Weird question about central air

[Superfly]

All interesting things to note. Thrilla - you are in Vegas. Does it make a difference that your humidity is much lower compared to mine? My humidity usually runs 90%. I will say that, last Sunday when the AC was frozen and inoperable, it wasn't as terrible as I thought it would be, just because we had fans going. But dammit, if I'm going to pay $400 a month, I should be able to be so cold, MY toes freeze off at night.

The fan that is on the unit itself seems to run all the time - whether it's on AUTO or ON.

Thanks for the tips, too, Auntie. I may call Georgia Power and see if they can send someone out here. They've done audits, but that's not helping.

Thanks for your info too, Tech. You and Porchev definitely understand this Georgia heat. :lol:

Porchev - thanks. I need to remember to call the AC company which installed the unit to see what size the unit is, and what the SEER rating is. All I know is it's a brand new system (or supposed to be).

 

[ksu_aviator]

OK I have a weird question. I try to keep my thermostat set on 75. Our electric bill is really high (around $400+ a month, during the summer) so I tried to keep it on 78 but it was just too hot, and my husband has COPD and emphysema, so he can't breathe when he gets too hot. Anyway. So during the hottest part of the day, when it's around 90 to 95 outside, the house is quite comfortable at 75. However, at night, when the temps drop to 70 to 75, the house is just awful. It's so hot. Last night, I went to bed about 3am, and my tee shirt was stuck to my back from all the sweat. Now does that make sense to you?

I'd think, logically, that it'd be hotter in the house during the day than during the night, but the night is often unbearable. Also, logic would dictate that 75 is 75, no matter what the temp is outside.

Also, let me reiterate - I run an extremely high electric bill. It's at least double, if not triple, of everyone else's here in the neighborhood. Now this is a brand new house, only about a year old. Last Sunday, we woke up and the house was really hot. We went outside to see if the unit was running, and it was, but along all the wires leading into the house, they were frozen solid. We turned off the AC and turned the unit strictly on fan, and left it on until the ice melted. Once the ice melted, the air started working again. We had the HVAC guy come out and he had to put in a couple of pounds of Freon and said he thinks we have a bad *something-or-other* part.

Would that have anything to do with us sweltering at night? Would it have anything to do with our electric bill being so much higher than everyone elses? I don't want to depend on this guy to tell me the truth, because of course he's going to say that everything's fine and I'm worried over nothing. My husband and my daughters both said that it's unbearably hot at night, but I don't dare turn the thermostat down below 75. I couldn't imagine what the bill would be.

Ours did that. I don't remember what the part was, but it had a valve and the valve wasn't open all the way. After he opened it the house has been great. If I were you, I'd call the manufacturer and get it repaired/replaced ASAP. They usually have a full parts and labor warranty for 2 to 5 years. Mine has a parts warranty out to 10 years. However, if your evaporator coil is freezing, check your return filter. If it is dirty, your ac can't get the air it needs. Also, be sure to use a hose and spray down your outside unit to get all the dust and dirt off it.

So, as far as the night thing goes; if the house temp is 75 and the outside temp is 70, you won't get the a/c to turn on so you'll have the same humidity inside as you do outside and it will be less comfortable than the dry 75 you had during the day.

If you want to cut down on your bills, get some solar screens. They made about 13% difference in our usage. Plus, it made 78 feel like 72 inside.

 

[Superfly]

Thanks. 2 questions. First, which is the return filter? Is that the one on the inside? We change that one every 30 days.

Secondly, what is a solar screen?

 

[Aunt Spiker]

Thanks. 2 questions. First, which is the return filter? Is that the one on the inside? We change that one every 30 days.

Secondly, what is a solar screen?

Yes - the return filter is the big one inside. That sucks in all the air which is cooled and then sent back into the house. In my house - the return duct is too small. Though it's 18" wide - it's too small for the size of the AC unit outside. Which means that it doesn't suck in enough air to then pump evenly into the whole house. Before our compressor went years ago, only 1/2 of the house was adequately cooled and our bill was ridiculous.

