WWYD AC/furnace repairs

[bobosensei]

My boyfriend scheduled an AC tuneup for 2 of the 3 units in the house. We never use the one downstairs. He thinks they don't cool the house quickly enough or keep it cool long enough, but he has it on a nest timer to only come on late in the afternoon. It's been fine until we hit a stretch of 90+ weather and we just run them longer, but I've always been told that AC can only reasonably cool the inside 20 degrees from outside temps so I didn't really feel there was an issue.

Anyway the guy comes out and the good news is we don't have freon leaks. Because of the ban on R22 in 2020 we do know we will have to replace the units that were last done in 2012 if/when this becomes an issue. They were dirty, and he gave a few options. He said the upstairs could go at any time, but didn't really say why.  Just that he hooks up something and expects a reading of 45 and gets a 5.  The other one wasn't as bad, but he never actually told me the output.  He just recommended replacing contactors and adding some sort of battery assisting. The quote to clean and add a battery was 852, quote to do that plus replace contactors and add a jumpstart battery was 1500, and full system replacement (just one not both but would include furnace was 9-19k even though he told me verbally 6-12k when he was in the house). He said one of the furnaces has a cracked heating exchanger, but he didn't remove the cover. He just saw a small crack like less than a mm by a screw and said that means it is probably cracked somewhere on the heat exchanger too.  I asked him what he would do and he said he thought replacing all the stuff on the ACs would give us a few more years.  He didn't mention the furnace though he had said we shouldn't use it due to the danger of CO leaking into the house.

I didn't have the guy do anything. Boyfriend and I cleaned one of the AC units already with a hose and a can of cleaner, and have another can of cleaner to do the other one. We decided we can wait until there is an issue to do further work. As for the furnace I haven't made up my mind, but might lean towards adding another CO detector in the basement. The furnaces are 19, but are gas which I think has a longer life expectancy.  I may just have someone else come out to look at things in the fall and request that they actually look at the heat exchanger and make a decision then.

In the mean time I stopped my 250 a month contribution to brokerage account to put it in savings in case I am spending 3k on a new furnace this fall.  They guy quoted me 3k on the furnace which might be why the system replacement quote he sent was 3k higher.  I haven't heard bad things about this company but I don't see anyone in my neighborhood recommend them either.  They were just running this tune up special which it turns out they don't actually tune up anything they just check a bunch of things to tell you what is wrong so it feels like they might be trying to get whatever work they can from people even if it isn't warranted.

[Blonde Granny]

I would get a second opinion before I did anything.  BF and AC people are sometimes not to be trusted.

[resolution]

I think you should get a second opinion before you do anything. Its generally a good practice for large purchases, and in this case the amount of variance in the estimates seems large.

Back in 2008 I paid someone $700 to do an emergency repair to my HVAC, and at the time they recommended replacement. I had someone else look at it later and they said it was fine, so I let it go. It was fine for another 10 years. When I had to replace the unit earlier this year, I got a quote for $6600 and a quote for $4200 for similar units. It is a small house, so it just took one 4 ton unit that covered both heating and cooling.

[spartan7886]

Does your furnace have a safety shut off? My neighbor was our HVAC guy for years. He charged properly for the AC check, but would do the furnace check for a plate of cookies, since it was 10 minutes when you don't have travel time. The downside was we got our furnace check whenever he got around to it. That was usually after it started getting cold. He taught me how to check the safety shut off for CO by myself so we would feel better about it. I can't swear that your gas furnace works the same as mine, but something to think about. Basically, the furnace should always be operating at a lower pressure in the burner tubes than atmospheric. That forces any airflow through a crack to go from the attic into the unit rather than the other way around. There is a small rubber tube running from the burner area to the gauge. When I disconnect the tube and the gauge sees atmospheric pressure, the furnace shuts down, confirming everything is working properly. I reconnect it, wait a few minutes, the fans start running, the gauge sees the correct pressure, and the burners kick back on.

