions. The cassette has specific instructions for suspending the units. Drain specs are very clear as well. I prefer the high wall units just for accessibility of cleaning the air filters. Some say they are ugly. My feeling is that once you see how well they work, the longer you live with them, the better looking they become. The top manuf of mshp units offer regular and free training for contractors. Ask which manuf's the contractors have attended training on.


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