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Competency in the HVAC Industry

bongo30 | Posted in Mechanicals on

We are building a new home in Long Island and had Manual J done hoping to install ducted Mitsubishi air handler units. As per Manual J, we need approximately 12k BTU cooling load per floor (2 floors, 1400 sq ft each). Every Mitsubishi contractor we spoke to is refusing to install units of that size, saying we need at least 3 ton per floor. What shall we do next? This is coming from Mitsubishi Diamond Preferred Contractors. I have reached out to at least 10, and most don’t even call me back once we tell them what we need. Why is the industry so behind on the recent developments and resisting the change? I feel defeated as we will not be able to find someone to install the system as designed. Any word of wisdom or advice?

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  1. capecodhaus | | #1

    I don't have anything positive to add. My personal experience with Mitsu Diamond Preferred Contractors in Massachusetts was only ok. The salesman was good at listening, made suggestions and was personable. The first attempt at install they showed up with a damaged outdoor unit and offered me a dent n ding discount, which I refused. The installers, a couple of guys 25-30 years of age. One didn't have a dust pan to clean up after himself, the other guy struggled to use a hole saw properly to make access for the line set. The biggest loser in the bunch was guy number three who does the refrigerant work. He managed to leave his vacuum pump on my lawn over the weekend after calling it a days work. The Hyperheat did perform well.

  2. mgensler | | #2

    If you've found this website, you probably know more about certain things than HVAC contractors do. Dramatic change is very difficult because the way they have been doing things for decades works for them. You can offer to sign a waiver with contractors if they are hesitant to go with your plan. You can also have a mechanical engineer do the calculations and spec the equipment. This worked for us. I did the fuel consumption based calcs and the manual J. I spec'd the equipment and then hired a mechanical engineer to design the ductwork and put the equipment on the plans. The HVAC contractors accepted this as they thought everything came from the engineer. If you do this, make sure you double check the work of the engineer. They made a couple of mistakes on our project.

  3. PBP1 | | #3


    Maybe it's time to go "environmental" on them, I had a HERS Rater involved, according to city code I needed a HERS score. Fortunately, my HVAC guys and the HERS Rater got along fine, they had worked together previously with a good relationship. It was actually the plumber that tried to sneak in some back-up heat. I opted to go without - and all is fine, even when below zero on a "right-sized" 28.6 kBTU/h hyper heat in CZ6 (2100 sq ft) design temp -1F.

    It is in your best interest, for your $ and time invested, to get as low of a HERS score as possible for increased home value (lesser energy demands). I checked and noticed a few in Nassau County/LI, one stating:

    According to, “Government agencies such as the Department of Energy (DOE), Department of Housing and Urban Development (HUD) and the Environmental Protection Agency (EPA) recognize the HERS Index as an official verification of energy performance.”

    Maybe it's time to adopt contracts where there is a plus for the HVAC contractors to get it right for client and environment. Or simply to let a HERS Rater (or other energy consultant/engineer per mgensler) determine load and have HVAC merely install.

  4. kyle_r | | #4

    Can you just bid out the ductwork? Your builder should be able to get the electrician to do the electrical. Buy the units online and get your builder to give you a guy or two to help set the units and run the line set. You should be able to hire a local HVAC contractor to pressure test and vacuum the line set. You won’t have a warranty, but I’m not sure how valuable those are anyway.

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