Central Air install: DIY or pay a Pro?

[gb99]

With the new addition being added to the back of the house, total living area will be about 2600 sq. ft. (~1650 on 1st floor, ~900 on 2nd where the bedrooms are).

Since we're doing all this construction work, it's time to lose the window A/C units and get a central air system. I'm open to traditional ducted, slim duct mini splits or ductless mini-split (or some combination).

Thinking of an electric Mitsubishi slim duct system in the attic to supply the 2nd floor. Then another same system for the core of the 1st floor and a mini-split for the new 1-story addition on the back of the house.

I live outside of Boston MA and initial quotes are in the $30-40k range. I don't have a trust fund and have done multiple full restorations on car A/C systems (evaporator out, vacuum, Nylog the o-rings...the whole 9).

Should I pay the pro or give it a go myself? Appreciate feedback from those who have done it themselves. Thanks!

P.S. I'm going to lay PEX for a radiant floor heat system in the new 1-story addition and garage slab. Not sure of the heat source for this yet.

 

[99LeCouch]

Look up any MA specific laws or codes on HVAC stuff. Can't install your own gas furnace, has to be done by a gasfitter.

Also, brazing and nitrogen purging while brazing needs lots of spendy equipment.

 

[jjrbus]

I am sick to death of so called pro's here in FL. Fancy white trucks, nice uniforms and really do not know what they are doing. There are a few good ones around but there is a boom here and the good ones are booked many months in advance and not looking for more work!

So I did my own mini split install. However I am retired and enjoy learning new things and spent many hours researching on the net.

Diy people can do a far better job than the average hack trying to make a living if they put their mind to it.

I had a few tools and a bit of auto ac experience. Still had to spend another $600 on tools to be able to do the job correctly.

If you have the time to do the research and footwork, I say go for it. My opinion and worth what you are paying for it.

 

[G-ManBart]

If you go with a Mitsubishi unit(s) the warranty is different (significantly) if you don't have a licensed HVAC tech do the purge/hookup. I used a Mr. Slim with heat pump for my shop building, and added another Mr. Slim to cool the loft in our house. I ran the electric, hung the mounting plates, mounted the exterior unit, etc before the HVAC techs came and did the final bit of installation so it wasn't terribly expensive. They still pulled the hose sets, purged the lines, did the final electrical hookup, etc, so there were two guys working at least half the day, but it saved me a lot of money.

That actually saved me even more. I can't recall what part failed on the one unit, but it was a fairly uncommon failure that led to a compressor failure. That happened less than a year after the installation, and I would have been out a boatload of money if I had done all of the installation myself. As it was, the techs came out, called Mitsubishi, did some troubleshooting while on the phone, put a claim in and all the parts were free. I had to cover the service calls and the tech's hourly rate, but that was just a couple of hundred dollars give or take. It would have been far worse if I had done everything myself.

 

[yeldogt]

Factor a tad over 4k per head for Mitsubishi hyper heats w/ eye -- I was in the 14k range for a three head system. My new 2 head and another single head is about the same.

Once you get into the ducted mini-splits -- things do change a bit. The units cost a little more and obviously you have the duct work .. they require some engineering to make sure the ducts are correctly placed and sized.

My zoned Carrier system w/ new metal ductwork is just over 30k -- So your prices are in line.

You can pick up the lower end units for good prices -- but the higher end units do command higher prices .... so the installers can actually make more installing the cheaper stuff.