Ceiling cassette location in a long, narrow room

[Steve W.]

I am in the process of taking bids to replace our aging (but still functioning well) furnace in the house. Due to an expansion by the previous owner, there are actually TWO furnaces. The second one heats the family room that was created when the garage was expanded forward, then a wall put across what used to be the middle of the garage. The wall between the laundry room and garage was removed, so the room is about 13x30. We plan on removing one more wall, making the room about 13x40.

When this conversion was done (probably in the mid-70s), they installed the smallest downdraft furnace they could find, 60,000 BTU. It's WAY overkill for the room, so it heats it in just a few minutes. That's great, but there is no insulation in the walls and only about 3" in the ceiling, so the room cools off just about as quickly. I am in the process of re-wiring and insulating the entire house, this room is next.

I am thinking this is a good candidate for a ceiling cassette mini-split. I have had a few companies here to bid on the job. Most assume a wall-mount unit when they hear "I want a mini-split", but have agreed that a ceiling cassette would work better, due to what's on the outside of the walls they want to use. I have been thinking of installing the cassette near the middle of the room, so it blows both ways, but one company rep insisted that it should be near one end. My thought is that doing that, you could only get air out of one side, and it probably would not blow the 35' or so that would be needed. Where should this cassette be mounted? Middle of the room or near the end?

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[Steve W.]

54 views so far, and nobody has an opinion?

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[Phuckin' Jim]

With natural convection, heat will move about the area.
I would install the cassette where it is most convenient.
Also consider a floor console if you don't want to put one on the wall or the ceiling.

 

[HamAndEggs]

I'd want it in the middle personally

 

[Steve W.]

Thank you both for your opinions.

I agree with the "middle of the room" location, could not get the installer to agree with me. His company is no longer in consideration for the job.

There is already too much "stuff" spread around the perimeter of the room to consider a floor console. The only possible place for one would be near the middle of one of the long walls. Since it essentially only blows up, it would only heat/cool the middle of the room, unless other fans are turned on to supplement circulation.

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[dave*99]

removed

 

[dave*99]

Is there attic above the room? There are mini splits that connect to ducts too.

 

[kaymccampbell]

I'd do middle-ish of the room, depending on exposure, I'd bias it towards the outside walls.

 

[nadogail]

My cassette is in the radio in the dash board.

 

[Steve W.]

Is there attic above the room? There are mini splits that connect to ducts too.

Yes, there is a bit of space, but the ducted models I have seen were a bit more expensive. And there is no existing ductwork, so that cost has to be added in, as well.

The last guy here quoted me a unit for just over 4k. Later, he called me to say they were not available at this time, the only other one he could find would be almost 6k. If I was willing and able to do it myself, I could have one delivered to my door for about $2200. I don't see why it would cost $4-6k to have one installed, so I might end up doing that.

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[beemerphile]

Pricing from every installer I checked was ridiculous. I bought equipment for a four head, two condenser Mitsubishi system for $7,800 including one ceiling cassette and three wall units. The quotes I got for turnkey were as high as $18,000. That is $6000 more than I paid for a high Seer Trane 4 ton unit including all new ducting and installation at my prior house. So, I did it myself.

I'd but the ceiling unit in the center as well. The diffusers on mine allow it to blow in four directions.

 

[Junkdrawer Dog]

With natural convection, heat will move about the area.
I would install the cassette where it is most convenient.
Also consider a floor console if you don't want to put one on the wall or the ceiling.

This^^^^ I've lived in a couple of places with ceiling cassettes. In fact, I'm living in one now. Both were installed an entry hallway, blowing into the main living area. With an open floor plan, convection and a couple of ceiling fans, heat moves around just fine.

 

[DaveMcLain]

In the 18x48 upstairs room of my barn I have two ceiling cassettes. They're mounted mostly in the middle of the room and having two of them allows the room to be "zoned" somewhat. When my wife is up there working on bookkeeping stuff she likes to run just the one that's far away from her so that it doesn't blow on her while she's working.

