On that 20 degree thing. After much YouTube. A guy explained. 20 degrees should be from the intake inside your home to vents coming out. So if your house inside is 82, the air coming out could be no more than 62.

As a rule of thumb. He said it is usually around 15 degrees.

So your unit is cooling now that you found the open duct?

Upstairs is much better. Got into 60s last night.
Air is coming out at 64 degrees upstairs.

Downstairs it’s coming out at 70. I think that’s the problem. Need to get some r22, possibly.

Knocking on wood and probably jinxing myself but My Lennox which came with my house (11 years old) is still getting it done. I have never had it serviced re; hose off, add refringent, etc. I'm afraid to now. I just know if I have someone come check it, for sure it will quit that night.

All I do is change the filter every month.

How do you know what size AC Unit you need? My next one, I want the Biggest possible then get the next one bigger. I like to hang meat in my house.

In this HOT weather, I keep thermostat on 68* it gets up to 72*-74* near my northwest facing windows in the afternoon. Sun hits them. I need solar screens added.

Be careful going too oversized. I have one 3.5 ton unit that serves just the master bed and bath. No clue why that was installed. It can definitely cool things down in a hurry, but because it doesn't run for long, it doesn't have a chance to really get the humidity out of the room. We run a dedicated de-humidifier in there constantly to keep it comfortable.

I don’t know how much the size matters. My father in law insisted on a 5 ton unit for his small house. The AC guy warned against it. It kicks on for 2 minutes, then is off for 5. lol

After all you YouTube, seems insulation is very important, windows too.

Saw several that drill 4 inch circles in drywall and fill in with blow in insulation.

The tonage that is required is determined by the square footage, windows, and insulation. Generally a manual J is done to determine if hat is needed when a building is built. However this can change over time if more insulation or window are changed. Going over in tonage is not good and generally will be worst for the area that it is cooling.

Once a unit is installed and charged it should not need refrigerant as the refrigerant is not a commodity like gas in your vehicle that is used and needs to be replaced. However like everything things happen and leaks are made due to rubbing, vibration, or brazes failing.

Echoing Lahota with a true story.
Guy insisted he wanted move up in size. I suggested solar screens, and some modifications to existing duct work. He refused to listen, you cant stick a 5 ton system on 3.5 duct sytem, etc.

2 years later, he ask me about cleaning mold from supply grills and finding solar screens because his bills were so high

If it looks dirty, it is filthy. Pull the disconnect by the unit, and back flush with a garden hose.

So what are some good solar screens?

Radiant shield was the first thing I installed in the attic of the Texas house. Instant 20 degree temp drop in the temperature of the attic door, ceilings and walls upstairs. The AC finally shut off. Home Depot/Lowes has small sheets for sale; get the sheets which roll out.

The man came today. Needed 9 pounds of Freon, between 2 units. 90/pound. 800 bucks.

Did he have a reason for the freon loss?

I think he said evaporator coil.

Damn when I had to get Freon back in May it was $45/lb.

Leak?

Do you have R22? I saw it for 60/pound on Craigslist

Closed systems should not require freon, must have a leak in system. Could be matter of time before system fails..

The price of refrigerant will vary from the type of refrigerant and from company to company. The price can be influenced from how the company bought the refrigerant by the pallet or by the drum, wether the company is small or large, how much they used on a job, or just what they want to charge.

The last I checked we are charging $60 lb for R22 and $35 lb for 410A.

The 9 lbs is a good amount used and I wold bet that the leaks are in the evaporator coils as well. The leaks will not get any better and will only get larger as time goes on. If you are planning to be out of the house in three years if you don’t replace them by then plan to give some money to the buyers to replace the units.

He did tell me 11k for replacement of the 5 ton. He said that the entire unit needed replacement. I said the gas heat in the attic was fine, he said it wouldn’t work with a non r22 AC unit They had to be compatible. And they don’t make R22 units anymore.

If I was gonna stay here, it would be a no brainer to get a quality system.

I will keep my eyes open for a good deal.

Yeah, went down a similar path maybe 10 years ago, refilled coolant 1-2 times and within 3 years or so the system was inoperable. You'll buy a couple of years refilling but likely about all.

I read the recommended run time to remove humidity is 15-20 minutes.

Not that simple. It also depends upon the specific target humidity and many other factors. But yes, a good amount of run time is required for latent extraction.

Marc

SEER. Standard energy efficiency rating. Pay they now or pay them later.

Exactly! My house cooled at 70* yesterday and compressor speed never went above 85% so there was more in it.