2 ton unit with a 2 ton air handler.
Equipment isn’t sized via square footage.
The range of discharge air temperatures suggest their might be a problem.

 

Thank you for the input.

Just for clarification: does "Equipment isn’t sized via square footage" mean that it is undersized, or that that the square footage is irrelevant?

I found an online calculator based on square footage, windows and people living in the house. Based on that calculator I should have a 3 ton system. When we throw in Florida weather, my 2 ton system seems to be on the weak end.

 

There is no such calculator that can size equipment based on square footage alone.
Sizing is done via manual J calculations.

www.loadcalc.net

A larger unit is never to be considered an upgrade. Bigger isn’t better.
Being in Florida, you need dehumidification. This is only accomplished via running the air conditioner.
What’s the humidity inside the home?

 

What color was the house before the new paint job? Did the unit work ok before?

 

You need someone to inspect the duct delivery system first. Seal it up and the unit will work better.

 

You need a good tech to check your system for refrigerant charge and air leaks.
Keep us posted.
Regards Teddy Bear

 

The humidity in my house is 58%. I measured it over night.

I did use another BTU calculator with more options for data. It suggested a 4 ton system for my conditions and house. Hence my current 2 ton system is indeed undersized.

I rented this house prior to buying it recently. I always had the AC on 75 F and it was able to keep up, but it was also running constantly in summer, at day time.

The house color was a very bright beige / yellow before it was painted dark red a week ago.

I guess the darker color pushes the unit to a max cooling temp of 78 F.

Well, something else happened. Last night I walked into a puddle of water in the garage. The condensation drainage was clogged and since I had the AC running on a lower temperature, it was running nonstop, producing more condensations, and it leaked into the air duct box below the air handler and through the wall.

I kept the air handler on fan only over night to help dry out the duct box.

Today I cleaned the drain pipe with vinegar, compressed air, hot water, a shop vac, a long cable binder, and Pipe Build-Up Remover.

Water flows now freely again, but while I had the handler open, I saw plenty of rust on the coils.

Based on your guy's experiences, will I need new coils or is this common on a 5 year old Carrier system?

How much are new coils in average?

Should I use this issue and get a 4 ton unit?

 

What other calculator did you use?
It will be very expensive to rip all the duct out and replace it for a 4 ton unit, will it not?

 

As has been mentioned, you really don't want a system that is any bigger than it needs to be. I intentionally have an undersized unit on my house.

Its sounds like your system has something wrong with it. I would find a good local contractor that you know you can trust and have them come evaluate the system. It might just need some duct work, or have a refrigerant leak that can be repaired.

If you do need a new system, who you hire to design and install it could make the difference between complete satisfaction and a holy nightmare. Take your time and choose a good company. It's Florida you are going to be working with them a lot over the course of your ownership of the house. Spending more initialy on someone who knows what they are doing will save you money in the long run.

keep us posted

 

I don’t think sizing is the issue.
A problem with the equipment and ducts probably are!

 

Thanks guys!

I made an appointment for tomorrow and let them check the duct work as well.

Why would I have to change all the duct work for a higher ton unit? Won't it just produce more cold air using the same duct work?

And I still need to know if those rusted coils are normal on a 5 year old system, and if that will cause issues any time soon.

 

No, you’d need larger duct to handle the 1,600 CFM required by the larger unit.
Surface rust on the tube sheet isn’t any cause for concern.

 

A 4-Ton unit pushes twice the air flow of a 2-ton, (CFM’s) the existing ducts will sound like a jet engine!

 

Rust is normal, all aluminum coils are and option on those units.

 

What county are you located? I have serviced a 2000 sq ft home with a 2 ton system. It was a surprise to me but I did a load calc and was very careful what parameters I entered. The home was built for energy savings. As been said, bigger is not better.

 

Manatee County.

If I want to upgrade, in case my current system can't be improved, how about a 3 ton system with existing duct work? The current system is completely silent, I wouldn't care about a little noise from a 3 ton system.

 

Stop obsessing over getting a bigger unit, it will cause a whole new set of problems for you.
See if your unit is running correctly first. Then go from there.
A larger tonnage unit should NEVER be considered any kind of an upgrade.

 

Duct is sized to handle a specific volume of air. You can't increase the system size with also changing the duct . Florida isn't well known for insulation. Perhaps the cheapest fix will be to have more insulation blown in.

 

_ _ -... 4-Ton A/C unit WILL DOUBLE YOUR PROBLEMS.

 

Why?

