Advice on DIY house a/c replacement

One of my A/C compressors took a dump on me. The HVAC guy quoted $4000 to install a new 2-ton AC unit (condenser, coil, etc). Now, ordinarily I'd hem and haw and probably just drop the $4k. However, I have three total AC units and one is just as old as this one (19 years) and is even bigger so would be more expensive, so the skills I pick up doing this one would translate into an additional savings down the road when I do another one. In looking online, it looks like I can get a Rheem 2-ton 16-seer for $1449 with coil. What I've got is all Rheem (furnace, ac) so it would be nice to keep to Rheem. In addition to that I need a line set. I have a good vacuum pump from working on vehicle a/c systems. I would need a gauge set that was r-410a compatible. I would get a Yellow Jacket flaring tool to do the 45 degree flares on big lines (gas line is 3/4" - my flaring tool does not go that large). All told I'd still be less than $2000.

Has anyone else done their own house a/c install? Am I forgetting anything? Are there any special challenges to it?

Bringing this up only because it sounds like it would make a big difference in your house: what became of the minisplit discussion? Seems like it would make more sense for your house. 

Otherwise im no help here, unless you want to buy one of my window units 

I’m still considering the mini split but need ac working (this one serves the kids rooms) and am having trouble getting a quote from my vendor on the mini split install. Also not sure I can come up with time to do a mini split install myself while repairing what’s there is more feasible. 

Yup - I have been in your position a couple times before and took the diy approach. The one advantage I had was having relatives in the hvac business so I could get the units wholesale.  Incredible the markup and labor charge for residential hvac. (Yes - I know those folks have to make a living as well).

Did one with the old Freon and one with the newer refrigerant. The newer used harddrawn copper for lines which is not fun to bend - especially in the tight radiuses. The was not fun item number one. Be careful to not crimp the line. Reason for use of hard copper for lines "is the higher pressures" used in the newer refrigerants. Also the unit I installed no longer used flare fittings for the lines. They require soldering - not the typical propane heated soldering that you may be used to. Instead a harder solder is required. I used silver solder and ox/acetylene torch (did not have an acetylene/air torch).  Propane wont cut it. This was not fun item 2 for me. If you over heat the copper, it wont solder and ruins the copper - so you cut it off and try again. Fortunately for me - got it the first time. There is some softer solders that do the job and are part silver and easier to use - dont recall the name a the moment. Perhaps the newer models  have gone back to flare fittings - that would be nice. Might want to check to be sure so you know whats ahead.

Learned another lesson the hard way. Pull a good vacuum once you get the lines hooked up and let it sit for some hours. If your gauge is still showing the same vacuum - you're good to go. I was tight on time and only let it set a few minutes - found out later there was a small leak (but not a solder joint).  Only add the refrigerant to the low side line (may need to invert the gas bottle is get some liquid but watch your pressures closely).  Just be patient while you add the gas. Do some research on what pressures you are looking for given the refrigerant you are using.

And that foam on the return line - try not to mess it up as its there to keep the sweat from dripping on whatever the lines runs through. Those lines love to sweat in the humidity.

I have done much tougher jobs - but that silver soldering sucked.  Probably what adds to the fun is the 90+ degrees and 100 percent humidity while you do the work. All told you will save a ton of dollars.

And you know you may not have to replace your A coils in the furnace or air handler. And also used to be able to get replacement compressors if that is what crapped out. Have helped do this once and that is a crappy job.

Monday I am having a hvac guy visit one of our units. Fearful of what he might say. Probably  will have silver soldering nightmares but I still cant stomach the install prices from the pros. Maybe time to teach my son about AC units (which means he does it, I watch).

DIY installation may depend on if you are allowed to purchase and use refrigerant where you live.