NO1SMAD
Well-known member
I have a two family that I need to replace the HVAC systems (never had air before), what are the pitfalls and what should I be looking at? What is the best source for systems?
Any experience in DIY HVAC
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Ohmthis
Well-known member
Hvactalk won't give a lot if any diy advice. I will just give the pit falls. It needs to be sized correctly both the equipment and the ductwork. This requires a couple of calculations a manual j and a manual d. The j for the equipment and the d for the ductwork. Hopefully you can find a contractor to do this for you. Once you have the calculations done you can get your materials. Ask on here where people have been getting their equipment, I work in the indusrty so I use the local supply houses. I doubt yours will sell without a license, but it doesn't hurt to ask. Use the duct layout to install your duct, if you have never done it before it may be best to hire that out. You can use the equipments paper work to get most of the info the manufacturer wants the way its Installed. Hire out the connections and final startup. I will warn that the system is only as good as its install. This isnt out of realm of the diyer, but the upfront costs are not just the materials. There are permits, tools(several special tools are needed), fees for hook up and final commissioning. Good luck and keep us informed.
Falcon67
Well-known member
NO DIY - seriously, you will get kicked off the site. Don't even try.
"2. Do-It-Yourself (DIY) - not here.
This site is for industry professionals and folks seeking HVAC/R advice and knowledge. Please do not ask for step by step instructions on purchasing, installing or repairing your own equipment. This is our job and our livelihood. We are generous, but not to a fault. "
http://hvac-talk.com/vbb/showthread.php?853582-Owner-Assistance-Rules-Must-Read-Before-Posting
I'm strong advocate of DIY on almost anything. Not on HVAC. Would not do my own and I'm a retired Professional Engineer. I've done all the calculations on heat loads, refergerant selection, pipe sizing, duct sizing, fan calculated HP - all of it, and I would not touch it. If you don't have the knowledge and background, this won't end well for you.
Is it rocket science? No. But you just don't know what you don't know. Every mistake you make will show up. Any item oversized and undersized will bit you - even if you get it all put together correctly. Leave it to the guys who do this daily. They make enough serious mistakes themselves.
Is it rocket science? No. But you just don't know what you don't know. Every mistake you make will show up. Any item oversized and undersized will bit you - even if you get it all put together correctly. Leave it to the guys who do this daily. They make enough serious mistakes themselves.
HVAC requires you have a wide skill set and the equipment to back it up. AC units have much higher working pressures and more stringent requirements when it comes to brazing the lines together for an example. Unless you have an insider in the business you won't be buying the equipment or finding the needed info.
You can educate yourself as to what a good install includes and then find a contractor that will do it to that standard.
For the brazing the lines together as an example the lines need to be purged with an inert gas while the lines are being brazed then a deep vacuum pulled.
Like a lot of things HVAC is getting much more complicated than it ever was before and close enough doesn't work.
You can educate yourself as to what a good install includes and then find a contractor that will do it to that standard.
For the brazing the lines together as an example the lines need to be purged with an inert gas while the lines are being brazed then a deep vacuum pulled.
Like a lot of things HVAC is getting much more complicated than it ever was before and close enough doesn't work.
oilslick
Well-known member
Without knowing your skills and what tools you have available it hard to say if I can recommend you tackling it. I did my own new house but I am familiar with threading steel pipe and silver soldering,I never purged mine 10 yrs ago with no I'll effect yet but I hear 410 systems are more sensitive. Goodman makes a descent product and matched components are available online. I personally run a 5 ton evap with a 3 ton compressor and it works great and runs cheap, my dad switched his to a setup like mine and saved on utilities too! It's not rocket science ,as long as you use common sense and have a standard setup with good ductwork and plenty of return air. High efficiency furnaces and ac require a condensate drain so plan to put in a pump if no access to a drain close by, good luck.
mygarageone
Well-known member
I highly disagree about Goodman being decent Equipment.
I see a lot of it around here and it's because I have to service the stuff.
But it is cheap and that's what many people are after.
mayday0017
Well-known member
Personally I wouldn't consider paying someone else to install a new system for me.