In fact - we had these problems before the AC died:

1) Return duct was too small - inadequate airflow through the unit.
2) There were no flanges on the AC ducts (what are these? the flanges - also called dampers - are flat pieces of metal installed at the beginning of each AC branch. The AC sucks in air through the return duct, cools it, then pumps it into the main AC line. There are branches coming off the large main AC line to each of the vents - each branch should have a flange/damper so you can adjust *how much* air gets through.)
3) There were large sections that didn't have insulation - some animal got under there and made some cozy homes for babies. Yuck.
4) Thermostat was inadequate - it was one of the old mercury types, so it was inaccurate.
5) And last but not least - apparently our unit was 'homemade' - someone bought it, and installed it unprofessional. It was the wrong size unit for the house. Your AC needs to be picked based on cooling square footage and other factors like 1 story or 2 stories as well as cooling-zone in the US (high humidity needs to be able to draw out more water from the air, etc)

Our big mistake - was not realizing any of this UNTIL we started to have problems. By the time we had all these problems figured out and fixed, it was too late - once the summer heat came after all the repairs were done the compressor had enough and kicked the bucket. (it froze over all the time) - that just sucks and is costly to replace.

Sure, we would have continued to have high bills even if the AC didn't go - the only way to fix that would have been to have a better unit that was more efficient (cooling amount and otherwise) installed.

This might not be all of your deal - but it's food for thought. ACs are complicated.

Right now: we use window units - it took me 2 years to accept that we had to use them. When one goes bad we just replace the individual unit for $150.00.

 

[longview]

The freezing up could be caused by low air flow, but something sounds like it is wrong.
A separate, but related issue may be your electric rate, my bill dropped a lot when
I moved from .13 per KWH to .098.
For your area, it would be a good idea to have a small AC, (window or portable)
as part of your hurricane kit.
My own AC broke last weekend, and it took me two days to get the part, (starter cap),
but my hurricane kit AC's kept the parts of the house OK for the time the big unit was offline.

 

[ksu_aviator]

Thanks. 2 questions. First, which is the return filter? Is that the one on the inside? We change that one every 30 days.

Yes. So that's not the problem.

Secondly, what is a solar screen?

It is a type of window screen that blocks the UVA from entering. That keeps the heat out. Ours came out to $35 a window and you'd easily recoop that in one summer.

 

[Superfly]

Thanks, Auntie. We aren't allowed :roll: to have window units. Although our HOA is crap right now so I could get away with murder and dare anyone to say anything to me about it.

longview - I don't understand why a window unit would work as a "hurricane" unit. *confused*

KSU - We have double-paned windows and they are tinted almost like a green color to make them energy efficient. Is that what you are talking about?

 

[longview]

Thanks, Auntie. We aren't allowed :roll: to have window units. Although our HOA is crap right now so I could get away with murder and dare anyone to say anything to me about it.

longview - I don't understand why a window unit would work as a "hurricane" unit. *confused*

KSU - We have double-paned windows and they are tinted almost like a green color to make them energy efficient. Is that what you are talking about?

Sorry, my Hurricane kit includes a generator that can run 2 small window units, fridge, freezer, and TV.
I can move things around and also run a microwave.
That with my food supply and fuel from the cars will let me "camp out" at home till the power is back on.
(this was up to two weeks for some after IKE)
Anyway I have now used my kit window units 5 different times, as friends and family needed them.

 

[Oftencold]

OK I have a weird question. I try to keep my thermostat set on 75. Our electric bill is really high (around $400+ a month, during the summer) so I tried to keep it on 78 but it was just too hot, and my husband has COPD and emphysema, so he can't breathe when he gets too hot. Anyway. So during the hottest part of the day, when it's around 90 to 95 outside, the house is quite comfortable at 75. However, at night, when the temps drop to 70 to 75, the house is just awful. It's so hot. Last night, I went to bed about 3am, and my tee shirt was stuck to my back from all the sweat. Now does that make sense to you?

I'd think, logically, that it'd be hotter in the house during the day than during the night, but the night is often unbearable. Also, logic would dictate that 75 is 75, no matter what the temp is outside.