 

Do not change a unit out because of rust, its common and will really bad before it fails. Have the tech adjust the air flow to get the 30^F coil temperature drop verses the return air temperature to get proper dehumidification. You want <50%RH after a hour a/c run during the peak cooling.
In the end, you need a small whole house dehumidifier to maintain <%RH during typical green grass climate weather. I would also consider adding fresh air ventilation to get good indoor air quality and comfort.
If any of this appeals to you, check my past posts.
Keep us posted.
REgards Teddy Bear

 

Humidity is now at 48%.

I did a ton of reading and called a bunch of HVAC companies. There was not one post or person claiming that my 2 ton system is adequate, and several suggested a 3 to 4 ton system, considering all my circumstances.

AC is running nonstop and can't get below 78 F. In my home office its 84 F.

I'll wait for the appointment tomorrow but based on how this unit performed over the years with a much brighter exterior color, this thing doesn't cut it for me. I know people running their AC on 68 F all the time with no issues and I want that option as well, if I feel like it.

I'm already shopping around.

 

Standard design is to keep the house at 75 degrees inside when it's normal highs for your area outside. Be sure to tell the contractor that you may want to keep the house at 68 so they can size it to your wishes. Word of caution though, keep the house temperature above the outdoor dew point or you will have condensation and mold in the walls.

BTW make sure to tell them the office room is 6 hotter than the rest of the house so they can address the duct sizing for that room as they replace the rest of the duct to handle a larger system.

 

Your evap coil is probably dirty, and reducing air flow causing your poor cooling problem.

 

Tanks for the useful tip, I just found a few good YT videos and will get them cleaned.

 

I agree with rider. Stop obsessing with oversizing your unit.

Get a licensed contractor out there first to check everything out. Check the system in it’s entirety and the Duct work. If that all checks out, have them do a load calc on the house.
Make a list of issues your having across the house, with your ac, so you can tell the contractor in one visit.
Explain to the contractor that you would like to keep your house at 68. But please do keep in mind, living in Florida with the higher humidity, keeping your house that cold in summer will cause all of your windows to condensate. I see it all the time with these people from up north that want there houses at 68-70 in the summer. Then call to complain about higher electric bills, sweating windows, unit running all the time and never shutting off.

If your system is setup properly, to include tstat calibration, a house set at 75-76 is very comfortable in the summer here in south Florida.

 

68^F in FL will turn the walls/ceiling of your home into a mold farm. Cooling a home below outdoor dew point on long bases requires special construction that does not allow outdoor moisture into the cold inner layers of the wall and cealing.
Just like a cold can of beer sweating.
If you a/c is functioning properly, mainly the refrigerant and expansion device, and you can not get 78, you may benefit from a slightly larger condensing unit.
This room that is 84^F needs more cold air not necessarily a larger condenser.
Charge and function check first, it is a small house.
What was the temperature outside/outside, when the home was <50%RH?
Keep us posted. It is an interesting problem and feelings are strong for a good reason.
Regards Teddy Bear

 

That’s the sad part in our trade teddy bear. He will eventually find a Ac company that will install a 4ton system or whatever size he asks for just to get money. Then haul ass not return to deal with it and then have a reputable company to try and pick up the pieces.


Before the OP freaks out on me. I’m not saying you will do that. But I have seen it done SEVERAL times before.

 

You added more heat load to the house with the dark paint, paint it white.

You have a duct issue per your own admission that some rooms are not the same temperature as others and you can barely feel air in those rooms.

The system was built in 2014, it should be good for several years yet. Find someone that knows how to fix it.

 

X2

 

Well, the AC tech was here, here the summary:

- some returns just go into the living room instead to the AC collector box, not ideal
- there are no air flow adjusters at the distribution box
- he suggested a 3 ton system with some of the ductwork and the distribution box to be sized larger, and to adjust for the hot room


Meanwhile I heavily trimmed the bushes around the condenser unit outside, flattened some kinks in the ductwork in the attic, and gave the system a head-start over 2 nights by running it at 72 F.

I'm now able to run the system at 73 F, 74 F or 75 F throughout the day without the temp climbing higher later in the day.

I also think I wasn't giving it enough time to cool the walls etc down when the capacitor went out last week. It took 2 days to get a matching unit in the mail, hence the entire house must have been totally heat soaked.

While I won't be able to get much lower than 73 F on hot summer days, the last thing I need is condensation and mold. As a matter of facts 73 F feels pretty chilly when you walk into the house.

