Isn't that "room temperature air" Why would the supply air be any different than the air that has already been conditioned? That's what's going into the supply, the conditioned air That's what I meant. Sorry I think I have it!
The air coming out of the vents should be 15 to 20 degrees cooler than the "room temp" air basically what's going into the intake Thus, in that scenario, the air temp coming out the the supply would be 57 to 62 degrees and be considered working properly.
So the air temp coming out of the supply actually changes with varying room temp, yet is still working properly, as long as it's 15 to 20 degrees difference. If it's MORE than 20 degrees that could indicate a problem as well One would think you would WANT the coolest air coming out Is your ducting in an attic?
A hot attic will lower the temperature spread. If so, check the spread at night after the attic has cooled. Mark is right about 20 degrees and more spread.. I just had a energy survey by my local power board and they checked the difference between the register and return temperature and found it to be 22 degrees.
They said that they wanted it to be around They said that the 20 to 22 degree difference indicated that my unit was not operting at peak. With this informtion as it was they went under my floor in the crawl space where my duct was and we found it to be cooler than my house was inside. He checked the duct and found several air leaks where the supply duct hooked onto the trunk.
He also found a place where a hole had been cut and patched and the patch had come off allowing a hole about 4 x 4 inches. He told me to go to HD or Lowes and get some duct sealing paste and oat over these air leaks I might add that after he left I found several more supply lines that were leaking and one had come loose from the trunk completely.
The only thing that puzzles me is the explaination of why the returns would read 64 when the temperate in the houe is Can someone explain this to me, please as a freind of mine is telling me that the air going back in returns should be the same at thetemperature in the house. You had all those leaks in your ducts and it actually made the temp spread larger How odd, but I have heard that you want no more of a temp split than 15 to 20 degrees.
Now I'm paranoid. I don't think there are any.. Reason being is that when I go into the attic it is extremely HOT I would think if there were leaks it would be cooling the attic as well To me, the air going into the return register should be about the same temp that the house currently is I mean it is sucking air from inside the house into the intake Since the air being sucked into the intake is coming from inside the house, wouldn't one think that the current temp in the house would be the temp of the air going into the intake?
I think it is. Even if the system is in the basement and the returns are not sealed well from the attic in the wall cavities the air can be pulled out of the attic. I had 78 degree air in the house and 85 degree air at the air handler. OK, I live in Texas. Current temp outside is Current temp inside my house is 86, even though I have the thermostat set at I had a new unit installed 5 years ago, but that never resolved this issue.
I have put radiant barrier in the attic and added 5" of insulation. Nothing, absolutely nothing is helping to get the temperature down in my house. I put a temp guage in the vent located in my dining room at it is reading 90 degrees.
I can go to other houses of the same size and their house is cool as can be. Can someone please give me some advice? I've been putting up with this for 15 years now and its never gotten any better, only worse. Have an energy audit performed on your home. From a long distance perspective, I can give you some advice and things to look at to help narrow the problem down.
Without being there, I can only guess at what the real problem is. I can give you, the homeowner, some things you can do. After that and, no improvement is attained, a trained person needs to take it further. There are a lot of factors which impact the ability of your unit to pull down the temperatures.
The energy audit with IR imaging should certainly be done if unit itself is sized and operating properly but is not pulling the temperatures down. You should expect a 15 to 20 degree temperature differential from the air temp going in and the air temp coming out, after the unit has been running a period of time.
I suggest you use 2 accurate thermometers. Put one into a return duct closest to the unit as possible. Put another into a supply duct as close to the unit as possible. Doing this right at the plenum is preferred. If you are getting a lot of condensed water leaving the unit, you can expect the temperature difference to be closer to the 15 degree differential range.
As the air in your home cools and the moisture is removed, you should get closer to the 20 degree differential range. If you have lots of windows and very large windows, you can expect the unit to have a more difficult time pulling down the temperatures. Windows facing the sun all day should certainly have blinds or curtains closed. Many times folks have many plants in front of windows and want the sun light to come in, in addition to keeping them well watered.
Also if your windows and doors do not seal when they are closed, you'll get some infiltration of hot humid air that will impact the effectiveness of the unit. Lots of people kids? If you do a lot of cooking and baking, that surely has an impact. All of the things I mentioned may not pertain to you but need to be mentioned so you can do your own audit before bringing in experts. The next issue may be duct leakage. Ideally, the cooling plant should be located in the center of the house.