[Deleted]

Yep.  Get a second opinion.  DH and I had a service agreement with a very large local HVAC company for years- we paid $10/month, they came out twice a year to check the heating and A/C and gave us priority on emergency calls.  When we moved across the state line we continued with them but somehow the crew here ALWAYS finds things to make and do and their prices are crazy high.  They're polite, they're well-spoken, they put on little booties so they don't mess up your floors... but I no longer trust them.  They were charging over $200 for the required annual testing of our sprinkler system backflow valve.  Last year I found a place that charged $50.  They found that the garbage disposal in the downstairs kitchen wasn't working but would replace it for $540.  No, thanks.

This year they checked out the A/C and said that the unit needed cleaning or I could blow a coil in the peak A/C season.  They'd clean the unit and replace the corroded flue pipe for $672.    A local plumber wrapped the pipe (it had only a few rusty spots on it- unit only 4 years old)  for $100 when he was doing other work, and agreed that hosing the unit down following directions on a 5-minute YouTube video I found was all the outside unit needed.  Oh yeah- Big Company now sends a nice guy out to check my electrical stuff.  They found a faulty GFI circuit in the guest bathroom outlet.  That means that if someone sits in the bathtub using an electric hair dryer plugged into it and it drops into the water, they may get electrocuted.  They'll replace it for $500.

It's a jungle out there.

[thyme4change]

I live in Phoenix. Maybe your a/c can only cool down the house 20 degrees, but mine will keep it around 70, even if it is 118 degrees outside. It might be able to go lower, but I haven't tried.

[Deleted]

Are these window units or something that you have 3 of them in a townhouse?   I have a large house with one central air unit and it can definitely cool more than a 20 degree difference.   I suppose how well the house is insulated is a big factor.  

[countrygirl2]

We spent $1300 on a new coil for our furnace.  It got to making a loud racket and water was coming out so we knew something was wrong.  It also had not be heating right I didn't think and was not cooling down.  We have had this small local company work on all our houses we think they do a good job.  I know since he fixed it, it is really nice in here so I'm sure we needed it.  I hate to not be able to trust companies.

$500 for breaker, holy cow!  Maybe $20 for the new receptacle, some of these people are crazy.

[alabamagal]

The best money saving is to not replace until it is broke. Cleaning the coils will help the efficiency, the other things are just replacement parts, wouldn’t even do that until broken.

Take the ACs off the nest systems and let them run during the day. The units are sized to run to cool your house, by letting the house heat up they just have to run longer in the afternoon. You are probably saving pennies per day doing that (I could give you an engineering explanation on heat transfer, but won’t).

The other reason that you should just run them until they die is that you have 3 units. If one of them dies, you have rooms you can hang out in until you get a replacement.

[tskeeter]

Jun 3, 2019 6:47:46 GMT -5 bobosensei said:

My boyfriend scheduled an AC tuneup for 2 of the 3 units in the house. We never use the one downstairs. He thinks they don't cool the house quickly enough or keep it cool long enough, but he has it on a nest timer to only come on late in the afternoon. It's been fine until we hit a stretch of 90+ weather and we just run them longer, but I've always been told that AC can only reasonably cool the inside 20 degrees from outside temps so I didn't really feel there was an issue.

Anyway the guy comes out and the good news is we don't have freon leaks. Because of the ban on R22 in 2020 we do know we will have to replace the units that were last done in 2012 if/when this becomes an issue. They were dirty, and he gave a few options. He said the upstairs could go at any time, but didn't really say why.  Just that he hooks up something and expects a reading of 45 and gets a 5.  The other one wasn't as bad, but he never actually told me the output.  He just recommended replacing contactors and adding some sort of battery assisting. The quote to clean and add a battery was 852, quote to do that plus replace contactors and add a jumpstart battery was 1500, and full system replacement (just one not both but would include furnace was 9-19k even though he told me verbally 6-12k when he was in the house). He said one of the furnaces has a cracked heating exchanger, but he didn't remove the cover. He just saw a small crack like less than a mm by a screw and said that means it is probably cracked somewhere on the heat exchanger too.  I asked him what he would do and he said he thought replacing all the stuff on the ACs would give us a few more years.  He didn't mention the furnace though he had said we shouldn't use it due to the danger of CO leaking into the house.

