Ceiling cassette unit in a Cape style home

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  #1  
Old 06-16-11, 09:19 PM
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Ceiling cassette unit in a Cape style home

Hello all,
I'm looking at different options for a mini-split system in my house. For a number of reasons, two 9K Btu ceiling cassette units would probably be the best choice for my top floor. The top of the units would be in the attic crawlspace.

I'm concerned about the unit's "backside" in that unconditioned crawlspace. Won't I lose a lot of cooling from the crawlspace (and the top of the unit) heating up in summer? The unit has a condensate pump in it. Will residual condensate freeze in winter and damage the pump?

Lastly, the installer wants to run the condensate line down the inside of a roof rafter, drill a hole through the fascia board and into the rain gutter, and drain the condensate out that way. Is that kosher/Code?

Thanks in advance for your comments,
Doug
 
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Old 06-16-11, 10:50 PM
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Hi,

I have a cape and would consider something different then you suggest for your home. That whole cassette thing you describe does not sound appealing.

Do you have a basement?

IMO I would put a regular unit in if you can and lose a closet on the first floor to run ducts up to the second. If no basement then a self contained unit would be the next choice. My crawl opening will not fit a unit.

Like this.

Goodman 13 Seer 2.0 Ton Straight Cool Package Unit :: Self Contained Package Units :: AC 4 Life, Inc.

I am not an A/C guy, but when I was figuring for central air my A/C buddy said a self contained would be best and to lose a closet because 4-5 ducts would need to be run.

He wanted to put two or three returns up there. Its like being in a attic in the summer time.

Well the other thing is cost. Ususally capes are small and window units work well. I have the smallest cape ever made, and window units in my case are cheaper to run. ( I think)

Two 5000 btu units in each upstairs room @ 550 watts each, and one 10,000 btu @ 900 watts cools the whole downstairs. On that 101f day it never really shut off ( Compressor) and kept the house at 82-85F.

But you may or may not be concerned with saving electric, and just want it cool.

Well just some comparison for you. Hope it helps.

Mike NJ
 
  #3  
Old 06-17-11, 04:45 AM
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how are you going to use a cassette somehow attached to the crawl? I dont get that one. As far as the condensate, that should be fine or the other option is to pump it to a plumbing vent stack.
 
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Old 06-17-11, 05:47 AM
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Hi Mike,
Thanks for the response. A little more about the house - 3 floors (walk out downstairs, main floor, top floor with full dormer off the back), all ceilings finished with sheetrock, open floor plan (no closets to speak of, only one coat closet on main floor), open stairwell (all the heat/cold goes up/down), baseboard electric heat (no ductwork), good insulation (4" fiberglass plus 1" aluminized foam in the walls, 8" fiberglass in the ceiling). Almost all the windows are casement style, so I can't install window units. I do have a window on the top floor that I put a 12,000 Btu window unit in, and it almost handles the entire upsatairs. There is no place to put a large air handler in the attic crawlspace, although I might be able to squeeze a ducted minisplit unit up there.
I'm leaning toward wall or ceiling mounted minisplits because they're designed to work without the ductwork. Also, filters are accessible without having to climb into the attic.
For the upstairs, I wanted two units because I plan to split the area up into two rooms. In one room, there is one area I could put a wall mounted unit, but this would put the linesets three stories up outside and not easily accessible. The lines would be over a cantelevered deck and an awning, not easily accessible by ladder. Plus, the lines would run the entire length of the house, turn a corner and run the length of the side. The lineset would wind up probably be more than 80 feet in length. It would also place the unit in between two bumped out closets which would tend to channel the air flow across the room. In the other upstairs room, I could use either a wall or ceiling unit, the decision is purely aestetic.
On my main floor, there are only two areas large enough to put a wall unit - directly over the fireplace or next to the stairs. There is not enough clearance over the windows for a wall unit. I'm leaning toward putting the unit next to the stairs. It's probably the least ugly of the choices, although there could be airflow problems and the linesets would need to be hidden somehow on the outside.
My lower floor will get one 7000 Btu unit. No challenge here - there's only one place on the lower floor exterior walls where there is enough clearance to fit anything. Plus, it's the only unit I could put on the one remaining port on the compressor. Most likely, this unit would end up running in "Dryer Mode" most of the time.

Thanks,
Doug
 
  #5  
Old 06-17-11, 09:18 AM
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HI,

Well you have a basement. Not considering putting a unit down there? Ducting the first floor should not be an issue. If you can get ducts from the basement, through a bedroom closet up into the attic you will be golden.

Have you asked neighbors with similiar homes what they have. All the homes in my neighborhood have similiar homes and my wife and I always get tips when we see how other homes are.

All those linesets also. I thought about those mini splits. to much stuff on the side of the home for me. And a big eyesore on the wall. Although window units are not that pretty either.

The A/C guys will give you good advice. I was only giving you something to campare to.

Mike NJ
 
 

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