I have been around several "Pro's" and there are 3 categories they all fall in.
1. About 50% of them think they know the right way to do things and do it that way (These guys live by the theory it turns on and works and that's all that matters).
2. About 30-40% of the pro's make up the next group. They know what a manual J is they know people say it should be used. They know it is said you should have a shielding gas while connecting lines. They know all of the "Right" things to do but they are either too lazy to do it (because you can't see if they did) or they think they have a work around such as every 1,000sqft needs 1ton unit.
3. About 10-20% of the pro's out there make up this group. They take an engineer approach to the system. Follow manufacture design requirements and recommendations. They follow publications produced by engineers. They learn and absorb and do everything they can correctly. These are the guys I would let work on my system and maybe even install a new one for me. The only problem is, in order to know you got one of these guys you have to know almost as much as they do so you can ask the right questions and know when you are getting the wrong answers.
So with all of that being said you can do the job yourself better than the first 80-90% of pro's out there if you spend a month or so doing research and reading everything you can. Buy a little material and practice making connections and not only pressure test them but look inside the joint to see if your shielding gas kept things nice and clean like it should.
If you really do your research and you take your time I truly believe you can do work on par with the individuals in group 3. I would recommend paying someone to design the system doing a manual J and manual D if you know you got these right the rest is just putting the pieces together following the manual.
I have been around several "Pro's" and there are 3 categories they all fall in.
1. About 50% of them think they know the right way to do things and do it that way (These guys live by the theory it turns on and works and that's all that matters).
2. About 30-40% of the pro's make up the next group. They know what a manual J is they know people say it should be used. They know it is said you should have a shielding gas while connecting lines. They know all of the "Right" things to do but they are either too lazy to do it (because you can't see if they did) or they think they have a work around such as every 1,000sqft needs 1ton unit.
3. About 10-20% of the pro's out there make up this group. They take an engineer approach to the system. Follow manufacture design requirements and recommendations. They follow publications produced by engineers. They learn and absorb and do everything they can correctly. These are the guys I would let work on my system and maybe even install a new one for me. The only problem is, in order to know you got one of these guys you have to know almost as much as they do so you can ask the right questions and know when you are getting the wrong answers.
So with all of that being said you can do the job yourself better than the first 80-90% of pro's out there if you spend a month or so doing research and reading everything you can. Buy a little material and practice making connections and not only pressure test them but look inside the joint to see if your shielding gas kept things nice and clean like it should.
If you really do your research and you take your time I truly believe you can do work on par with the individuals in group 3. I would recommend paying someone to design the system doing a manual J and manual D if you know you got these right the rest is just putting the pieces together following the manual.
Ohmthis
Well-known member
Mayday, I'm not sure who and how many "pros" you have watched and or followed, but I think your numbers are skewed. If you are dealing with installer vs techs that maybe where the problem lies. Also the "pro" is only as good as the company they work for and the training that they receive from them. I agree it's not rocket science, but a month of research doesn't equal the time in the field to know a mistake or not. You either learn from your mistakes or you don't, but if this is your only chance to do it, it's hard to learn and know the difference. People want to do things themselves to save money and I totally understand as I'm the same way. That being said, to do this right you would need a bunch of tools that 95% of diyers don't have. I.E. Gauges, vacuum pump, micron gauge, brazing rod, a good meter to measure temps, an extra nitrogen regulator, tank of said nitrogen, and the list continues. If you buy even decent stuff you will be upwards of $1200. That's a high investment to save money. My advice is to pay someone to design it. Install duct work and equipment. Run vents, drains, linesets, and anything else needed. Pay someone in the know to braze the lines and commission the system (this will save you the up front money for extra tools and you will most likely keep your factory warranty). And the sit back and enjoy the system that you installed. Its kinda the best of both worlds
Here's some generic information for DIY work on HVAC.
http://www.hvac-for-beginners.com/air-conditioner-ratings.html
+1 on comments that proper DESIGN is critical. Sizing of the A/C and Furnace is number one screw-up made by shady "installer pro's" . . . . but often even more important is DUCT-WORK design.