I didn't have the guy do anything. Boyfriend and I cleaned one of the AC units already with a hose and a can of cleaner, and have another can of cleaner to do the other one. We decided we can wait until there is an issue to do further work. As for the furnace I haven't made up my mind, but might lean towards adding another CO detector in the basement. The furnaces are 19, but are gas which I think has a longer life expectancy.  I may just have someone else come out to look at things in the fall and request that they actually look at the heat exchanger and make a decision then.

In the mean time I stopped my 250 a month contribution to brokerage account to put it in savings in case I am spending 3k on a new furnace this fall.  They guy quoted me 3k on the furnace which might be why the system replacement quote he sent was 3k higher.  I haven't heard bad things about this company but I don't see anyone in my neighborhood recommend them either.  They were just running this tune up special which it turns out they don't actually tune up anything they just check a bunch of things to tell you what is wrong so it feels like they might be trying to get whatever work they can from people even if it isn't warranted.

The 20 degree temp reduction is for a swamp cooler, not for A/C.  With A/C you recirculate the air many times, and the air becomes a little cooler each time it goes across the cooling coils, until the air reaches the temp the thermostat is set at.

[phil5185]

GFI - they cost about $20 at Ace Hardware. 3 wires to install, pull your breaker, remove & replace the GFI , snap the breaker back 'On'.

encrypted-tbn1.gstatic.com/shopping?q=tbn:ANd9GcRW9CEL0s_9leuTrdkkDNVLhwb7GEtbPPIg0XyUEQKgNASEiPkBUn67Uh4MqIfItz89DQ02fCP7JBY&usqp=CAc

I've always been told that AC can only reasonably cool the inside 20 degrees from outside temps so I didn't really feel there was an issue.

Test for at least 20 degrees between an air outlet duct and the air return screen.  Eg, when your return air is 75, the ducts should run at 55 or lower.  The outside temperature isn't the big factor, the AC is a closed system - air in, air out.   In Arizona, we sometimes see  80-in/65-out when the outside temp is 115 degrees, the AC can't quite maintain a 20 degree differential - the heat load thru the walls/windows is high during daytime hours.

The best money saving is to not replace until it is broke. Cleaning the coils will help the efficiency, the other things are just replacement parts, wouldn’t even do that until broken.

The units are sized to run to cool your house, by letting the house heat up they just have to run longer in the afternoon. You are probably saving pennies per day doing that (I could give you an engineering explanation on heat transfer, but won’t).

  That's what we do. On one rental house the unit ran 28 years, I never touched it for the whole time. Most of the other houses need a condenser motor every decade or so - or an occasional recharge.  Ours are all roof-mount units. The latest one on our home was a 4 ton heat pump, lasted 16 years, I never serviced it.  BTW, the houses with separate AC/furnace setups last longer than the heat pump units (that run the compressor for 12 months rather than 6).

[schildi]

Jun 3, 2019 18:54:33 GMT -5 alabamagal said:

The units are sized to run to cool your house, by letting the house heat up they just have to run longer in the afternoon. You are probably saving pennies per day doing that (I could give you an engineering explanation on heat transfer, but won’t).

I would not mind hearing that explanation.

[bobosensei]

Jun 3, 2019 13:30:31 GMT -5 spartan7886 said:

Does your furnace have a safety shut off? My neighbor was our HVAC guy for years. He charged properly for the AC check, but would do the furnace check for a plate of cookies, since it was 10 minutes when you don't have travel time. The downside was we got our furnace check whenever he got around to it. That was usually after it started getting cold. He taught me how to check the safety shut off for CO by myself so we would feel better about it. I can't swear that your gas furnace works the same as mine, but something to think about. Basically, the furnace should always be operating at a lower pressure in the burner tubes than atmospheric. That forces any airflow through a crack to go from the attic into the unit rather than the other way around. There is a small rubber tube running from the burner area to the gauge. When I disconnect the tube and the gauge sees atmospheric pressure, the furnace shuts down, confirming everything is working properly. I reconnect it, wait a few minutes, the fans start running, the gauge sees the correct pressure, and the burners kick back on.

