Trouble with upstairs air conditioner?

[Coug]

Has anyone with a second floor been having trouble cooling off the upper level with the higher temperatures this week?

I'm trying to figure out if I should be calling the HVAC guys or if it's just hot and I'm getting what I'm going to be getting.

 

[Iam4utalways]

Has anyone with a second floor been having trouble cooling off the upper level with the higher temperatures this week?

I'm trying to figure out if I should be calling the HVAC guys or if it's just hot and I'm getting what I'm going to be getting.

Yes. We ended up getting a small window unit to supplement. Have even had to run the window unit in the winter to keep the upstairs from getting too hot. The house has vaulted ceilings in living room and dinning area. Great for hanging Vol art, horrible for heating and cooling.

 

[volinbham]

sleep on the couch

 

[GAVol]

Has anyone with a second floor been having trouble cooling off the upper level with the higher temperatures this week?

I'm trying to figure out if I should be calling the HVAC guys or if it's just hot and I'm getting what I'm going to be getting.

I've had it explained like this. Unless you've overbought as far as the tonnage on your AC unit, an upstairs unit is good for about 18-20 degrees of improvement over the outside temperature. Once you get into the mid 90s, you're going to feel a little difference.

 

[Jxn Vol]

It may be low on coolant. 1 of my 3 units has a small leak. I have my HVAC guy come out and service them every spring. Probably $100-$125 will get it serviced and any problems diagnosed.

 

[Coug]

I've had it explained like this. Unless you've overbought as far as the tonnage on your AC unit, an upstairs unit is good for about 18-20 degrees of improvement over the outside temperature. Once you get into the mid 90s, you're going to feel a little difference.

I've heard the exact same thing. We keep it at 69 and it got to 74 today upstairs. 71 or 72 I could feasibly understand. Not sure about the 74 though.

It may be low on coolant. 1 of my 3 units has a small leak. I have my HVAC guy come out and service them every spring. Probably $100-$125 will get it serviced and any problems diagnosed.

It's pretty much a brand new unit. We just had it put in last year. I might give them a call anyway and have them come check it. It'll be free I can tell you that much.

 

[VolsSportsFan]

I've had it explained like this. Unless you've overbought as far as the tonnage on your AC unit, an upstairs unit is good for about 18-20 degrees of improvement over the outside temperature. Once you get into the mid 90s, you're going to feel a little difference.

Yep. A few years ago when we had that scorching hot week in June, where the heat index got up over 110, our upstairs main room was at about 85. We merely avoided that room for the most part except in the mornings and later in the evening.

 

[Orangedogsrule]

If it's a new unit, did you get the thicker 4" air filter installed? My new unit's filter is supposedly good for six months. However, because the return air register is by the stairs, more dust is kept airborne and it needed replacing. Reduced flow and all that.

However, we found out though that the other, and major, culprit was a pinhole in the new airhandler coil. Service tech said they aren't common, but do happen.

As an aside, we had had the TVA Energyrite survey done. Followed all their recommendations. One unit for both floors with a special made, dampered plenum to split supply up and down. It made the whole house cozy in winter, easy to cool in summer, and cut our bill significantly. The super insulation in attic and walls and I can almost heat the whole house in fall with a candle.

 

[Coug]

If it's a new unit, did you get the thicker 4" air filter installed? My new unit's filter is supposedly good for six months. However, because the return air register is by the stairs, more dust is kept airborne and it needed replacing. Reduced flow and all that.

However, we found out though that the other, and major, culprit was a pinhole in the new airhandler coil. Service tech said they aren't common, but do happen.

As an aside, we had had the TVA Energyrite survey done. Followed all their recommendations. One unit for both floors with a special made, dampered plenum to split supply up and down. It made the whole house cozy in winter, easy to cool in summer, and cut our bill significantly. The super insulation in attic and walls and I can almost heat the whole house in fall with a candle.

The unit has the internal accordion style filter in it that you have to crawl up into the attic and change. Until this most recent heat wave I had been running a regular return filter in the ceiling in addition to the internal filter. I took out the ceiling filter thinking maybe it was impeding the unit, it turns out that wasn't a problem. The attic could probably greatly benefit from additional blow in insulation as well as a radiant foil barrier to be quite honest.

 

[Roustabout]

I was going to ask you about insulation and duct work.

 

[InVOLuntary]

What is your fan setting, "Auto" or "On"? I've found that having the fan run continuously helps. I run both my upper and lower units on the "ON" setting.

 

[Roustabout]

What is your fan setting, "Auto" or "On"? I've found that having the fan run continuously helps. I run both my upper and lower units on the "ON" setting.

don't do this. if you have to continuously run the fan there is an issue.

