Air Conditioner "Energy Saver" Mode

Factual Questions
1

I have an air conditioner for a midsized room (10000 BTU) with regular “cool” mode, “fan only” mode, and “energy saver” mode. My inclination would be to stick it on “energy saver” but it has rather annoying behavior.

** rolls dice —OK, General Questions it is, although it was a candidate for MPSIMS and Pit **

Can anyone here satisfy my curiosity about why it behaves this way?:

•It runs for awhile just as it would on “cool” mode, then kicks completely off. No fan no compressor no nothing. Thermostat is set for 74° F and it will do this (come to a halt) when ambient temp is several degrees higher, e.g., 82 °

• After an interval of being completely dormant like that, it will kick back on, compressor will engage, fan blows air, and it runs like that for 25 seconds or so then shuts back off again. The air coming out doesn’t get appreciably cold during that interval and the room certainly doesn’t get much coolth.

• When it is dormant, there’s no air movement and the room feels hot and stuffy, generally nudging me towards switching modes to “cool” or “fan” depending on ambient temp and how I feel at the time.

Does it sound to anyone like the “energy saver” function is working as intended and that, despite its surface-level peculiarity, there’s a method to its compressorial madness? Or is this thing SNAFU’d or badly engineered? Or do you think maybe there are Sooper Secret Settings I need to ferret out and modify to make “energy saver” work better, etc? Details: Frigidaire model FFTA1033Q1

User’s guide/manual available at link but the only advice on troubleshooting “Air conditioner turns on and off rapidly” suggests dirty air filter or very hot day, neither of which seem like likely explanations (I’ve only had this sucker since around this time last summer and it hasn’t been subjected to heavy use).

2

A quick goggle around found this:

I also found several other, less helpful, sites that said pretty much what you think - ESM sucks.

3

It should be turning off when it senses the temperature at 74 degrees. The area around the AC, and the AC itself will be colder than the air temperature measured somewhere else. Just set the AC temperature lower until you get the temperature in the room you want. I don’t bother with energy saver, I leave it on for a while until the room is good and cold, then I turn it off. Having an AC switch on and off by itself annoys me.

4

You could try a watt hour meter like this and measure the usage with ESM and without over a few days.

5

I’ve tried ESM in the past and found it to keep the room significantly warmer. Uncomfortably so. So I just keep my window units set for what I like while home, and set them for 10 degrees warmer when I leave. It’s the compressors running that cost the most, I’m fine with the fans moving the air around while I’m gone, as I have pets.

6

If the outside air temp is close to your set point then energy saving mode can save a little. But if the outside air is HOT then forget energy saving mode.

It is also harder to get proper moisture removal in ESM because the compressor may cycle more. It is like having a over sized AC unit for your home.

7

I’m running plain old “fan only” at the moment and it feels cooler than it did on “energy saver”. Unless “energy saver” is intended to use fewer kw than “fan only”, that makes no sense.

8

Yeah, this feature is as dumb as toast. My new Frigidaire window unit has it too (don’t know the model number). Worse, when you first turn the machine on, it automatically shifts into ESM mode, and you have to step through the other modes until you get to the last mode, which is the one that makes it act like a goddam air conditioner.

My last Frigidaire window unit had 99 fan speeds that you could only step through sequentially. This is MUCH worse than having just 2 speeds. It also randomly shifted between Fahrenheit and Celsius display modes, and these were not mentioned in the manual (perhaps it’s a magic mushroom control they set depending on where they sell it, and what went wrong is just the fact that it keeps randomly changing). And, if the power went off and came back on while the unit was running, it would change its setpoint to 60 F or, of course, 16 C.

What a stupid user interface design. Give me one warmer/colder knob and it would have been OK. Add a high/low speed knob and it would have been perfect. Instead they give me all this, and a remote control too. So, I guess, when it goes down to 60, I can set it back to normal from bed…

9

I have a Delonghi unit where ESM seems to work much better.

The fan stays on, it’s only the compressor that goes on and off. I have not noticed any difference in its ability to cool the room or to keep it cool with the ESM on.

10

While on the subject, I have another question. Besides the Cool and fan, my window unit also has a ‘dry’ setting. I have not tried that mode, bit I wonder what would be different in dry mode as compared to Cool, because isn’t it the cooling that takes out the moisture?

11

I remember being told that Energy Saving Mode means that the AC shuts itself off for a set amount of time (like, say, ten minutes) and then wakes itself up and turns on the fan long enough to sample the air in the room and decide whether it needs to run the compressor for a while or just go back to sleep for another ten minutes.

In standard mode, the fan runs all the time but the compressor kicks in as needed when the room temp gets to far above the target temp. If it’s really hot outside, this is a rather good strategy.

But if it’s not very hot outside, then the fan just runs all day which wastes energy.

But what if it’s just a little tiny bit hot outside and you only need to run the compressor a small fraction of the day? That’s where ES Mode is more efficient.

So, why not just turn off the fan and then leave it off until the thermostat goes up above a certain point? Because then you’re relying on the air right in front of the AC unit, not the air in the entire room, and that can give you false readings. So it kicks in the fan to sample the air for a few seconds every ten minutes, then decides whether the compressor is needed.

If your AC unit really is running the compressor right off the bat in ES Mode, then I’d say it’s not functioning correctly.

12

A regular air conditioner runs the fan all the time and cycles the compressor on and off. That’s normal mode for most air conditioners. That’s not ESM.

Cool mode does work as a dehumidifier. Dry mode runs the fan slower and cycles the compressor on and off more so that the air conditioner ends up drawing more water out of the air. So it’s basically cool mode optimized for dehumidifying.

13

Correct. It is one of those things that is designed to improve the stated energy efficiency. Whether or not it is useful in a particular situation depends on a number of factors, such as where any heat sources are located relative to the A/C unit, how tolerant the room occupants are to swings in temperature, etc.

Another efficiency thing is that A/C units no longer have simple drains. Water is designed to pool by the outside coil / fan. The idea is that the fan has a “slinger blade” which picks up the water and sprays it on the coils, helping cooling. In reality, at least in dirty environments, that just means that the crud in the pan gets deposited on the coils, clogging them, the bottom of the unit rusts, and the fins on the bottom of the outside coil decompose.