Normal A/C on / off cycle durations?

Well, that depends on whether we're recovering the latent heat from condensing the water.

Oh wait, we had this conversation with Stormy. never mind.

Reply to
TimR
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On Mon 01 May 2017 07:14:03a, Mike Name told us...

A lot depends on where you live. We live in the Arizona desert and our typical daytime summer temperatures can range from 105? F. to 120? F. Our night time temperatures can still be as high as 100? F. Our humidity levels are extremely low, so the differential temperature for comfort is usually about 77-78? F. Set much lower than that it begins to feel like a freezer.

When we lived in Ohio with high relative humidity and temperatures in the high 80s to the mid 90s, I recall setting our thermostat to anywhere from 72? F. to 75? F.

Reply to
Wayne Boatwright

replying to Mike Name, Djayhan wrote: Thank you, that's about the only sentence that makes sense on this page.

Reply to
Djayhan

replying to trader_4, Djayhan wrote: A little exaggerated like 100 degrees too, but 78 degrees seems pretty pointless if you own an AC unit. 72° is considered be optimal 10 picture for human beings to dwell in so why have been air conditioning unit attached to your house if you're not gonna use it at optimum and temperatures or another words he so conservative that you're never comfortable live a little and let your $ serve you.

Reply to
Djayhan

There are plenty of places in North American that are common with 100 degrees in summer. Keeping the house at 78 and dry is quite comfortable. Less shock to the body going in and out too.

Human comfort varies. 72 is not bad is summer, but in winter I like 65 for sleeting 70 for the rest of the day.

Reply to
Ed Pawlowski

Denco - AC - Carrier dealer you know I am from California and just had a new AC condenser, coil and furnace replaced. I am experiencing exactly the same as one of your customer after upgrading my AC to a 4t from a 3t unit, it now running like 8-10 mins and shuts down from 18 - 22 mins. But I was wondering cause I have not seen my electric bill after this installation, would this lower or raise my electricity bill?Thanks

Reply to
Vld5491

If it's doing that when temps are moderate, it's probably fine. If it's doing that when temps are hot, then it's oversized. Was there a problem with the existing 3T not cooling enough? What was the reason for going larger? As to the electric bill, probably won't make any significant difference due to the timing. It will use less electricity if it replaced an old honker. The big downside to oversizing is that it won't run enough to remove humidity on moderate days, won't run as long as it should to mover air around and get balanced, etc.

Reply to
trader_4

replying to trader_4, Vld5491 wrote: We decided to upgrade from 3t to 4t because we have a townhouse with 1708 sqft. We had to close 3 registers/vents to get out 3 bedrooms to get to comfortable level. Plus the contractor says in every 400 sq ft requires 1 tonage. With regards to humidity here in CA we have a very low humidity and we are still on moderate weather, summer starts in June. Another thing that came to mind is the frequency of the ac going on and off. Is this not bad for the unit? Well the ac cool up pretty fast comparing to our old honker that's for sure. Thanks for your infos. Have a wonderful memorial weekend?

Reply to
Vld5491

3 tons should be plenty for 1700 so ft.

We had to close 3 registers/vents to get out 3 bedrooms to get to

Probably because something is wrong with the system, design, etc.

Plus the contractor says in every 400 sq ft requires 1

That contractor is an idiot. Following that logic, a 2500 so ft house needs 6 tons? A 3000 so ft needs 7+ tons? You can do a manual J calculation whi ch factors in size, insulation,windows, exposure, climate to get a correct number. That's why you have a system that is short cycling.

With regards to humidity here in CA we have a very low humidity and we

It's less stress on the system and more energy efficient if it's correctly sized, that's true. But it doesn't mean that it's going to burn up or use a lot more energy either. I'd be more concerned about having it run enough t o get an even temp.

ell the ac cool up pretty fast comparing to our old honker that's for

Reply to
trader_4

I have 2100 sq. ft. and cool it with 2 1/2 ton. Of course, conditions vary and the contractor should have run the manual J calculations.

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Agree on the idiot part.. Looks like the OP will have a cold muggy summer.

Reply to
Ed Pawlowski

replying to trader_4, Vld5491 wrote: Thank you so much for the infos. Have a nice day?

Reply to
Vld5491

replying to Mike Name, JoeBlow wrote: We keep our thermostat set on 78 in the summer. If we were to set it at 73 we would have to wear sweatpants and socks just to keep from freezing! 73 is what our basement temp is and it's too chilly down there. I like sitting around in my underwear and a t-shirt during the summer, so 73 would be too cold. Plus, we don't want to give any more money to the energy company than we have to! In the winter we set it on 67 and bundle up in sweat pants and sweat shirt and socks. Plus, when I'm sitting down, I have a blanket covering my feet and legs.