This is not always the case. Units located at one end of the house, trying to condition several floors or just merely the length of the house can have issues also. This is evident when one end of the house or, upstairs rooms aren't as cool as desired. If the unit is too large for the house, you can expect problems also which negatively impact the comfort of your home. Duct sizing and air flow balances can be an issue too. So basically, I'm suggesting you do an audit yourself, looking for areas where the building might have problems.
That would include heat sources like home electronics, large CRT or projection tv's, etc. Also monitor if the unit has a tendency to cycle on and off a lot. Take a look at the temperature differential in the evening and at night too.
If it gives you the temperature differential or, close to it, you need to look at insulation and other infiltration problems. With all that said, I now look toward the unit itself. My first thought from the information you have provided and, if I discount any and all of the infiltration issues and, if your technicians have accurately determined the unit is indeed functioning with the proper refrigerant charge, etc.
That's not to say that is what it is, I would have to be there to accurately determine the problem, this is only an educated guess. I had a customer some years back complain their unit ran perfectly all day. Then it seemed from 5 o'clock on, the unit just stopped cooling like it should. When I went to look at the unit, after 5 o'clock, the family car was parked right in front of the unit, blocking air flow around the condensing unit.
That's where the husband parked the car every day when he came home from work. This proves that many times, a problem is very simple to resolve. Perhaps you should check your condensing unit to make sure it is not obstructed by plants, grass clippings, debris in the coils. If it is under a deck or low overhang, it could be recycling the hot condenser air, not cooling the refrigerant to the required temp.
Now if the refrigeration techs. But from the responsiveness you have expressed these guys have provided you, I'm inclined to think they want to do a good job and want you to be satisfied.
Keep calling them out until it has been proven nothing is wrong with the unit itself. They should be able to help you identify other causes, if there are any.
Have the same issue, I am not sure of the exact temp comming in or out, all I can say is is not cold enough.. I've been in places that the air is cold, my air is NOT. I have a 17 sq ft house and a 4 ton AC, the unit is only 4 years old and think it should at least cool down the place so it's comfortable, that's all I want..
I just had a new rooftop 14 seer Trane installed. Stuck a temp probe in the vent and my digital Fluke meter shows It's a 3 ton unit for my sq ft house. Seems to have no problem getting to 78 degrees but trying for 77 degrees digital honeywell thermostat takes a whole lot longer runtime.
Outside temp is currently here in Vegas. It replaced a 27 year old Whirlpool that although still cooled ok, was vibrating the whole house and the gas heater part of it was badly rusted and a carbon monoxide hazard, so it had to go. Then allow the AC unit to run at least 15 minutes. Place the thermometer on a vent and leave it in place for five minutes. Write down the temperature.
Move the thermometer to a return vent and do the same. The air coming out should be 14 to 20 degrees cooler than the air flowing in. Move the thermometer to a vent in each room or area of your home. If any of the vents are much colder or warmer than another, there may be a problem with the ductwork, or the distance may be too great from the blower.
Book Now. Supply vents : These are the vents that blow air into each room. The conditioned air goes from your air conditioner or furnace, travels through the ductwork and exits out the supply vents.
Return vents : What is a return vent? These vents suck the air from each room and send it back to the air conditioning or heating system. Return vents exist to remove the extra air. Obtain a temperature probe : This device will provide a quick and accurate measurement of the surrounding air temperature. Record supply vent temperatures : Go to three supply vents and measure their temperatures.
Determine the supply vent average temperature : Add the three recorded temperatures together and divide by three to get the average temperature of the supply vents. Determine Delta T : To figure out Delta T, subtract the temperature of the return air from the average temperature of the supply vents.
Replace the air filter : Doing so can often reduce the difference in temperature. Hire an expert: You can have a professional increase the speed of your blower motor, clean your coil and look for other potential issues with your system.
This measurement can be made with an inexpensive thermometer and a manifold pressure gauge set. Evaporator outlet temperature varies according to outside ambient air and humidity conditions.
Further variations can be found, depending on wether the system is controlled by a cycling clutch compressor or an evaporator temperature sensor.
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