I'm not sure about that. It's been too hot for me to want to turn the furnace back on to check this.  But I think I will wait until it is closer to fall check this and decide if someone should come out.

[bobosensei]

Jun 3, 2019 14:52:55 GMT -5 @athena53 said:

That means that if someone sits in the bathtub using an electric hair dryer plugged into it and it drops into the water, they may get electrocuted.  They'll replace it for $500.

 yeah, I never know when people are saying ridiculous things to me because I am a woman or because they see the neighborhood where I live and think I have money to burn.  I've gotten a lot of ridiculous quotes for things.  One guy wanted 700 to spread pine straw on a few flowerbeds.  Another said 400 for mulch.  I ended up buying more mulch than the second guy said I would need for 150 bucks and just doing the work myself.  400 did seem reasonable though.  I just don't have time to hem and haw and get a million quotes for things.  I don't know who does if you work a full time job and have a commute.  But in general I hate sales people and I know when someone comes out to give a quote they are trying to sell services.  I'm sure that AC guy has some incentive to get people to do work whether it is commission or bonus based.

[bobosensei]

Jun 3, 2019 18:13:01 GMT -5 minnesotapaintlady said:

Are these window units or something that you have 3 of them in a townhouse?   I have a large house with one central air unit and it can definitely cool more than a 20 degree difference.   I suppose how well the house is insulated is a big factor.  

I'm not  in a townhouse.  It is a 3200 square foot single family home.  Insulation is fine.  I asked the guy who inspected as well as the AC guy and both said I had way more than enough in the attic.  I do have a lot of windows, and spent 900 on three remote operated double cell shades on windows that are 18-20 feet up in my living room.  I think that helped some as those windows face northwest and dumped afternoon sun in half the downstairs so this is the first summer I've had the shades but hoping to see a difference in my bill.  For electric last summer the bills were 160-200 depending on how many weeks in the cycle.  The most I've had this year is 130, but we aren't in the full swing of summer in the south though we did hit a stretch of 90+ degree weather these last few weeks.  August will be worse so waiting to see then if the shades really help.

I believe the basement was finished after the house was built and would be why they put a third unit in, but I have a unit for each floor which I guess is normal though does seem ridiculous?  I don't use the one in the basement at all.  Even if I used the basement more I don't think I'd really need AC there.  I tried to find the size of the units but can't right now.  I just know the one on the main floor is smaller by a half ton.  

[bobosensei]

Jun 3, 2019 20:09:26 GMT -5 phil5185 said:

GFI - they cost about $20 at Ace Hardware. 3 wires to install, pull your breaker, remove & replace the GFI , snap the breaker back 'On'.

encrypted-tbn1.gstatic.com/shopping?q=tbn:ANd9GcRW9CEL0s_9leuTrdkkDNVLhwb7GEtbPPIg0XyUEQKgNASEiPkBUn67Uh4MqIfItz89DQ02fCP7JBY&usqp=CAc

I've always been told that AC can only reasonably cool the inside 20 degrees from outside temps so I didn't really feel there was an issue.

Test for at least 20 degrees between an air outlet duct and the air return screen.  Eg, when your return air is 75, the ducts should run at 55 or lower.  The outside temperature isn't the big factor, the AC is a closed system - air in, air out.   In Arizona, we sometimes see  80-in/65-out when the outside temp is 115 degrees, the AC can't quite maintain a 20 degree differential - the heat load thru the walls/windows is high during daytime hours.

The best money saving is to not replace until it is broke. Cleaning the coils will help the efficiency, the other things are just replacement parts, wouldn’t even do that until broken.

The units are sized to run to cool your house, by letting the house heat up they just have to run longer in the afternoon. You are probably saving pennies per day doing that (I could give you an engineering explanation on heat transfer, but won’t).

