DIY AC install?

[35mm]

We just purchased a new house that has two separate forced air furnaces. One feeds the original 1890 portion of the house and the other feeds the early 2000s addition.

The furnace the feeds the old part of the house heats and cools about 2000 sq feet. This unit is fairly new and works well.

The furnace that feeds the addition conditions just over 800 sq ft that is essentially one large room that has two story vaulted ceilings. This furnace is new and works well but it does not have ac installed. When the furnace was installed they made provisions to install an air conditioner but did not. Electricity for an ac has been run and there is a spacer between the furnace and the duct work where the ac would go.

I have access through work to get ac components at close to wholesale cost. I am a reasonably accomplished DIY guy. If I purchased and installed a condenser and the ac itself would a contractor be willing to make the gas connections and add the coolant? Or would no one be to touch it because it was installed by a homeowner?

Also, my zip code is 44903, how big of a unit should I get to cool a 18 foot tall 800 sq ft space?

 

[rlitman]

...If I purchased and installed a condenser and the ac itself would a contractor be willing to make the gas connections and add the coolant? Or would no one be to touch it because it was installed by a homeowner?...

I've found guys who will work with things I've installed, but it can be difficult at times.

 

[Trey T]

Since the system capacity requirement is unknown, it's absolutely not a DIY project. To determine the system requirement, the heat loading must be calculated/evaluated by a competent person. Generally, in a HVAC instrustry as a whole (commercial and residential), the system requirement is conducted by a licensed engineer (aka a competent person). Not to say that a technician (residential HVAC contractor) isn't competent to determine the system requirement, but the responsibility requirement is so high that it's absolutely not a DIY project.

If you buy a system and the contractor do not agree because there's a permit requirement that he has to meet, that system will render useless. Ultimately, if you want to go down your-so-called "DIY" approach, get your contractor in place first and also determine if a permit is required.

 

[rlitman]

...If you buy a system and the contractor do not agree because there's a permit requirement that he has to meet, that system will render useless. Ultimately, if you want to go down your-so-called "DIY" approach, get your contractor in place first and also determine if a permit is required.

+1000 Yes to all of this!

Don't go buying and installing parts without having your contractor on-board FIRST.

 

[bonneyman]

It's been my experience that finding someone to install a customers unit is not usually a problem - getting that guy to come back for warranty is! A break-down during the warranty period almost always devolves into a he said/she said with the equipment seller blaming the installer and the contractor blaming the failure on the equipment. (Leaving the customer in the lurch with no A/C). I've gotten many calls from folks in such a situation, wanting (and begging) me to come out and fix their problem - and then have me fight it out with the manufacturer for payment. Not an enviable position, I assure you.

If you are a competent mechanic and understand electrical and welding, you could install an older R-22 system and be fairly certain it will function adequately. (Not so with the newer R410a units). The biggest problem is getting someone whose licensed to handle refrigerant and willing to (basically) give away the profit of said license by evacuating and then properly charging the system.
It takes years of training and practice to get charging right, and the license doesn't come cheap, either. The reward for all that effort comes in making a profit when doing installs. When a contractor installs a customers unit, he doesn't make the mark-up he normally would, and most times customers don't want to pay extra for the "simple" evac and charge. But the contractor is still legally on the hook for warranty - even though he didn't install the equipment. It's why I (and most licensed contractors) won't install customer-bought equipment. Though things have changed and lots of guys ware willing to do almost anything to make a buck. But buyer beware!

 

[eddieK]

It's been my experience that finding someone to install a customers unit is not usually a problem - getting that guy to come back for warranty is! A break-down during the warranty period almost always devolves into a he said/she said with the equipment seller blaming the installer and the contractor blaming the failure on the equipment. (Leaving the customer in the lurch with no A/C). I've gotten many calls from folks in such a situation, wanting (and begging) me to come out and fix their problem - and then have me fight it out with the manufacturer for payment. Not an enviable position, I assure you.