Also, let me reiterate - I run an extremely high electric bill. It's at least double, if not triple, of everyone else's here in the neighborhood. Now this is a brand new house, only about a year old. Last Sunday, we woke up and the house was really hot. We went outside to see if the unit was running, and it was, but along all the wires leading into the house, they were frozen solid. We turned off the AC and turned the unit strictly on fan, and left it on until the ice melted. Once the ice melted, the air started working again. We had the HVAC guy come out and he had to put in a couple of pounds of Freon and said he thinks we have a bad *something-or-other* part.

Would that have anything to do with us sweltering at night? Would it have anything to do with our electric bill being so much higher than everyone elses? I don't want to depend on this guy to tell me the truth, because of course he's going to say that everything's fine and I'm worried over nothing. My husband and my daughters both said that it's unbearably hot at night, but I don't dare turn the thermostat down below 75. I couldn't imagine what the bill would be.

My first thought is that you're problem may be more with high humidity that with what sounds to this Floridian-until_I-Was-39 like rather moderate warmth. Is the air typically damp in the summer where you live?

 

[Superfly]

Sorry, my Hurricane kit includes a generator that can run 2 small window units, fridge, freezer, and TV.
I can move things around and also run a microwave.
That with my food supply and fuel from the cars will let me "camp out" at home till the power is back on.
(this was up to two weeks for some after IKE)
Anyway I have now used my kit window units 5 different times, as friends and family needed them.

Oh, gotcha! Thanks! (you're way better prepared than me)

 

[Superfly]

My first thought is that you're problem may be more with high humidity that with what sounds to this Floridian-until_I-Was-39 like rather moderate warmth. Is the air typically damp in the summer where you live?

Man, yeah. You walk outside and you feel like you walk into a wall of water.

 

[Thrilla]

All interesting things to note. Thrilla - you are in Vegas. Does it make a difference that your humidity is much lower compared to mine? My humidity usually runs 90%. I will say that, last Sunday when the AC was frozen and inoperable, it wasn't as terrible as I thought it would be, just because we had fans going. But dammit, if I'm going to pay $400 a month, I should be able to be so cold, MY toes freeze off at night.

The fan that is on the unit itself seems to run all the time - whether it's on AUTO or ON.

Thanks for the tips, too, Auntie. I may call Georgia Power and see if they can send someone out here. They've done audits, but that's not helping.

Thanks for your info too, Tech. You and Porchev definitely understand this Georgia heat. :lol:

Porchev - thanks. I need to remember to call the AC company which installed the unit to see what size the unit is, and what the SEER rating is. All I know is it's a brand new system (or supposed to be).

I'm in Texas now..the Hill country north of Austin ( bought a ranch here couple years back)
but yeah, humidity plays a big part... in fact, in Vegas, lots of folks use swamp coolers ( which adds humidity to the indoor air)... AC works far better in higher humidity, swamp coolers work better in low humidity,

 

[Oftencold]

Man, yeah. You walk outside and you feel like you walk into a wall of water.

OK. If you're home is of fairly modern origin, that is reasonably weather tight, let me strongly suggest a large dehumidifier, better yet two or more. I think that you'll find the results to be dramatic. Just remember to increase the frequency with which you water the houseplants!

 

[tech30528]

So what's the verdict? What did the AC tech find?

 

[Superfly]

So what's the verdict? What did the AC tech find?

Well he was here last year and didn't find anything but I called the AC company that installed my unit and did find out that I have a system called AirFlow, which is made by Lennox. It's a 3 ton unit, and has a SEER rating of 13.

 

[Porchev]

Well he was here last year and didn't find anything but I called the AC company that installed my unit and did find out that I have a system called AirFlow, which is made by Lennox. It's a 3 ton unit, and has a SEER rating of 13.

Based on your electric bill compared to people around you, I would still make sure that thing is working correctly. I read that SEER 13 is the minimum standard nowadays. Here is some more info that may help: Central Air Conditioning | Department of Energy

 

[Superfly]

Thanks, Porchev. We are waiting on the coil to come in. Once that comes in, we'll see what kind of difference (if anything) there is. *crossing my fingers* Also we called an independent electrician and he's going to be here on Monday to go through our house with a fine-toothed comb, to see if we can figure out what's going on.