Running both of them allows for a quick cooldown of the room with the AC. From what I've seen the ceiling mounted units don't blow quite as hard as the wall mounted ones probably because the air is being blown in 4 different directions at the same time.

 

[dave*99]

FWIW—- wife and I were out to dinner last week. Sitting in a restaurant under a cassette. AC on. She wore her jacket all through dinner.
A high ceiling room would be better. How high is your ceiling?

 

[ArtisanFarms]

I would put it at least 6’ off of any end wall and relatively close to where people will be congregating in the room.

I installed two ceiling cassette units a few weeks ago. The installation wasn’t that difficult, but unless you have some sort of lift to position the cassette, it is definitely a two person job. It is also much easier to do before the ceiling is installed.

All of the cassettes I found weren’t true DIY style and required a vacuum pump for installation. Additionally, with my MR COOL units, the warranty isn’t available unless it is professionally installed.

 

[Steve W.]

Sorry I have not been back to check on this thread, have been recuperating from surgery.

A high ceiling room would be better. How high is your ceiling?

Unfortunately, the ceiling height is just a bit less then 8'.

I would put it at least 6’ off of any end wall and relatively close to where people will be congregating in the room.

The room is the family room/home theater area that will extend past the sliding door to the rear porch, then to the dining area and kitchen. The cassette will be pretty much near the door, in the middle of the room.

I installed two ceiling cassette units a few weeks ago. The installation wasn’t that difficult, but unless you have some sort of lift to position the cassette, it is definitely a two person job. It is also much easier to do before the ceiling is installed.

I don't remember the posted weight of the unit I'm considering, but I knew right away that there was no way I would be doing it alone. My son will be here to help.

All of the cassettes I found weren’t true DIY style and required a vacuum pump for installation. Additionally, with my MR COOL units, the warranty isn’t available unless it is professionally installed.

The one I am considering is not advertised as DIY, but the outside unit does come pre-charged. Renting a vacuum pump and gauges will not be a problem. I'll have to check the warranty situation, though, thanks for mentioning it.

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[Jackfre]

With a low ceiling i would be careful using a cassette. Dave 99‘s experience mimics mine. Also, they are a beast to clean and you want good access from above. They have a built in condensate pump designed to only pump up about 16” and then you have a natural drain. You will likely hear the pump cycle. As to position, look at how the room is to be furnished and used. Keep it a ways off from your primary seating position. Perhaps you could do a small bump out to accomodate a high wall unit. Long term I think you will be happier with it

 

[Steve W.]

I am not sure what you mean by “do a small bump out”.

What is getting bumped out, and where would I put it?

 

[justinjoyal]

With a low ceiling i would be careful using a cassette. Dave 99‘s experience mimics mine. Also, they are a beast to clean and you want good access from above. They have a built in condensate pump designed to only pump up about 16” and then you have a natural drain. You will likely hear the pump cycle. As to position, look at how the room is to be furnished and used. Keep it a ways off from your primary seating position. Perhaps you could do a small bump out to accomodate a high wall unit. Long term I think you will be happier with it

What he said. ^^

I am not a fan of cassettes. On top of the reasons above, most I've seen did not perform really well compared to wall units.

Why is a wall unit not an option ?

 

[chinboys]

I have 3 LG ceiling cassettes installed in the near-to-off-center locations of my bedrooms.
Two 12K and one 9K units to be exact.
Each room has a ceiling fan that predates the installation of these cassettes.

The cassettes' design has the center area pulling in the air to be conditioned and ejected by 4 perimeter adjustable\fixed direction vents.

Would I do it again? Perhaps or not. I find the wall-mounted cassettes to cool or heat faster and simpler to install.
Yes, I have 4 of this type too.

 

[Steve W.]

Why is a wall unit not an option ?

In my opinion (for whatever that's worth), simple physics.
- As mentioned in post #1, the room will be about 13 x 40, after one wall is removed.
- The only outside wall is one of the long sides.
- The ceiling is just under 8' high.
- The windows along the outside wall are too close to the ceiling to allow mounting a wall unit.
- The ONE area where the wall is long enough between windows is over the back patio.
- That ONE area is only about 10' from an end wall, meaning that air distribution to the other end of the room will be minimal.

