Air Condition Feezing Up.

[Parmesh P.]

Last summer, I spend more than 1.7K on AC repairs ( adding refrigerant gas, cleaning coil and ducts, and much more) that seems to go nowhere. The AC for my second floor STR is not able to cool the unit during the hot weather. This unit has 2200sf with five bedroom and five bathroom. The AC unit and air handler are both 3ton and are 7 years old. I had three independent thorough assessment of the entire system and all three companies said the system is in great health and is working as it should. On further questioning I was refer to the top guy of two of these companies who said ALL COOLING UNITS are designed by manufacturer to keep the interior 20 degrees lower that the temperature outside and the thermostat should be set to reflect that. Most of what I am reading seems to support the 20 degrees split differential. However, to me, this seem to make no sense when considering temperatures of 115 degrees in central florida occurs very often. This "freezing up" problem seems to be widesread in centaral Florida. I am thinking of using a 5ton airhanler and heat pump to solve this problem.

My question is, did anyone ever had this issue? How did you solved it while maintaing and indoor temperature of 73 degrees in the hot weather?

[Michael Baum]

Ok @Parmesh P., 115 degrees is not common in Orlando FL. It has never been that hot there in recorded history. 103 degrees was the hottest recorded in 1921.

I am not trying to say it isn't hot, but numbers have to be accurate in order to figure out the problem. The average high in Orlando is 92 degrees in July. An increase of 15+ degrees in delta is a pretty big jump.

The very basic calculators I tested show you need about double the number of tons to fix this. Most of the ones I tried for Zone 1 calculations say 6-6.5 tons. One said at least 4.

I didn't do the math for the delta you are looking for but if you want it 72 degrees inside and it is 95 out there, that is only 23 degrees so it should be doable, if you have enough cooling.

There is so much more that goes into this. Duct size for both main and return play a role.

You might need to add a few mini splits upstairs in order to normalize things. That might be the best way to fix this without going over.

There are several DIY mini split systems you can install for much less than a pro install.