Most every house layout makes it compromise in attempting to install proper duct size, flow, and distribution to all parts of house, that also MUST have properly designed RETURN AIR ductwork if system will operate most efficiently.
OP you've really got to tell us more than "2 Family Unit" that you are attempting to DIY the HVAC. Is it duplex ranch style with wide-open basement so you can do anything necessary for proper system?? Or it 2 story cobbled up rental that formerly was one big house?? HUGE differences is attempting to accomplish appropriate systems.
http://www.hvac-for-beginners.com/air-conditioner-ratings.html
+1 on comments that proper DESIGN is critical. Sizing of the A/C and Furnace is number one screw-up made by shady "installer pro's" . . . . but often even more important is DUCT-WORK design.
Most every house layout makes it compromise in attempting to install proper duct size, flow, and distribution to all parts of house, that also MUST have properly designed RETURN AIR ductwork if system will operate most efficiently.
OP you've really got to tell us more than "2 Family Unit" that you are attempting to DIY the HVAC. Is it duplex ranch style with wide-open basement so you can do anything necessary for proper system?? Or it 2 story cobbled up rental that formerly was one big house?? HUGE differences is attempting to accomplish appropriate systems.
Falcon67
Well-known member
I'd also add that you can buy all the equipment you need on line - air handlers, outdoor units, combined units, A coils, etc, etc. That's not a problem even though your local supply house may not sell it to you. Your next issue would be finding a pro to install it and most would just walk away. And to get a factory warranty, typically you'd have to have a licensed pro do the install and test. So the downside is that you don't get it done right, it doesn't work well and there's $4000 of equipment sitting there. The factory says you pay retail for any parts no warranty sorry and you end up having to hire a company to come re-do things as needed at $125 an hour.
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inphx
Well-known member
I have purchased from this site befor for central and splits and will buy again for a new build: www.acwholesalers.com , i se enow they have local installers with rates posted.
TEXACMAN
Well-known member
I would suggest not doing HVAC yourself , hire a professional. I have dealt with customers who have bought there own equipment and tried to install themselves , it will more than likely cost you more in the long run. As far as equipment look for a good warranty and try to stay with seer ratings in the middle instead of the highest , you will not get a good return for the money and the parts after warranty will be high. Hope this helps. 
bigdav160
Well-known member
I've installed several systems. Like mentioned above, it's not rocket science. Manual J, manual d- mostly common sense.
You didn't mention much about the houses. What type of heating system do they have now?
Perhaps mini splits would be the wisest choice.
You didn't mention much about the houses. What type of heating system do they have now?
Perhaps mini splits would be the wisest choice.
Any tips on finding a good HVAC company?
HVAC is reputation
find one that has thirty truck
been in business forty years
been in same location thirty years
these are people that been around, know the regulation, know the community. i would never do any business with somebody who works out of a truck, no office and been in business less than 15 years
its all reputation, you need someone that going be around 15 years from now for service work
HVAC is reputation
find one that has thirty truck
been in business forty years
been in same location thirty years
these are people that been around, know the regulation, know the community. i would never do any business with somebody who works out of a truck, no office and been in business less than 15 years
its all reputation, you need someone that going be around 15 years from now for service work
Diesel Dan
Well-known member
Isn't this the truth.
It took 4 service trucks, many hours and several "do-overs" during the install of a new H.E. furnace and central a/c for my dad. Just like any service it can be hard to find qualified people to do the work, even if they do it daily.
That is how I looked at it but I have automotive a/c experience and had the HVAC guy at work help spec out my material. Back in '06 I removed a fuel oil furnace and installed a H.E. furnace and central a/c into our 1940s house. Unit was Arcoaire, had to plump the house for LP, installed a concentric vent kit etc. Unit has worked flawless since.
I only wished I could find any real professionals in my area. From the small 2 guy outfit to the largest companies in town none of them could ever answer most questions directly, and it took a year and half and 13 service calls for the very large company my builder used (has used for 30 years) to find a leaking coil in my upstairs unit. The first 8 calls they just kept jambing more r22 in there and said it was fixed. I had to force a manger to come to my house to finally get somewhere.