  That's what we do. On one rental house the unit ran 28 years, I never touched it for the whole time. Most of the other houses need a condenser motor every decade or so - or an occasional recharge.  Ours are all roof-mount units. The latest one on our home was a 4 ton heat pump, lasted 16 years, I never serviced it.  BTW, the houses with separate AC/furnace setups last longer than the heat pump units (that run the compressor for 12 months rather than 6).

I do remember when I bought last year that in the inspection the air from the vent was in the 50s.  I'll try to see if I can measure the temp when it kicks on today.  I have a thermometer for the oven that I might be able to get a reading from.  The air feels cool.  Like I told the AC guy I didn't really think we had an issue, but agreed that if we won't be able to get r-22 next year it made sense to check for leaks now when we could do a limp along repair if needed.

[thyme4change]

Jun 4, 2019 0:07:31 GMT -5 schildi said:

Jun 3, 2019 18:54:33 GMT -5 alabamagal said:

The units are sized to run to cool your house, by letting the house heat up they just have to run longer in the afternoon. You are probably saving pennies per day doing that (I could give you an engineering explanation on heat transfer, but won’t).

I would not mind hearing that explanation.

After years of me not understanding someone explained it to me like this...

When a house heats up and sits for a few hours, everything in it heats up - the mattresses, couches, flooring, drywall, etc. Then you turn on the a/c and it heats the air that is floating around, sees that it got cooler and shuts off. However, the heat trapped in the furniture and structure finds that the air next to them is cooler, so it starts seeking equilibrium by letting the hot air seep out. The a/c realizes the air is warm and switches on again, and runs until that air is cool. Once again, the recliner, the books in the bookshelf and all the clothes in your closet start dumping their hot air into the cool air, and the cycle begins again. This goes on until all the parts of the house are the same temperature as the general air.

I have been told many times that it is more efficient to keep the whole house within a couple of degrees of your normal level. I can't prove that, but I am sure someone has.

Even if the a/c has to run the same amount of time during the day to keep things cool as it would to cool the house down when you get home, and it is a wash, it is way more comfortable to walk into a comfy house than to sit there for an hour while your unit cycles on continuously to bring the house down to the right temp.

[Blonde Granny]

After my DH passed away and my house was 2 years old I had a well know HVAC company come out to give me a price to make a couple of changes. Let's see, I was told the AC and the gas furnace were not the same BTU sis, and that the duct work running through the attic was not the same size and the "not same size HVAC units). But that all could be fixed. The price for all this was $10K, and don't forget, all this was on a 2 year old house.

I even had a guy neighbor here and they still tried all this nonsense. I explained I was a widow and unable to pay such a cost and that I could heat and cool this house for a long time for $10K. However, my biggest problem is still the AC. Regardless of what the thermostat is set on, when using the AC it simply won't turn off.....it just runs and runs and runs. Getting completely fed up, I grabbed a little electric fan, put in on top of a small decorative box and aimed the air straight at the thermostat. Problem solved!!!!!!!! Fan comes out in the summer and is put in the closet during the winter.

[countrygirl2]

You likely just need a new thermostat, they aren't always good.  We had a furnace checked over and over and over.  Wouldn't work right.  I finally told the supervisor when he came out that no one had checked the thermostat, they had not.  He replaced it, end of problems, this was a new furnace.


And I had one same issue one time.  I took the cover off and there was dirt in there, I blew it out, issue solved.

[phil5185]

""I have been told many times that it is more efficient to keep the whole house within a couple of degrees of your normal level. I can't prove that, but I am sure someone has.

Even if the a/c has to run the same amount of time during the day to keep things cool as it would to cool the house down when you get home, and it is a wash, it is way more comfortable to walk into a comfy house than to sit there for an hour while your unit cycles on continuously to bring the house down to the right temp.""

It is better not to adjust the set-point within a 24 hour diurnal cycle.  But if you are going to be gone for 2 days or more, you save money by moving the set-point up 10 or 15 degrees.  (I'm sure that the people who market programmable t-stats won't like that.)

[tskeeter]

Jun 4, 2019 6:51:16 GMT -5 bobosensei said:

Jun 3, 2019 18:13:01 GMT -5 minnesotapaintlady said:

Are these window units or something that you have 3 of them in a townhouse?   I have a large house with one central air unit and it can definitely cool more than a 20 degree difference.   I suppose how well the house is insulated is a big factor.  

