Mini-split HVAC - Cassette vs Wall

[kronic24601]

Hi There,

CONTEXT

I am remodeling my garage (so for DIY) to build a part man-cave part workshop. I will be insulating and drywalling everything, but I was planning on having someone else install the HVAC unless it seems straight forward (I don't have vacuum equipment etc.)

- I live in Los Angeles where temperatures swing from low 40°'s - 110°f
- My garage is about 450 square feet

Originally I planned to install a cassette system

I have had two HVAC installers come out and give me estimates.

MAIN ISSUE

One of the installers insisted that no one uses Cassette style systems in so cal since they "don't work as well".

He said they "don't get as good of airflow as the wall mount variety" and If I installed the unit it would not be "able to cool down the space".

I was considering these two units: (both 1800 BTU units)

• Cassette - Cooper and Hunter - ch-18msphct-230vi
• Wall Mount - Cooper and Hunter ch-18msphwm-230vi

Documentation on them implies that the airflow is marginally greater with the cassette units. All google searches have led me with no indication that there is anything wrong or inefficient with the units, nor can I find anything talking about its "lack of effective airflow". That said, I have never seen a Cassette style system in Los Angeles and they are a little more costly.

QUESTION
Does anyone know if this is bogus? Accurate? Why?
Any other feedback or consideration I should make in this factor aside from price and aesthetics?

Thanks in advance!

 

[Black Oak]

Cassette style is generally regarded as a maintenance problem , and if not installed right , a condensate removal problem . I wouldn't even consider one . Just my 2 cents .

 

[LS6 Tommy]

I wouldn't sell a cassette to an enemy. Lousy airflow/distribution, drips/leaks, service nightmare.

Tommy

 

[yeldogt]

The Cassettes were originally used commercially -- they are all over the place.

I have two at my beach house -- each one doing a large bedroom on the second floor ... big cape style house. Both are Mitsubishi and both installed by a large HVAC contractor doing many. I guess installed about 4+ years ago. They were able to use a gravity drain for each.

Let me say this as a very general statement. HVAC people install what they install -- ask for anything out of the box and you get a deer in the headlight sort of look. They don't want to take chances with something new and different (to them). It's the same when you ask about VS in typical split equipment --- or if you ask many about zoning to better control temps or to only install one system in a house. Most want to install what they know and move on. Since the cassettes were more commercial to start out -- you have residential HVAC people now just starting to doing the wall units .... many have never installed any of the other types.

It was not too many years ago when you asked about Mini splits -- most did not want to install. Now it's changing as they are being so widely used ... and money to be made. But, the resistance is still there.

When I did my first mini back around 05 -- LG was a big player. I still own the house where it's installed .. and still working. Over the years I have heard little good about LG. Since that first install I did a Fujitsu in 2013 as well as a Mitsubishi. The last 5 years have all been Mitsubishi.

Now I do like the Mitsubishi the best ..yes. But, I firmly believe many of the problems people have start with bad installs. I have seen some really bad installs. None of mine have ever needed anything -- I clean the filters.

So -- with all that out of the way. The reason I went with the Cassettes for my cape was because there was no wall room for the heads. The way a cape is built with wacky ceiling angles and dormer windows -- the wall heads would not work. Had I the ability to do the heads -- I would have. Why -- the Mitsubishi heads have many options and the best head that I use has an eye that actually knows when and where the people are. The lines went into the attic and down the side of the house. Drains -- separate.

My two cassettes are connected to a three head Mitsubishi system -- each of the heads are 12k and the compressor is 30k. What I have found in real use -- the cassettes with the four outlet points and what seems to be stronger fan ... can really cover some area. Since we tend to just maintain the the second floor at that house for overflow. The cassettes quickly cool or heat the space -- one of the bedrooms is 26x 20. We keep them in the 78 range in the summer when unoccupied. The cassettes work off a wall thermostats -- only have three speed fan ... so they work a bit differently vs the heads. I can see how a large cassette in the center of a garage would be nice -- the filters are easy to clean.

The cassettes do install differently -- mine hang from threaded rods. Some need an access square in case something does goes wrong with the control unit inside and it can't be addressed from above some how. In a garage making provisions for the Cassette possible service would be easy.

For both the Wall and the Cassettes units -- if you can't get a gravity drain to work .. they makes small pumps. It does seem that these are a source of problems and if they stop -- the units can leak. I have never had to use a pump so I can't add anything.

I also can't add anything about the a given brand --- other then I do believe they have gotten better all around.

 

[jjrbus]

I find maintenance on the wall units a PIA, they are not designed for cleaning or service and I have had a mold issue in one that had to be disassembled to clean. There are 100's of sites on the net pertaining to cleaning wall units.

Out of curiosity I looked for cleaning a cassette unit, nothing, nada, zip, no thanks. Not an issue if you hire everything done, I am a poor old senior on a fixed income who needs to be self sufficient.