 

[Baralis]

OK I have a weird question. I try to keep my thermostat set on 75. Our electric bill is really high (around $400+ a month, during the summer) so I tried to keep it on 78 but it was just too hot, and my husband has COPD and emphysema, so he can't breathe when he gets too hot. Anyway. So during the hottest part of the day, when it's around 90 to 95 outside, the house is quite comfortable at 75. However, at night, when the temps drop to 70 to 75, the house is just awful. It's so hot. Last night, I went to bed about 3am, and my tee shirt was stuck to my back from all the sweat. Now does that make sense to you?

I'd think, logically, that it'd be hotter in the house during the day than during the night, but the night is often unbearable. Also, logic would dictate that 75 is 75, no matter what the temp is outside.

Also, let me reiterate - I run an extremely high electric bill. It's at least double, if not triple, of everyone else's here in the neighborhood. Now this is a brand new house, only about a year old. Last Sunday, we woke up and the house was really hot. We went outside to see if the unit was running, and it was, but along all the wires leading into the house, they were frozen solid. We turned off the AC and turned the unit strictly on fan, and left it on until the ice melted. Once the ice melted, the air started working again. We had the HVAC guy come out and he had to put in a couple of pounds of Freon and said he thinks we have a bad *something-or-other* part.

Would that have anything to do with us sweltering at night? Would it have anything to do with our electric bill being so much higher than everyone elses? I don't want to depend on this guy to tell me the truth, because of course he's going to say that everything's fine and I'm worried over nothing. My husband and my daughters both said that it's unbearably hot at night, but I don't dare turn the thermostat down below 75. I couldn't imagine what the bill would be.

I suffer the same situation in the house that I live. The theory I have come up with is that during the hot part of the day the AC is running much more so then at night. The air coming out of the AC vents is much cooler then what your thermostat is set at and it is circulating around the room to cool it. At night when its cooler outside and your AC isnt kicking on as much and it is not circulating that cooler air and so it feels warmer. I hope that makes sense :thinking.

 

[joko104]

What color is your roof? What type of foundation do you have? Is it brick/stone/stucco?

It sounds like something about your house is serving like a heat-sink (absorbing heat during the day.0 If you have a dark roof, a stone/stucco/brick wall taking a lot of sun (radiant heat) and/or a thick foundation pad (concrete) exposed to the sun, it is soaking up heat all day long, then is hot all night - cooled off by morning - and the cycle repeated. Thus your house will be hot when it is cool at night, but comfort during the day.

From what you have told, I also can predict your house is not shielded against the sun by trees, right?

Does this make sense to you?

 

[joko104]

You said what your problem is: "Attic explosively hot."

Then release the heat! Install roof vent turbines. They are cheap, cheap, cheap. Do it your self (just cut the holes with a saw, slide the high end under the shingles and caulk (tar) like crazy under and around the base and nail the base down (not many nails). You can add some vents into the overhang. You have likely DRAMATICALLY lowered the problem.

Gonna spend money? Have the underside of your roof from in the attic sprayed with silver reflectant, or install simple 1 inch thick form board with the SILVER SIDE UP to reflect back the radiant heat towards the roof and not the house.

If your roof shingles are DARK color, you particularly MUST address the roof/attic issue as it is soaking up massive heat like a solar hot water heater heating up the entire top of your house. Likely the same if you have a metal roof and it is not white or reflecting silver. How can your house stay cool if your roof is 160 degrees all day long - and then storing this in your attic - not just the air but all the structure of the attic too.

KEEP THE HEAT FROM BUILDING UP IN THE ATTIC BY VENTS. KEEP IT FROM GETTING THERE IN THE FIRST PLACE BY REFLECTING MATERIAL UNDER THE ROOF IN THE ATTIC. Watch your electric bill drop by 40% or more. And if you plan to stay there, plant FAST growing trees that will shade the roof and landscaping along the house that will shield the walls.

It is the RADIANT heat, not the air temperature, that most heats a house.