I'm not  in a townhouse.  It is a 3200 square foot single family home.  Insulation is fine.  I asked the guy who inspected as well as the AC guy and both said I had way more than enough in the attic.  I do have a lot of windows, and spent 900 on three remote operated double cell shades on windows that are 18-20 feet up in my living room.  I think that helped some as those windows face northwest and dumped afternoon sun in half the downstairs so this is the first summer I've had the shades but hoping to see a difference in my bill.  For electric last summer the bills were 160-200 depending on how many weeks in the cycle.  The most I've had this year is 130, but we aren't in the full swing of summer in the south though we did hit a stretch of 90+ degree weather these last few weeks.  August will be worse so waiting to see then if the shades really help.

I believe the basement was finished after the house was built and would be why they put a third unit in, but I have a unit for each floor which I guess is normal though does seem ridiculous?  I don't use the one in the basement at all.  Even if I used the basement more I don't think I'd really need AC there.  I tried to find the size of the units but can't right now.  I just know the one on the main floor is smaller by a half ton.  

Three units makes it much easier to heat the house evenly.  Avoids the tendency for top floor to be too hot and lower floor to be too cool.  The basement system might be there more for dehumidification than cooling.

[countrygirl2]

They tell us on our geothermal just leave it alone.  If you move it more then 2 degrees it takes a lot of power to take it up or down beyond that and auxiliary heat comes on.  That's the most we move it anyway.


Our furnace guy and I were talking about ours being 16 years old.  He said the loop in the ground would likely last 40 to 50 years.  A whole furnace, not that part, would cost likely $16k.  But he said I would just piece meal fix it, blowers, whatever else, maybe $500 or so each.  He said only if the compressor goes would he consider doing more.  I'm sure that's what we will do.

We were going to turn it off with the cool weather but just decided to leave it alone.  These geo thermal systems are nice, not outside AC unit or anything.


Yep and I doubt we move unless a recession hits.  Hubs is right the type of home I would move to is likely to be $300k, well this one is, so yeah, I can see that.  Maybe put in an elevator here, he has talked about it so we can use the basement later.  Or if we see one of the really nice ones in town come up for sale.  I think it would be cheaper to spruce up then build also.  Plus the hassle would be something else.  He would be wanting to do everything to save money himself and would slow the progress to zero.

 

[schildi]

Jun 4, 2019 11:52:16 GMT -5 phil5185 said:

""I have been told many times that it is more efficient to keep the whole house within a couple of degrees of your normal level. I can't prove that, but I am sure someone has.

Even if the a/c has to run the same amount of time during the day to keep things cool as it would to cool the house down when you get home, and it is a wash, it is way more comfortable to walk into a comfy house than to sit there for an hour while your unit cycles on continuously to bring the house down to the right temp.""

It is better not to adjust the set-point within a 24 hour diurnal cycle.  But if you are going to be gone for 2 days or more, you save money by moving the set-point up 10 or 15 degrees.  (I'm sure that the people who market programmable t-stats won't like that.)

My understanding is that this (keeping temp constant) is only better in the case of heating with a heat pump - AND when you set the system such that it will use "emergency heat" when the temp difference between room temp and thermostat setting is more than a certain number of degrees (as would be the case when you come home to a cold house and crank up the thermostat by 10 degrees).

In all other cases, your house is a system that loses heat (= energy) to it's surrounding area. The furniture, carpet, walls inside don't really matter, they are part of the system. Fact is that this system (your house) exchanges heat (for you that's a loss) with the outside environment. And that exchange depends on the temp difference between your house and the environment. The greater the (average) temp difference, the greater the heat (or cold) "loss". That's physics, thermodynamics. Nothing you can do about it (besides turn down the A/C or heat).

