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JLeslie's avatar

Would you ever have a 5 ton air handler inside and a 4 ton outside?

Asked by JLeslie (59822points) April 23rd, 2015 from iPhone

Would that combination cause there to be high humidity in the house?

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10 Answers

jca's avatar

I have a friend who’s an HVAC mechanic. I’ll ask him and answer tomorrow.

kritiper's avatar

A/C units dehumidify the air, so depending on how big your house is, no there shouldn’t be high humidity.

JLeslie's avatar

@knitper I know they dehumidify the air. If the unit is too big it can short cycle and it doesn’t run long enough to take the humidity out.

My air plan shows I’m supposed to have a 4 ton air conditioner. The unit inside my house is marked 4 ton hand written in permanent market, but the model is a 60, so it’s 5 ton. Outside it’s a 48. I was provided documents by my builder that the correct agency signed off on that combination. It doesn’t all match up.

What started my investigation is I’ve had to keep my air temp lower than usual so I bought a thermometer that measures temp and humidity and the humidity is high.

My builder has been horrible. The HVAC guy was here for something else and I mentioned the humidity (before I had climbed into the attic myself and looked at the model numbers) and his response was that my humidity is way too high and I can add a dehumudifier or a thermostat for humidity that overused the temp in the house and clicks on the unit. He can go take a flying leap. Sorry, but I’m so angry about my house build, about so many things, I am beside myself. I’m not going to be told that when I have lived in Florida most of my adult life in 6 different residences and this is the first time I’ve had a problem. They have done something wrong.

I’m going to call the agency that approved the HVAC systems, or maybe if I can figure out who does the calculations for the house to try and arm myself with information. The HVAC people are supposed to come back next week to look at it. They already have the information on the signed off paperwork.

I’m so frustrated.

@jca I really appreciate it.

jca's avatar

I spoke to my friend. He said the following (I wrote it down so it would be accurate):

For every 600 feet of house, the unit should be 1 ton. Both the inside and the inside have to be the same. The drive can be different but the evaporating coils have to be the same tonnage. The condenser coils have to be the same (compatible). Model numbers should show it to be the same. 48 = 4 ton. Each ton is 12 on the model number. 2 ton is 24. The air conditioner should take out the humidity. You shouldn’t need something separate to take out the humidity.

JLeslie's avatar

@jca Thanks. He confirmed what I thought. Very helpful.

Judi's avatar

It sucks that you’re going through this. :-(
Along with the building department I would contact the contractors licensing board.

kritiper's avatar

@JLeslie I see. But the larger unit wouldn’t add to the humidity problem (make it worse), hence my previous response.

JLeslie's avatar

@kritiper I think possibly it does if the unit is running less to reach the set temperature.

kritiper's avatar

@JLeslie Actually, it won’t. The added number of coils in a large unit will remove the same amount of humidity per time of unit operating to cool as a smaller unit. Larger units are more efficient, therefore need less time to do the same job, be it cooling or dehumidifying. Maybe adding a dehumidifier is what would be best for your system. Do you have a humidity gauge somewhere near the center of your house? Normal humidity for optimum comfort is 50 to 75%.

JLeslie's avatar

Interesting. If I had a 5 ton outside would it move the hot air out better and help the humidity?

I refuse to buy a humidity gauge or dehumidifier. I lived in incredibly humid southeast Florida most of my adult life and never needed one. I worked as a realtor in south FL and have many friends and relatives and no one needs a dehumidifier. The only time I have seen one was on very old house with a very old air conditioner on a listing I once had. I’m not going to pay for a dehumidifier nor am I going to pay to run my air conditioner more to keep the room comfortable.

I have been borderline in suing this builder for almost a year for so many issues. I have never had an experience like this. The incompetence has been incredible. This isn’t just some rant by a fed up women. I’m talking real incompetence.

This builder needs to give me the proper air conditioning unit, whatever it is, and set it up correctly. This is a brand new house, there is no excuse for a unit that does not keep the air temp and humidity at expected levels. I like the humid air, it’s past of why I live FL. It’s not like I expect my house to be very dry because I prefer it or am accustomed to it. The humidity is above expected limits. I have the full report from the people who do the calculations. I don’t know what to think. An HVAC person said you can have a 5 inside and a 4 inside and the 5 should make it more energy efficient. My boss, who is a GC, said he thinks my house should have a 2 and 5, 2 and 4 seems small to him. However, he also said he prefers to err on the side of putting in a unit a little small than too big. He isn’t an HVAC expert though, and he doesn’t claim to be.

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