Reply to
JoeBlow

On Thu 13 Jul 2017 04:14:02a, JoeBlow told us...

We keep our thermostat set at 77?F. year round. If we want to feel cooler than that, we switch on the ceiliong fans.

Reply to
Wayne Boatwright

The question was about short cycling and how he could determine if his was short cycling. Most of the posts here were about what temp is comfortable a nd other useless information. I love the "wrong again" comment. That was al so helpful especially without a reason. I'm pretty sure my one year old, 7K , 2.5 ton system is too big for my 720 square foot house. I had the compres sor and outdoor components exchanged for 2 ton components within two weeks. The humidity is always in the upper fifties so it never feels good. Anothe r sign it's too big. Not surprisingly, the blower motor went out at 12 mont hs. I was lead to believe it was a manufacturing problem. Doesn't take a ge nious to figure out a system turning off and on too often will also cause w ear and tear. Which leads us back to the original question....how short is too short? It was hot here in Chicago yesterday, 85, and my newly repaired A/C was on 7 minutes and off 7 minutes which I felt was too short. Still at a loss given the info here. It was hot, am I wrong in thinking it was too short? BTW, I realize insulation, window and door leaks must factor in. Fou r years ago I had 8 inches of insulation blown the attic. My old two ton A/ C never had such short cycles, not even with 4 inches of insulation. I unde rstand on a hot day 10 minutes on and 10 minutes off or three cycles an hou r could be appropriate from info I got elsewhere. Anyone agree? Comments? I can't replace worn out parts every year.

Reply to
patricialnemec

On Sunday, September 17, 2017 at 12:24:31 PM UTC-4, snipped-for-privacy@gmail.com wr ote:

s short cycling. Most of the posts here were about what temp is comfortable and other useless information. I love the "wrong again" comment. That was also helpful especially without a reason. I'm pretty sure my one year old,

7K, 2.5 ton system is too big for my 720 square foot house. I had the compr essor and outdoor components exchanged for 2 ton components within two week s. The humidity is always in the upper fifties so it never feels good. Anot her sign it's too big. Not surprisingly, the blower motor went out at 12 mo nths. I was lead to believe it was a manufacturing problem. Doesn't take a genious to figure out a system turning off and on too often will also cause wear and tear. Which leads us back to the original question....how short i s too short? It was hot here in Chicago yesterday, 85, and my newly repaire d A/C was on 7 minutes and off 7 minutes which I felt was too short. Still at a loss given the info here. It was hot, am I wrong in thinking it was to o short? BTW, I realize insulation, window and door leaks must factor in. F our years ago I had 8 inches of insulation blown the attic. My old two ton A/C never had such short cycles, not even with 4 inches of insulation. I un derstand on a hot day 10 minutes on and 10 minutes off or three cycles an h our could be appropriate from info I got elsewhere. Anyone agree? Comments? I can't replace worn out parts every year.

Find a thermostat that lets you adjust how often it runs, either by allowing adjustment of the swing points, ie does it go on when the temp drops by .5 deg or 1 deg, etc., or by setting the number of cycles per hour. I have a Honeywell VisionPro and it uses the latter method. Since you're concerned about humidity, I'd get one that also controls that. Essentially, if you set it to say 75F and humidity is above a set point, it will run it anyway within limits, allowing temp to drop to say 73 or 74 to reduce humidity. I don't have that, Honeywell probably has ones that do. I've been very happy with the VP series that I've had. You can find them on Ebay. Also, if I was buying one today I'd get one that is internet connected. It's a nice feature where if you're coming home early, from a trip, etc you can fire it back up from your phone. Also, you can check while you're away, see what the temp is, etc.

Reply to
trader_4

I live in your area, FWIW. Cycling has a lot to do with your thermostat's "anticipator." I think I have mine maxed to avoid excessive cycling. Thermostat placement is also important, as is air circulation in your home. Unless it's in the 90's, mine cycles only enough to reach the temp the thermostat is set to. That doesn't mean it's the same temp everywhere in the house, just the hallway where the thermostat is mounted on the wall. It's important to have good air circulation to avoid hot spots. I have ceiling fans. I'll try to remember to time the cycling for you today. We should be close to the same temp.