So with that, turning the heat (or cold) down any amount of time (like at night) will save you money, and it won't be "more efficient" to keep the same temperature 24/7. The exception being that heat pump example I mentioned. And that's also only true for short periods of time, a few hours. Anything longer and turning down the heat will save money. If you turn down the A/C (thermostat up) during the day when you are gone the A/C will overall run less time compared to leaving the setting constantly cold.

Now is it worth the savings? Everybody would have to experiment and decide. It's definitely more comfortable to come home to a fully conditioned home that's at a temp you like ....

A programmable thermostat is a good idea: turn on the A/C or heat half an hour before you get home. Heck, nowadays you can turn it on based on your proximity to home with your smart phone in case you come home early.

Do I have a misunderstanding here?

[phil5185]

"" Do I have a misunderstanding here? ""

Not really.  But the thermal inertia of all of the 'hard' materials (walls, floors, ceiling, furniture) in the house is way more heat inertia of the 500 pounds of free air in the house.   So when you turn the unit back on it has to run hard to heat/cool the air to the new set-point. And then it shuts off. The hard materials immediately a bunch of heat/cold into the air and cause the unit to come back on again. The unit may 'short cycle' in that mode for several hours until thermal equilibrium is reached between the air and the hard mat'ls.

[thyme4change]

When we go away and put the thermostat up, I notice the walls and furniture and stuff feel warm, even after the a/c has been cycling for an hour.

[countrygirl2]

2 or 3 degrees is about all we adjust ours.

[schildi]

I turn ours off and back on a half hour before returning home. Cost effective and still the right temperature.

[Deleted]

I stopped messing around with adjusting the temps for the AC several years ago and haven't seen any difference in my electric bills.  I just set it and forget it.  Sometimes it's on for weeks at a time.   I do check late every night and will shut it off and open all the windows if it cooled down outside and then close it all up again in the morning with the AC set on it's normal 72. 

Our problem more than the heat is the humidity.  I like to keep that down inside the house.  I don't think it's good for all the woodwork and I don't like sweating toilets and moldy bread. 

I do use the programmable thermostat for the furnace though.  About the only time I have it set warm (and to me that's 65-66) is in the evenings after we get home and in the early morning right before we get up.  Other than that, it defaults back to 58. 

[countrygirl2]

75 and 76 summer, same in winter.  Now its running good again looks like our electric bill is going up slowly, bet that thing has been bad for some time.  And none of the fault lights came on, yikes!

[kadee79]

Jun 4, 2019 9:20:06 GMT -5 thyme4change said:

Jun 4, 2019 0:07:31 GMT -5 schildi said:

I would not mind hearing that explanation.

After years of me not understanding someone explained it to me like this...

When a house heats up and sits for a few hours, everything in it heats up - the mattresses, couches, flooring, drywall, etc. Then you turn on the a/c and it heats the air that is floating around, sees that it got cooler and shuts off. However, the heat trapped in the furniture and structure finds that the air next to them is cooler, so it starts seeking equilibrium by letting the hot air seep out. The a/c realizes the air is warm and switches on again, and runs until that air is cool. Once again, the recliner, the books in the bookshelf and all the clothes in your closet start dumping their hot air into the cool air, and the cycle begins again. This goes on until all the parts of the house are the same temperature as the general air.

I have been told many times that it is more efficient to keep the whole house within a couple of degrees of your normal level. I can't prove that, but I am sure someone has.

Even if the a/c has to run the same amount of time during the day to keep things cool as it would to cool the house down when you get home, and it is a wash, it is way more comfortable to walk into a comfy house than to sit there for an hour while your unit cycles on continuously to bring the house down to the right temp.

We are on an electric coop.  Back when we built the house, the guys from the coop who hooked us up said to keep the house at the same temp inside year round to save $$...due to exactly what T4C is saying...if the unit doesn't have to cool or heat the walls, the doors, the furniture...it uses less energy in the long run.
And insulation isn't just in the ceiling/attic...what you have in your walls can also make or break a heating/cooling unit.  Ours is very well insulated and it has made a difference.  While many in the area have $300-$400 power bills in our summer heat...we have between $120-$200!  Our house is almost 1900 sq. ft., a single story ranch with no basement...ground water levels too high in this area for basements.