Hey guys, I just got here from another non friendly site. I have a 10 year old house with a piece of crap York unit that has finally kicked the bucket. I have had to replace several components on the furnace over the past few years and now the compressor just died. The unit is a 70,000 BTU furnace with a 3 ton condensing unit. Goodman Gas Furnace Air conditioner Systems, Buy Direct from ACWholesalers.com, Free Shipping. I am ordering a Goodman 18 Seer, dual stage compressor, Dual Stage furnace and dual stage blower. I am also going to spend the 300 for the Goodman thermostat which is more than a just a thermostat. I've been doing some research the past 2 weeks now, and wanted to share with you what I have found. For those of you with older systems, they use R22, a refrigerant that is being phased out, no units being sold after 2010 will use R22 and production of R22 will cease by 2020. Why is this important, well some A hole HVAC people will try and push an old R22 system on you for a 'good' price. The newer stuff to use is R410 and is Environment friendly, I believe it lacks the chlorine, at least I think it was chlorine in the R22. I was going to replace the outside unit, and after some research, the high efficiency units out there now can't really be controlled by your older inside equipment, the newer stuff is a dual stage compressor, dual stage burner and multi speed blower fan, along with some other valves that control the flow of refrigerant to reduce cost. I have a gas furnace, and will be installing a heat pump A/C unit and a new gas furnace as the backup source. This is the most efficient setup out there other than geo thermal. My original unit wouldn't keep the house cool, at 95+ degree days, the unit would run for 12 hours straight and not get below 74-76 degrees. I finished the basement and added a laundry room above the garage and it got even worse, so I upgraded to a 4 ton unit, 3.5 ton probably would have been good, but the model I wanted only came in 3 or 4, so obviously I went with the 4. I will have to enlarge some of the ductwork down stairs in order to accomodate the higher flow, and I actually opted to have a friend do it as I hate sheet metal work. You could always place a quick ad on craigslist if there is a part that you need help with. There are many people out of work right now and you can get someone to do a side job cheap. A friend of mine actually does new house duct work and also did some houses in my development so he is going to do that. I also opted to have a technician help me with a few things, I placed an ad on craigslist and got a service tech that is going to evacuate my old R22 system. I don't care about the EPA or law, but venting R12 or R22 to the air is simply bad for the environment and not a good thing to do, yes I could do it and no one would ever know, but really, this guy charges $65/hr for service, so it is money well spent in my opinion. He is also going to do the leak/vacuum test prior to me firing up the new system. I may also have the technician braze the lines as if you do it incorrectly, there can be some crap built up on the inside that can damage the compresor. As I said, a few beans for some help is money well spent. For those looking to go the cheap route which is ok with me as we are all in the same boat, if you replace just the outside unit with a newer unit, R410 requires a higher pressure, approx 50% higher than R22, the coil and lines inside the house depending on condition may not be able to handle that. In theory, you could pressure test it and clean out the lines and coil with some special equipment so that the R22 and R410 doesn't mix, but honestly, after looking at that, a new coil and lines aren't really that expensive compared to dealing with that crap. As I said, I am doing a majority of the work myself, but you should know that I have a degree in electronics engineering, I am highly mechanically inclined, I have framed houses years ago, done plumbing work, electrical work, repaired cars, built motors etc. I am in the computer field now, but still have a few project cars. I have all of the common hand tools along with grinders, welders, torch, air compressor, assortment of air tools, not that most of that will be used for this install. I will have someone with the 'know' look over my work, test and check things out before I fire it up, but I think a majority of the 'grunt' work can be done by a common guy with common sense. In my case, I am not revamping a house that is 100 years old, I have an outside unit, I'll run new lines inside, so basically look how it is done and replace what is there, I don't think that much talent is required to do that along with bringing the unit down a flight of steps. I am going to move the thermostat though, this will require me to run new wires for it, but that is going to be simple as to the common area I want to move it to is right above where the unit will be from the basement. Also, for those of you that go with a heat pump option over your regular gas fired unit, a new thermostat is required no matter what system you buy, as it needs to be able to switch between the two. I will update this thread more as I go along, I hope it helps someone make a better decision and not allow some of the so called 'pro' sites discourage you in your endeavors. I am NOT a professional by any means, other than the numerous repairs that I have done on my own system, I have no experience with HVAC.