 

[Superfly]

What color is your roof? What type of foundation do you have? Is it brick/stone/stucco?

It sounds like something about your house is serving like a heat-sink (absorbing heat during the day.0 If you have a dark roof, a stone/stucco/brick wall taking a lot of sun (radiant heat) and/or a thick foundation pad (concrete) exposed to the sun, it is soaking up heat all day long, then is hot all night - cooled off by morning - and the cycle repeated. Thus your house will be hot when it is cool at night, but comfort during the day.

From what you have told, I also can predict your house is not shielded against the sun by trees, right?

Does this make sense to you?

It's a medium brown shingle roof. The foundation is slab. It's stucco on the front and vinyl siding on the sides and back. The setting sun hits us from the front left, and there are not lots of trees in that section. When the builder cleared the lot, we stood here and made sure that they left as many trees as they could, but there just were not that many on the front part of the lot.

 

[Superfly]

You said what your problem is: "Attic explosively hot."

Then release the heat! Install roof vent turbines. They are cheap, cheap, cheap. Do it your self (just cut the holes with a saw, slide the high end under the shingles and caulk (tar) like crazy under and around the base and nail the base down (not many nails). You can add some vents into the overhang. You have likely DRAMATICALLY lowered the problem.

Gonna spend money? Have the underside of your roof from in the attic sprayed with silver reflectant, or install simple 1 inch thick form board with the SILVER SIDE UP to reflect back the radiant heat towards the roof and not the house.

If your roof shingles are DARK color, you particularly MUST address the roof/attic issue as it is soaking up massive heat like a solar hot water heater heating up the top of your house.

KEEP THE HEAT FROM BUILDING UP IN THE ATTIC. KEEP IT FROM GETTING THERE IN THE FIRST PLACE. Watch your electric bill drop by 40% or more. And if you plan to stay there, plant FAST growing trees that will shade the roof and landscaping along the house that will shield the walls.

It is the RADIANT heat, not the air temperature, that most heats a house.

OK. I'm going to try to explain this, and I don't know a lot of what I am talking about, so please bear with me. When we were doing our final walkthrough, and we walked into the attic, we noticed light coming in from the edge of the attic. I was concerned that the roof was "off" and birds or bugs would fly in the attic, but she explained to me that it was a soffit, and vented. So I looked outside at the roof overhang and noticed a vented soffit (am I saying it right?). Do I still need to install attic fans or whatever?

 

[joko104]

If your bill is triple I would have the electric company come out and track down where the draws are. You might have a short somewhere. If you have a new house the AC should be under warranty. I would check to make sure all the ducts are sealed. My mom had a duct that was open into the attic and she had high electric bills as she was cooling the attic. Check the evaporator coils on the ac unit and make sure they are clean and the airflow is unrestricted though them. AS your unit was said to be low on refrigerant then there is a leak that needs to be corrected. Coils freezing up is generally due to low Freon, restricted airflow, and bad drainage for the condensate water. As far as nighttime temps set your thermostat to just below the average nighttime temp for the season and the ac will dry the air, reducing the humidity.

Definitely have the electric company come out. A badly shielded underground wire can literally be bleeding off electricity to earth.

 

[Removable Mind]

OK I have a weird question. I try to keep my thermostat set on 75. Our electric bill is really high (around $400+ a month, during the summer) so I tried to keep it on 78 but it was just too hot, and my husband has COPD and emphysema, so he can't breathe when he gets too hot. Anyway. So during the hottest part of the day, when it's around 90 to 95 outside, the house is quite comfortable at 75. However, at night, when the temps drop to 70 to 75, the house is just awful. It's so hot. Last night, I went to bed about 3am, and my tee shirt was stuck to my back from all the sweat. Now does that make sense to you?

I'd think, logically, that it'd be hotter in the house during the day than during the night, but the night is often unbearable. Also, logic would dictate that 75 is 75, no matter what the temp is outside.

