I am in the planning stages of a 37 unit townhome project just outside Nashville TN, because of the size of the lot and the look that we are trying to accomplish I was hoping to install the A/C condensors on the roof. Most likely the Bryant Ultra Compact Preffered Series. The picture is of a development outside of Dallas TX but I do not have any details such as how the access works or how they framed the opening. Just looking for any advice as to what may be some of the potential problems.
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Replies
Noise, vibration, service access. Efficiency may suffer if the utility "well" in the roof is to deep, blocking airflow.
Wait... Those blobs on the top are the AC units?? How ugly, even for cookie-cutter apartnemts. Can't they be hidden behind the mansard?
Edited 7/30/2007 5:08 pm by DanH
The Bryant unit that I was looking at is extremely small, less than 15" deep and it can be as close as 4" from the wall. They are also extremely quiet. I was thinking I could disguise the well with iron railing. I am open to other ideas there is just no where to put them on the ground.
I wonder if there isn't some way to do "community AC" with usage billing, vs having lots of tiny units. Would have to be more efficient.
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. --Benjamin Franklin
Talk to whoever is going to provide your service work on those units. Not the owner of the HVAC company, but the guys that have to climb up there with a bucket full of tools, gauges, freon tanks, hoses, etc.
Now think about them working safely and efficiently. It is not going to happen in the units in the photo or anything like them.
Like Dan suggested. Flatten the roof out and put a mansard around the edge.
Dave
How ugly, even for cookie-cutter apartnemts
Shoot, around Dallas, those are "upscale" (you can ask the leasing agents). They have fancy iron railings, and garages, too! (that's probably another $750 the month right there).
The fact that the property owners stuck a/c units where they can barely be serviced will be balanced by the fact that they probably bought the least-sized, smallest-priced unit anyway. (Probably sitting on the cheapest possible shingle, too.)Occupational hazard of my occupation not being around (sorry Bubba)
This will not be a cookie cutter development. The purpose of this is not to reduce cost or make it difficult for the HVAC contractor. As I said earlier the units that I am hoping to use are extremely small and efficient. I am planning on having amble room for service work, a wrought iron rail for safety and to help disguise the look and access from the attic space. It is not going to look anything like the picture I posted from Dallas the picture was to just give some idea of the concept.
Builders in western CO are using rooftop-units (RTUs), even on expensive homes. They combine heating and cooling (gas furnace), but boy are they ugly. Builders like them because the lot set backs are so small nowadays a regular condenser would literally be under the neighbor's window. The big box usually sits low enough on the roof to be hidden from the front elevation. Who cares how it looks from the back, right?
Have you considered installing Watersource Heat Pumps? This could be done with one "primary" loop with it's water pump(s) that the landlord or association would maintain and each tenant would be resposible for their own utility bill and maintenance of their own heat pump. There would be no equipment on the roof outside on the ground. There would probably be green points for this to help offset the additional cost.
The Primary loop is the one that would run ouside through the ground and through the building. It contains a water/glycol mixture and takes the place of an ouside unit for a heatpump. This is a lot cheaper than having individual loops for each condo. There is just the usual water treatment and pump maintenance with this portion of the system.
Each condo would have it's own ground source heatpump inside unit that would tie into the primary loop with a secondary pump instead of going ouside on it's own. This is the part that requires more frequent maintenance and repair.
In any area that subscribes to the IBC/IMC, unprotected roof installations would not be legal. They obviously don't follow that code there, but check which building codes apply where your project is to be built.