If you are a competent mechanic and understand electrical and welding, you could install an older R-22 system and be fairly certain it will function adequately. (Not so with the newer R410a units). The biggest problem is getting someone whose licensed to handle refrigerant and willing to (basically) give away the profit of said license by evacuating and then properly charging the system.
It takes years of training and practice to get charging right, and the license doesn't come cheap, either. The reward for all that effort comes in making a profit when doing installs. When a contractor installs a customers unit, he doesn't make the mark-up he normally would, and most times customers don't want to pay extra for the "simple" evac and charge. But the contractor is still legally on the hook for warranty - even though he didn't install the equipment. It's why I (and most licensed contractors) won't install customer-bought equipment. Though things have changed and lots of guys ware willing to do almost anything to make a buck. But buyer beware!

If you do it yourself. You are 100% responsible for the warranty.

 

[35mm]

The biggest problem is getting someone whose licensed to handle refrigerant and willing to (basically) give away the profit of said license by evacuating and then properly charging the system.
It takes years of training and practice to get charging right, and the license doesn't come cheap, either. The reward for all that effort comes in making a profit when doing installs.

This is what I was worried about. Not looking to screw the guys who actually know what they are doing. I like to have projects and I am not opposed to saving some money, but I know there are times when jobs are best left to the pros. Looks like "let the pro do it" is the consensus.

What is the guesstimate on how big of an unit I would need is?

 

[yeldogt]

If everything is really ready to go -- there is not a huge amount of work if the condenser electric and placement are known and close to the inside unit.

i'm not sure you will save all that much .. why not get a couple estimates. You need a proper load done on the room and evaluate what works with the unit that's installed. I'm guessing here .. but they fact that someone did not want to install AC at the time leads me to believe that money may have been a concern and the furnace may have been a basic model that now 15 years old.

 

[eddieK]

This is what I was worried about. Not looking to screw the guys who actually know what they are doing. I like to have projects and I am not opposed to saving some money, but I know there are times when jobs are best left to the pros. Looks like "let the pro do it" is the consensus.

What is the guesstimate on how big of an unit I would need is?

It's not about "screwing someone"..It is about recognizing the value of certain expertise.

800 SF? Sounds like two tons depending on exposure, insulation, fenestration etc...

 

[bonneyman]

This is what I was worried about. Not looking to screw the guys who actually know what they are doing. I like to have projects and I am not opposed to saving some money, but I know there are times when jobs are best left to the pros. Looks like "let the pro do it" is the consensus.

What is the guesstimate on how big of an unit I would need is?

Yeah, it's hard to know nowadays who's good because so many companies push the "sell people a new unit" line. Techs are paid by commission (not hourly), so they tend to be salesmen (and not repair technicians). BBB and ads don't always help. Best bet on finding a good company is personal referral. Talk to your neighbors, friends, co-workers, and relatives - find out who they use.

 

[Bretny]

If your calling refrigerant "coolant" pay someone to do it.

 

[TractorJeff]

Coolant?
Refrigerant.....
Its all in the Translation but still basically the same meaning.

 

[Showkey]

We have hashed this DIY topic in prior posts. If warranty is the only concern ...... A DIY guy can buy three complete units for the price of one installed unit. So DIY guy uses the two extra units for parts if the need arises.

 

[6768rogues]

My brother bought his own unit and the condenser came with enough refrigerant for the system provided he used no longer lineset than was stated. He hooked it up and it works fine, in a part of FL where AC failure it not something he wants.

 

[Falcon67]

My experience has been - knowing more that a few contractors - is that a small system install can be very much a decent DIY project. However, you will likely be the service tech forever unless you already have a good relationship with a AC person/company doing other work for you. Also, check the warranty. There are a lot of warranties that will not be honored unless the system is installed and certified by a licensed installer that sells the brand. Again, who you know can be an end run in some cases.

 

[AA7483]

I rarely ever install a unit without having to adjust the charge even if the lineset is less than stated. Who is going to do the load calculation? Ensure the duct sizing is correct? Static pressure testing to set the fan speed? Do you have a manometer to set the gas pressure? A combustion analyzer to make sure your furnaces are firing safely? The system needs to be properly brazed in evacuated and commissioned. And when the system fails due to being installed improperly who will honor the warranty? There is so much that goes into a properly installed system. I hate to see you throw your money away. I would suggest hiring a professional.