What you guys keep saying makes a lot of sense once I got over my ego. A system that runs clean at the designed temperature must be indeed better than over-sizing in an attempt to make up for other issues.

For now, the only remaining issue is the hot home office. That being said, it got much better in the recent days. My home office entails 4 large monitors, 2 computers, 1 server and a bunch of other electronics. They rarely run all at the same time, but this is definitely one reason for my issues. So I just bought a server rack and will move most of those heat sources out of the office and into the laundry room.

Another idea I have is an AC vent booster in, to help pull more cool air into the home office, since I can't regulate at the distribution box in the attic.

 

I just came across the site rules, and the part that disallows DIY topics.

I'll stay away from now on, because I will from now on do all work on my AC myself, even if I want to replace the entire system. Here are the reasons:

1.) The tech that showed up for a quote, well he didn't send it. Unreliable.

2.) When my capacitor went out some 2 weeks ago, I called another tech. He wanted $ to come out, and $ to replace the capacitor. That would have been $ bucks for a 5 minute job that I already diagnosed with a multi-meter, a 2 x 10 min ride, and a $ item. Business expenses aside, that's crazy. Not supporting this BS.

3.) About a year ago the fan in the airhandler locked up. A guy came out and replaced it under warranty. It took him a can of penetrating oil to force the shaft out. Meanwhile he soaked the entire fan housing. When he left and the fan came on, the entire house smelled like a chimerical plant. I had to pull the entire thing out, remove the motor, and clean it from the oil. That took me 3 hours all together because the fan spread the shit everywhere. Yet another BS job.

4.) I (also) have a background in IT. I long programmed forum software in the early 90s in Perl before this site (and most other forums) had been up and running. I literally contributed to the internet in itself. I hate to see that this once free medium now gets increasingly censored, capitalized and abused. Being able to find alternative solutions online is the main backbone of the world wide web. I do not support groups that want to limit my ability to repair, service or install products that I posses, in a house that I also posses.

I don't mind paying for services, do it all the time, when real quality is being provided. But in this day and age, you will usually be served with a half-assed job, a delayed job, or you will be scammed out of your money.

From now on I will invest every penny I save by doing the job myself, in quality tools that will allow me to do literally everything myself.

 

I just came across the site rules, and the part that disallows DIY topics.

I'll stay away from now on, because I will from now on do all work on my AC myself, even if I want to replace the entire system. Here are the reasons:

1.) The tech that showed up for a quote, well he didn't send it. Unreliable.

2.) When my capacitor went out some 2 weeks ago, I called another tech. He wanted $ to come out, and $ to replace the capacitor. That would have been $ bucks for a 5 minute job that I already diagnosed with a multi-meter, a 2 x 10 min ride, and a $ item. Business expenses aside, that's crazy. Not supporting this BS.

3.) About a year ago the fan in the airhandler locked up. A guy came out and replaced it under warranty. It took him a can of penetrating oil to force the shaft out. Meanwhile he soaked the entire fan housing. When he left and the fan came on, the entire house smelled like a chimerical plant. I had to pull the entire thing out, remove the motor, and clean it from the oil. That took me 3 hours all together because the fan spread the shit everywhere. Yet another BS job.

4.) I (also) have a background in IT. I long programmed forum software in the early 90s in Perl before this site (and most other forums) had been up and running. I literally contributed to the internet in itself. I hate to see that this once free medium now gets increasingly censored, capitalized and abused. Being able to find alternative solutions online is the main backbone of the world wide web. I do not support groups that want to limit my ability to repair, service or install products that I posses, in a house that I also posses.

I don't mind paying for services, do it all the time, when real quality is being provided. But in this day and age, you will usually be served with a half-assed job, a delayed job, or you will be scammed out of your money.

From now on I will invest every penny I save by doing the job myself, in quality tools that will allow me to do literally everything myself.

Last edited by beenthere; Today at 06:19 PM.

I am sorry to hear you have had such issues with this industry. It is a frustration I have had for years. It is also the same reason that I have had very few employees and work alone at this point. If they don't meet a certain level they ride with me, if they don't advance they are gone. I feel bad techs are the reason many homeowners don't trust this industry and you can't blame them. The problem is it is not just this industry. I have had issue with everything from A-Z including IT, I am fighting with an IT company right now. So does that mean I have to learn every vocation and do everything myself, or do I hire good people and hold their feet to the fire, if they refuse to preform to my standard then go to the next company till I find a good one and then support it fully which is the only way you will get rid of the undesirable in any industry.