Thinking about installing my own retrofit AC system-with some help from real HVAC guy
I just bought a 1920's house which has over 4800 sq feet on two floors, with a small bedroom and large open attic on the 3rd floor. I just had an estimate for getting a Unico system installed. For a single system where the air handler (I think I'm using the right terms here, I'm still learning about HVAC) would be in the attic and the 5 ton condensor would be mounted right above the attic on a large section of flat roof, they want about $25K, IF they install during their "slow time" of the year, more if I want it sooner. They would run the ducts around the attic, with ceiling outlets on the 2nd floor and run through several closets to get to the 1st floor, although they wouldn't be able to get outlets in every room, but the guy said he thought it would still cool the 1st floor just fine, although I'm a bit skeptical. Its a big house with some big rooms that would rely on air coming from other rooms, I just don't know if it would be really what is needed.
I did some more research and came up with another idea that I think would be much more ideal for a few reasons. This setup would have two systems, one in the attic for the 2nd floor and the bedroom/bath on the 3rd floor and a separate system in the basement -the house has a full basement that is pretty much wide open, I could run ductwork just about anywhere.
I have tackled some pretty big home renovation projects over the years and I have a couple of guys I know who are licensed HVAC techs that I could get help from where needed, like hooking up the equipment, etc. I'm just wondering if anyone here has done anything like this before? My plan would be to run the same type of insulated, flexible round ductwork that Unico uses, that work I could diy and then I'd have one the the HVAC guys I know come and hook up the equipment and get it going for me. I see that there are several places on the net that sell HVAC equipment to the general public, or I might be able to get one of the HVAC guys I know to order the equipment for me, too.
I install the unico high velocity sytems, about one or two a year. I quote about 5 or 10, mostly due to cost. As you see they are more expensive than a conventional system. They typicaly cost 20% to 30% more than conventional systems. This is due to alot of the duct work must be purchased from Unico and it is not cheap. Each supply vent will cost the contractor $120.00 to $150.00. this is cost of take off, register and there flex duct (all must be bought from them and is unique to them). you also need 6 per ton. Those 6 have to be no more than 10 ft or they loose capacity and you need more than 6 then.
I most offen look hard at can i install a conventional duct system before quoting Unico. You are correct that I would install a conventional system in the basement and the unico for the 2nd & 3rd floors (if that is all that you have space for).
Your first step would be to have a load caculation on the home. There is no sense guess size and spending this much money on a guess.
Most lic techs you mentioned may not be able to do a load caculation. They may also not beable to design a system. Personaly I think it is harder to design a unico than a conventional system. I would not recomend it to a homeowner. If you do decied to install it yourself: try to find a master willing to design it and guide you through its installation.
Thanks for the reply! I'm sure you have a good point about the design of the system, that it should be done by someone that really knows what they are doing, especially considering that its a pretty big house with a lot of rooms over 3 floors, I'm sure there are a bunch of different ways to do it, some being smarter than others. The more I think about it, I'm leaning towards just having someone do the whole thing and I have time to think about it too, because our air conditioning season will be over in another month or two here in the upper midwest, although this has been one of the hottest summers I can remember! So, I would probably be looking to get something done after the holidays and before next summer at some point.
Also, I think I would have more than enough room for "regular" duct work in the attic, its a BIG open attic with lots of room, I don't see why we couldn't run regular ducts.
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