When I started building an addition on the house, I called many companies and had a couple salesmen come give me quotes. None of them even knew what a manual j/d was when I asked, never heard of flow balancing, they just walked around and quickly said 'oh you just need a 2 ton and some duct runs, that will be $16,000'... No room measurements, no window counts, sun directions, accounting for the 12ft vaulted ceilings, the 2 story open loft area. Yeah, **** You, get out of my house.
It's not necessarily the price, it's the lack of knowledge and any real research or presentation when throwing around big numbers, and seeing how ****** most install crews do the homes in my area. Things like putting some nitrogen in and if it holds pressure for 2-3min it must be leak free, then don't use micron gauges pulling vac, they just hook it up and go talk on the phone for 15min or go to lunch then come back and filler'up and call it good. I see guys adding r410 with the jug upright instead of upside down as liquid like it should. I see them hooking up gauges all the time, but commonly don't seem them using a temp probe, referring to any charts, using a calculator for anything, measuring outdoor temperature, reading the manufacture specs, using a scale, etc..
When I was installing a couple mini-splits 5 years ago or so I called around for a startup, and I was talking to the service manager of one large company I mentioned 'these are r410, you guys familiar with these'? He replied, well we have one tech that is also a master electrician and he does all the 'high voltage' stuff. ?! He thought 410 was the voltage!
Not knocking the trade by any means, and absolutely not saying everyone should just DIY instead. As I know there are some GREAT HVAC techs on this site. But just because you guys are awesome doesn't mean it's so easy for us all over the country to find a competent tech/company to come do our work. The term 'hire a professional for this complicated work' sounds easy but it is very very difficult in some areas.
When I started building an addition on the house, I called many companies and had a couple salesmen come give me quotes. None of them even knew what a manual j/d was when I asked, never heard of flow balancing, they just walked around and quickly said 'oh you just need a 2 ton and some duct runs, that will be $16,000'... No room measurements, no window counts, sun directions, accounting for the 12ft vaulted ceilings, the 2 story open loft area. Yeah, **** You, get out of my house.
It's not necessarily the price, it's the lack of knowledge and any real research or presentation when throwing around big numbers, and seeing how ****** most install crews do the homes in my area. Things like putting some nitrogen in and if it holds pressure for 2-3min it must be leak free, then don't use micron gauges pulling vac, they just hook it up and go talk on the phone for 15min or go to lunch then come back and filler'up and call it good. I see guys adding r410 with the jug upright instead of upside down as liquid like it should. I see them hooking up gauges all the time, but commonly don't seem them using a temp probe, referring to any charts, using a calculator for anything, measuring outdoor temperature, reading the manufacture specs, using a scale, etc..
When I was installing a couple mini-splits 5 years ago or so I called around for a startup, and I was talking to the service manager of one large company I mentioned 'these are r410, you guys familiar with these'? He replied, well we have one tech that is also a master electrician and he does all the 'high voltage' stuff. ?! He thought 410 was the voltage!
Not knocking the trade by any means, and absolutely not saying everyone should just DIY instead. As I know there are some GREAT HVAC techs on this site. But just because you guys are awesome doesn't mean it's so easy for us all over the country to find a competent tech/company to come do our work. The term 'hire a professional for this complicated work' sounds easy but it is very very difficult in some areas.
Blue
Well-known member
Dunno if this will answer your question, but....
I've done a lot of renting over the years. Lots of 2 and 3 flats. And, most of the time, if the landlord has DIY'd the HVAC, they've screwed it up somehow. Either the AC is too big, or too small. Or the furnace is intermittent. There's just too many things to screw up.
honcho
Well-known member
HVAC-Talk is not Do-It-Yourself friendly. DIY and pricing information are forbidden topics.
Unfortunately, don't have a good single place to recommend. You can dig up most information but the HVAC industry, for many reasons, is not friendly to do-it-yourself people. There are good, honest HVAC people but they seem to be scarce in my area. We had a new high efficiency system installed about 2 years ago and while the small company we dealt with did a reasonably good job on the configuration and installation, I would have been happier to do it myself, even at the price we paid them.
Good luck