Also, let me reiterate - I run an extremely high electric bill. It's at least double, if not triple, of everyone else's here in the neighborhood. Now this is a brand new house, only about a year old. Last Sunday, we woke up and the house was really hot. We went outside to see if the unit was running, and it was, but along all the wires leading into the house, they were frozen solid. We turned off the AC and turned the unit strictly on fan, and left it on until the ice melted. Once the ice melted, the air started working again. We had the HVAC guy come out and he had to put in a couple of pounds of Freon and said he thinks we have a bad *something-or-other* part.

Would that have anything to do with us sweltering at night? Would it have anything to do with our electric bill being so much higher than everyone elses? I don't want to depend on this guy to tell me the truth, because of course he's going to say that everything's fine and I'm worried over nothing. My husband and my daughters both said that it's unbearably hot at night, but I don't dare turn the thermostat down below 75. I couldn't imagine what the bill would be.

Super...half of our house is 80 years old...and the other half way newer. Our house is stone and cedar in the older part and we elected to do Hardi-Plank Colonial Rough Sown style siding (concrete/fiberglass material)....and cedar beams and trim. We have a metal roof...over both the old and newer sections.

The older part...I built a roof over the original roof for space to put duct work for central heat and air. I did layer in insulation between the two roofs. And havent really updated the insulation in 25 years. The newer side...is well insulated.

We originally had a conventional central heat/air conditioner. A few years ago, we purchased a "Heat Pump". Our electric bills use to run about the same as yours until we got the Heat Pump...now the highest bills for heat and or AC has not yet hit $200 a month...and we keep our temp at 72 in the summer and about 75 to 78 in the winter.

I suspect one of a few things are going on since your house is a year old. One is that the central AC unit is too small. Or the unit you have is defective or wasn't charged properly at the factory. Or...the evaporator coil isn't removing the moisture from the air properly. And that's usually because of too low of a level of coolant in the unit.

The other thing left is proper insulation throughout the house...based on the construction materials used to build your house. The walls need a certain R value to reduce heat or cold from effecting air temps inside. The same applies for the attic. It's probably easy to check the attic to see what was placed in there and calculate the R value to see if it's enough. The walls...well, you would have to make an opening in some area...and it would be more likely to test on the west side of your house.

I can't really think of more things to consider...and there could well be, but I'm not an AC expert, but my step-daughter's significant other - he is. And we talked about what we needed to do to keep our bills down while maintaining temps that we wanted. Sooooooooo, there you have my 2 cents worth.

 

[Removable Mind]

OK I have a weird question. I try to keep my thermostat set on 75. Our electric bill is really high (around $400+ a month, during the summer) so I tried to keep it on 78 but it was just too hot, and my husband has COPD and emphysema, so he can't breathe when he gets too hot. Anyway. So during the hottest part of the day, when it's around 90 to 95 outside, the house is quite comfortable at 75. However, at night, when the temps drop to 70 to 75, the house is just awful. It's so hot. Last night, I went to bed about 3am, and my tee shirt was stuck to my back from all the sweat. Now does that make sense to you?

I'd think, logically, that it'd be hotter in the house during the day than during the night, but the night is often unbearable. Also, logic would dictate that 75 is 75, no matter what the temp is outside.

Also, let me reiterate - I run an extremely high electric bill. It's at least double, if not triple, of everyone else's here in the neighborhood. Now this is a brand new house, only about a year old. Last Sunday, we woke up and the house was really hot. We went outside to see if the unit was running, and it was, but along all the wires leading into the house, they were frozen solid. We turned off the AC and turned the unit strictly on fan, and left it on until the ice melted. Once the ice melted, the air started working again. We had the HVAC guy come out and he had to put in a couple of pounds of Freon and said he thinks we have a bad *something-or-other* part.

Would that have anything to do with us sweltering at night? Would it have anything to do with our electric bill being so much higher than everyone elses? I don't want to depend on this guy to tell me the truth, because of course he's going to say that everything's fine and I'm worried over nothing. My husband and my daughters both said that it's unbearably hot at night, but I don't dare turn the thermostat down below 75. I couldn't imagine what the bill would be.

By the way...Soffit Vents...a good thing. You should see light. There are baffles to keep the insulation from covering the vents.