Reply to
Vic Smith

Thank You Vic and trader_4 for your specificity. I am so upset about this s ituation, so helpful answers are appreciated. As a single female, I'm tired of getting screwed by contractors. The upsell of the 2.5 ton unit for my s mall place was where the problems started. It sounded like a jet was taking off in my living room every time the blower started. The humidity is so hi gh, I have to run the A/C until I'm freezing here at 68 or 69 degrees to ge t it down to 55%. Since I complained to the contractor right away, they rep laced the components outside with smaller ones, but I don't think that help ed. At this point I'm not sure what is reasonable to ask them to do. I beli eved them when they said "stuff happens" when the blower motor went out a c ouple of weeks ago when the thing was only 13 months old. Reading these thr eads and some articles, I'm finding out just how hard it is on certain comp onents like motors and such when its constantly starting from zero. Someone likened it to turning your car off at every stop light. So, I will no long er buy the "stuff happens" theory especially if someone can tell me my syst em is short cycling. Today it was in the lower 80s outside. I was trying to maintain a 74 degree temp. The A/C was on for 3-7 minutes and off for 7-12 minutes, most of the day. BTW, the thermostat is in a little hallway. No s unlight, drafts or vents. And also, the lower bills I was promised never ha ppened. My new, high efficiency system is not so efficient. Since the syste m is new, replacing it is not a cost-effective option. Maybe your advice re garding a thermostat that can "stretch" the cycle a bit could save on some wear and tear.

Reply to
patricialnemec

On Monday, September 18, 2017 at 12:24:30 AM UTC-4, snipped-for-privacy@gmail.com wr ote:

situation, so helpful answers are appreciated. As a single female, I'm tir ed of getting screwed by contractors. The upsell of the 2.5 ton unit for my small place was where the problems started. It sounded like a jet was taki ng off in my living room every time the blower started. The humidity is so high, I have to run the A/C until I'm freezing here at 68 or 69 degrees to get it down to 55%. Since I complained to the contractor right away, they r eplaced the components outside with smaller ones, but I don't think that he lped. At this point I'm not sure what is reasonable to ask them to do. I be lieved them when they said "stuff happens" when the blower motor went out a couple of weeks ago when the thing was only 13 months old. Reading these t hreads and some articles, I'm finding out just how hard it is on certain co mponents like motors and such when its constantly starting from zero. Someo ne likened it to turning your car off at every stop light. So, I will no lo nger buy the "stuff happens" theory especially if someone can tell me my sy stem is short cycling. Today it was in the lower 80s outside. I was trying to maintain a 74 degree temp. The A/C was on for 3-7 minutes and off for 7-

12 minutes, most of the day. BTW, the thermostat is in a little hallway. No sunlight, drafts or vents. And also, the lower bills I was promised never happened. My new, high efficiency system is not so efficient. Since the sys tem is new, replacing it is not a cost-effective option. Maybe your advice regarding a thermostat that can "stretch" the cycle a bit could save on som e wear and tear.

While it's true that short cycling puts more strain on the motors and isn't as efficient, it's not why your motor failed in just one year. It might m ake a difference of it lasting 15 years instead of 20 or something like tha t, but not failing in just a year. Was it a basic motor or the new fancy v ariable speed ECM type? The latter is more failure prone. I had the ECM f an on the outdoor condenser go on my theme after just 2 years. That's what you get in the quest for higher seers. I replaced it myself for $90 with a basic standard motor, which was available from many sources and fit. A ne w ECM one would have cost 3x or 4x that.

If you replace the thermostat and stop the short cycles, you may notice an improvement in energy use too. Download the install manuals for any new on es you're considering. I know on the Honeywell vision pro you can set the number of cycles per hour. They also have adaptive recovery, where after ha ving the thermostat set back, when you set the time for it to resume, you p ick the time and temp you want and it figures out how much earlier to start it to reach that temp at that time,based on history and current conditions .

Reply to
trader_4

On Sun 17 Sep 2017 10:27:43a, Vic Smith told us...

I've never checked the settings inside my thermostat as I've had no reason to. I have checked the temperature in every room except the kitchen (it has no vent and is closed off except for the doorway. OUr temperature variant is no more than 2 degrees amongst all the rooms. Our unit cycles about 3 times an hour. We live in central AZ. We do use ceiling fans to help average out the temperature, and we keep the thermostat set at 77? F.

Reply to
Wayne Boatwright

snip

Mine was cycling about 3 times an hour yesterday. It was 82 outside and it was set at 79. I was wrong about having an adjustable anticipator - that was my old thermostat. The Honeywell I have now has CPH (cycles per hour) and since I don't remember programming it, it's probably set to the default, which is 4 (every 15 minutes.) The thermostat must have anticipator logic (aka hysteresis) built in. They don't give such technical details in the user manual. From experience, it's about 1 degree F. Patricia can check the user manual for her thermostat. Should be able stop the short-cycling if the thermostat setting is causing it. That's all I know.

Reply to
Vic Smith

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