 

[Coug]

What is your fan setting, "Auto" or "On"? I've found that having the fan run continuously helps. I run both my upper and lower units on the "ON" setting.

We've always kept the system on auto. I've only heard of setting the fan to "on" if the system freezes over and you only do that for up to 4 hours to allow complete thawing.

 

[Rockvegas]

Work with an engineer that has his own HVAC business and talked about your question. Three common problems found with upstairs ac units are the tonage size of ac unit, small leak, and the most common is poor installation of ducts.

 

[InVOLuntary]

We've always kept the system on auto. I've only heard of setting the fan to "on" if the system freezes over and you only do that for up to 4 hours to allow complete thawing.

I run mine continually, not so much because I've have issues cooling upstairs but for circulation and to remove allergens in the air. I don't understand why that would be an issue mentioned by another poster. I'm not a certified HVAC technician but I do my own maintenance and have installed several systems and have many friends in the trade. Never have I been told that was a bad thing to do.

Also, if your system is freezing up, that's an indicator that your system may be low on freon. Is your system an R22 or R410A?

 

[LouderVol]

OP do you have two units? One for both floors?

If you have just one do you have zone dampers? if its one you may need to re-balance it. it may be supplying 60 degree air for the lower floor as that is all it needs, but that same 60 degree air doesn't cut it for the hot upper floor.

If you have two, a problem with one in the attic is that it is cooling air that is hot as ballz. a lot of stress on the system, maybe even worse than direct sun, because at least you get some more airflow. as others have pointed out get a service guy out there, then next would be to insulate the ductwork in the attic. this can make a huge difference.

 

[BenGrimm]

Same problem. Just bought a new house that has 2 units. The last few days the upstairs has been hard to get below 77 by 3-4pm until a few hours after sunset.

I've been running the ceiling fans full throttle all day trying keep the air circulating. That seems to help a little.

 

[Roustabout]

I run mine continually, not so much because I've have issues cooling upstairs but for circulation and to remove allergens in the air. I don't understand why that would be an issue mentioned by another poster. I'm not a certified HVAC technician but I do my own maintenance and have installed several systems and have many friends in the trade. Never have I been told that was a bad thing to do.

Also, if your system is freezing up, that's an indicator that your system may be low on freon. Is your system an R22 or R410A?

It's simple. if you HAVE to run your AC continuously to cool (which was your recommendation. Not for allergens) then you are over working your system. Over working your system runs up your bill and could lead to early failure.

The bottom line is if you have to run it all the time to cool the house then you are not addressing the problem, which could be inadequate tonnage or insulation, or defective duct work.

If you have a tech who recommends running your AC like this without knowing those factors then they are incompetent.

 

[Coug]

Work with an engineer that has his own HVAC business and talked about your question. Three common problems found with upstairs ac units are the tonage size of ac unit, small leak, and the most common is poor installation of ducts.

The tonage was recalculated by the HVAC guys and I'm pretty sure this newer unit is a slightly larger than our old one. They also informed us that we originally didn't have enough vents for the size of the unit we had and installed two more vents to the upstairs floor. There are in fact several ducts in the rooms upstairs that don't seem to be blowing quite as hard as others. The air ducting for those rooms are original since the house was built back in '93. To my knowledge they haven't been replaced or upgraded since then.

Also, if your system is freezing up, that's an indicator that your system may be low on freon. Is your system an R22 or R410A?

Just had the unit replaced last year so I assume it's the newer of the two coolants. I honestly am not sure.

OP do you have two units? One for both floors?

If you have two, a problem with one in the attic is that it is cooling air that is hot as ballz. a lot of stress on the system, maybe even worse than direct sun, because at least you get some more airflow. as others have pointed out get a service guy out there, then next would be to insulate the ductwork in the attic. this can make a huge difference.

Yes, we have two units. One for the basement and main floor and one for the upper floor. I'm completely with you on the ductwork. Probably have to spend some money and have someone do some ductwork upgrades honestly.

Another thing I read online is if you can go up into your attic and see the crossbeams sticking up above the blown-in insulation then the old insulation has settled over time and you should have more blown-in insulation put down.

 

[InVOLuntary]

It's simple. if you HAVE to run your AC continuously to cool (which was your recommendation. Not for allergens) then you are over working your system. Over working your system runs up your bill and could lead to early failure.

The bottom line is if you have to run it all the time to cool the house then you are not addressing the problem, which could be inadequate tonnage or insulation, or defective duct work.

If you have a tech who recommends running your AC like this without knowing those factors then they are incompetent.