My thinking might be a bit delusional, but I am under the impression that a cassette unit near the middle of the room will only have to blow a bit less than 20' to each end. If the air flow can be directed along the ceiling, it should make it just fine.

Although I have seen several wall units in places that I have visited, I have not been in these locations long enough to evaluate their finer points. This will be my first unit at home. I am also looking at putting two units out in my shop, but neither of them would be well-served by a wall unit, either.

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[justinjoyal]

In my opinion (for whatever that's worth), simple physics.
- As mentioned in post #1, the room will be about 13 x 40, after one wall is removed.
- The only outside wall is one of the long sides.
- The ceiling is just under 8' high.
- The windows along the outside wall are too close to the ceiling to allow mounting a wall unit.
- The ONE area where the wall is long enough between windows is over the back patio.
- That ONE area is only about 10' from an end wall, meaning that air distribution to the other end of the room will be minimal.

My thinking might be a bit delusional, but I am under the impression that a cassette unit near the middle of the room will only have to blow a bit less than 20' to each end. If the air flow can be directed along the ceiling, it should make it just fine.

Although I have seen several wall units in places that I have visited, I have not been in these locations long enough to evaluate their finer points. This will be my first unit at home. I am also looking at putting two units out in my shop, but neither of them would be well-served by a wall unit, either.

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OK I understand the situation better now.

Sure, the mounting position for the wall unit is not great. However, I'm not sure a ceiling cassette centered in the room would perform better. They shoot down (at a certain angle, but still..) and, in my experience, they don't perform quite as good as wall units.

What is the room used for ?

 

[dave*99]

The wall units have an oscillating louver. They sweep the airflow up down left right.

 

[Steve W.]

What is the room used for ?

One end is the “family room”, which is also our home theater. The other end is dining room and kitchen.

The cassette would be between the “rooms”.

Back to the question posed in my post #1, why would one of the “professionals” suggest putting it at one end, rather than the middle?

The wall units have an oscillating louver. They sweep the airflow up down left right.

Quite true, but when the ceiling is less than 8’, that airflow will sweep right across my chest and belly button. (I’m just a bit taller than “average”.) I don’t have to duck under the ceiling fans I have installed in the house, but they all DO have shorter chains on them to select fan speed.

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[dave*99]

On my wall mounted mini-split, the louver can be set to direct airflow upward to ceiling - yet still sweep left and right.
You would have less air directed at bodies than a cassette would provide.

I can see why you are looking at a cassette. It really looks like the right unit for your room. But....

My wall mounted mini split is in a 24x28 room with an 11' ceiling. It seemed like a cassette would be great there. So I asked the HVAC company.
This is a reputable family owned company with a stellar reputation in our area. And the house was new construction - so there were no installation issues.
I asked about cassette. The owner of the company, said "Naw they are expensive, a pain to maintain etc. - you won't be happy with it."
During the selection phase of many items in the house build, I often asked the tradespeople what they would do if it was their house. Taking their recommendations worked out very well.

I had a mini split installed in a long narrow room at work. The installer said the short wall was the best place.

 

[justinjoyal]

Back to the question posed in my post #1, why would one of the “professionals” suggest putting it at one end, rather than the middle?

Shorter lineset, less cost for him, more profit ?

 

[Steve W.]

Nope. The outside unit would be closer to the center location.

Looking over all the quotes I have received for this installation, I am more and more inclined to do it myself. I have a friend that is a licensed HVAC tech that can help with the pressure test and vacuum drawdown, so that might help with any questions about warranty.

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[brit vet]

Air flow patterns are much better with ceiling cassettes than wall mounted units however with your room width being quite narrow and long you will almost certainly suffer some short-cycling with a 4 way blow cassette as air bounces off the narrow walls. A two way blow cassette would make more sense and do away with any short cycling risk. All maintenance is done from below as with all cassette type fan coil units.