My reservation would be congruent to Bill Parcels statement "if I am going to cook three dinner,I buy the groceries. If the system does not work to expectations, who its going to be responsible?
I'm new but this caught my eye. The OP said the installer he would like (I assume if the installer can buy the equipment, he is a licensed contractor dealing with heating and cooling) doesn't do the design. So what's wrong with getting a separate design?
I'm asking because I had contacted a member of the ACCA that works as a consultant to the industry. From what I am reading here it would seem that you assume every installer is capable of designing the most efficient system for the situation.
Can everyone who installs be that good?
From talking to those that have given me an estimate (2), I already see that this science is not exact.
And, to the OP, even though this is an old thread, my quote for 1300 sq ft single story stucco SoCal house was $950.
I am not assuming anything. I am sure that lots of times, two separate companies have worked together and it works out alright. But, mistakes happen, and there is potential of "he said, she said".
If I design a system poorly, and I do the install, all liability is on me. If I hire a guy to design, and the designer messes up, again, it's on me. But, in this scenario, I install, and it passes code, yet the design is wrong, who is going to be at fault? Thats why I was using the dinner and grocery analogy.
Being a newbie here I certainly want to mind my manners. But I just finished reading Flash's baby room thread. All I could think of while reading about all of the possible solutions is that someone with a lot of knowledge and good software might have been able to pinpoint the problem. It seemed obvious that whoever designed and installed the defective system didn't do the due diligence.
I'm not sure myself that the issue is closed regarding using a specialty consultant and letting the contractor follow the prints. I don't see how there is a problem if the prints are followed to the letter.
In my work as a contractor I sometimes had to follow what a structural engineer indicated. If an inspector didn't like what he saw then a change order was executed to make corrections. Sadly, I never saw an engineer fund those corrections. I don't have a whole lot of respect for engineers away.
Seems a stamped set of plans will have a T24 page in it(in California this is a requirement on that page you can collect the heat gain and heat loss cfm for each room.
I always install systems in the same environment and can size rooms by doing a walk thru,
each fau offers a cfm rating as 400 cfm per ton = about 500 feet per ton
each unit needs the correct return ducting to allow the correct static pressues which allows the compressor to run at specfic ranges of head pressures.
Long story short...any a/c guy can size a system if that guy has been trained well.
And any hvac guy will give you a start up report from his imanifold...
B.T. Since you mentioned oversizing, I have a question. Do you guys design for latent heat removal (humidity)? Or sensible heat design?
It seems as though you don't want too big of equipment to deal with latent heat. But whe it gets real hot (95+) you also have to deal with sensible heat.
Depending on what you mean by this, I'd undersize or oversize the main unit and then fix the seasonal and day/night discrepancies with small units that heat, cool, dehumidify or humidify.
But, ASHRAE will tell you there are many constraints on how to get "comfort".
No such thing as one size fits all. Some people want the home meat locker cold wheñ its 100 degrees out. Some don't like ac. So many difrent factors in determning comfort.
True. But with standard efficiency equipment parts are readily available, and one isn't required to purchase o.e.m. parts at a convenient markup.
Iam not hating on modulating equipment or variable speed motors in the way they operate. Its just a homeowner of modest means can be put in a vulnerable situation. And, all savings from the utility bills are negated.
I agree. The consumer has to be educated on the HE equipment enough to make the decision for themselves. I see so many just say "if we replace your old oil boiler with this new 96% efficient boiler, you'll save $$$$$$ every year." Then they try to push oversized equipment that defeats the purpose of upgrading.
I don't have a problem with the availability of the equipment. I do have a problem with the proposed mandated minimum efficiency equipment.
Soon, the 80% gear will likely be 86ed, and many homes were built in a manner in which running a new flue venting system (including the condensate disposal) can become a major expense, again, negating any savings from the bill.
Lets face it most people aren't interested in mechanical efficiency, it's $ efficeincy that interests them.
I don't dispute that. However, if there is a shortage of ___ it will be priced accordingly. Since we have such shortages, why aren't gas stations required to offer alternative fuels than simply gasoline?
If you do the Netflix streaming thing, check out the movie titled Pump. Its a documentary on the gasoline monopoly. It was an eye opener.
Its an extremely tight constructed home. They did have a mini split installed for the master bedroom because they like it extra cool at night when sleeping(70 and lower sometimes). But stopped using it because the central 2 ton cooled the home and master bedroom better then the mini did the master(kept the humidity down better).
Yes, its foamed. Don't need a big A/C if the heat can't get in.
One of the biggest problems with foam insulated homes. Is HVAC contractors not understanding insulation and air tightness effects on a home. Many foam houses have A/C systems 3 times as big or more then is really needed. And much higher electric bills then they should have.
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