I've been working on AC systems for over 20 years. I perfectly understand the workings of an ac. If the unit is undersized there really is nothing he can do to the unit other than try to help it. If the unit is running all the time it really doesn't matter what position the fan switch is on now does it? If it is cycling and the fan is running continuously it can extend the time between cycles so I'm not sure how that's taxing the system. There is zero reasons not to run the fan continually except for the little bit of extra power consumption that the fan uses. You might say that the decreased life of the fan motor but there are studies that show there is less stress on the fan keeping it running than constantly starting and stopping. So you go ahead keeping on keeping on and I'll do the same. :hi:

 

[InVOLuntary]

The tonage was recalculated by the HVAC guys and I'm pretty sure this newer unit is a slightly larger than our old one. They also informed us that we originally didn't have enough vents for the size of the unit we had and installed two more vents to the upstairs floor. There are in fact several ducts in the rooms upstairs that don't seem to be blowing quite as hard as others. The air ducting for those rooms are original since the house was built back in '93. To my knowledge they haven't been replaced or upgraded since then.



Just had the unit replaced last year so I assume it's the newer of the two coolants. I honestly am not sure.



Yes, we have two units. One for the basement and main floor and one for the upper floor. I'm completely with you on the ductwork. Probably have to spend some money and have someone do some ductwork upgrades honestly.

Another thing I read online is if you can go up into your attic and see the crossbeams sticking up above the blown-in insulation then the old insulation has settled over time and you should have more blown-in insulation put down.

Have you noticed whether the unit is freezing up? If it's freezing up that's a decent sign that it's low on freon. If it is that new I would bet it's a 410 system. The only scenario I could see where they would have went back with the 22 is if they only replaced one of the two components such as the outside unit or the A-Coil inside. If you change the gas you must change all the components and thoroughly flush the lines. The two gases have totaly incompatible oils that when combined form an acid that can eat the unit up from the inside.

Another mistake I've seen happen with these new 410 systems are they were charged incorrectly. The 410 is a blended gas and must be charged in the liquid state. Otherwise you get a disproportionate blend of the gasses and the unit will not run in top efficiency.

As to your attic, more insulation would not be a bad thing. Most ceiling joist are 2x4 so if you're seeing joist you are severely lacking in insulation. I would have at least 10" of insulation. Also, I've found most attics are not ventilated nearly enough. When I first built my house I suspected as such and I installed power, thermostatically controlled gable vents. We were experiencing similar issues as you were.

 

[Coug]

We had gable vents and a thermostatically controlled fan in the roof previously. The fan was removed when the roof was reshingled and was replaced with ridge-line vents. The gable vents are still there.

 

[InVOLuntary]

We had gable vents and a thermostatically controlled fan in the roof previously. The fan was removed when the roof was reshingled and was replaced with ridge-line vents. The gable vents are still there.

My roof had/has the ridge vents too but it still was getting very hot in the attic. Have you checked the temp up there? I would reinstall those fans. They are relatively cheap and reducing that attic temperature will definitely help the cooling.

 

[Coug]

My roof had/has the ridge vents too but it still was getting very hot in the attic. Have you checked the temp up there? I would reinstall those fans. They are relatively cheap and reducing that attic temperature will definitely help the cooling.

So I had Chancey & Reynolds come by today to check the unit since they are the ones that put it in. You'll never guess what the diagnosis was... everything checked out just fine! The coolant level was where it should be so there were no leaks or signs of freezing. Pretty much just got the "20 degree difference" line again. My own thoughts are confirmed, it isn't an HVAC problem it's an energy/insulation problem.

 

[InVOLuntary]

So I had Chancey & Reynolds come by today to check the unit since they are the ones that put it in. You'll never guess what the diagnosis was... everything checked out just fine! The coolant level was where it should be so there were no leaks or signs of freezing. Pretty much just got the "20 degree difference" line again. My own thoughts are confirmed, it isn't an HVAC problem it's an energy/insulation problem.

That's what I guessed. Did you mention earlier that you could see the tops of your ceiling joist in your attic?

Also, do you raise the temperature setting on your thermostat when you are away and then cut it back down when you arrive back home?

Another thing you can do to get you through the tough times is make sure you totally block as much light from the windows. You won't believe the difference it makes.

Another trick I've done is set a gentle spray of water on your outside condensing coils. It will cost you a little in the water department but it will help the AC cool better.

And, I would definitely run my fan constantly, both up and down. It will help mix the air and pull a little of the cool air from down stairs up to assist the upstairs unit.

Long term solution is to figure out where the heat is coming from. My guess is you have a huge heat load in the attic. Venting it better and more insulation should help with that. Keep me/us informed on how you get it solved.