Smart plug for through-wall air conditioner
July 17, 2022 2:43 PM Subscribe
My apartment has a GE-branded through-wall air conditioner with mechanical switches. It plugs into a wall outlet and appears to be 220v with a different style plug than I'm used to. I would like to get a smart plug that I can use to turn it on and off remotely or, at minimum, put it on a timer or schedule. Apple HomeKit compatibility is a massive plus.
I know I'm not going to get control other than on/off, and that's fine, since we normally leave the "temperature" setting in one place and just turn it on Low Cool.
I have very little information about the A/C other than the brand, as I cannot find a model number anywhere on it, other than on the plug itself it says "E124162 SP-008." That corresponds to a 220v plug per an internet search, but does not seem to be specific to my A/C as the place I found it discussed was in reference to a window A/C unit. Here are some pictures of the unit and the plug. I just realized the filter was out for cleaning in those pics, so it looks a little different than normal.
I've got an Apple HomeKit setup here and would very much prefer to stay in that ecosystem if possible, but if the solution has a functional standalone app, I'm willing to consider it. E.g. if it requires setting up a Samsung SmartThings home or using Alexa, I'm not interested. I would very strongly prefer to be able to control it while not at the premises, so Bluetooth- or ad-hoc Wi-Fi-only options are heavily discouraged, but I'm willing to consider it if it's the only one you know of. I can't drill any holes or hardwire anything, but screws or nails are OK (not sure how that would even work, but just in case).
I thought about this previously and my internet searching came up with nothing so I forgot about it until somebody suggested in a recent Ask that the person get a "smart switch" for their through-wall A/C. All of the smart plugs I have been able to find are either only two prongs or limited to lesser voltage.
I know I'm not going to get control other than on/off, and that's fine, since we normally leave the "temperature" setting in one place and just turn it on Low Cool.
I have very little information about the A/C other than the brand, as I cannot find a model number anywhere on it, other than on the plug itself it says "E124162 SP-008." That corresponds to a 220v plug per an internet search, but does not seem to be specific to my A/C as the place I found it discussed was in reference to a window A/C unit. Here are some pictures of the unit and the plug. I just realized the filter was out for cleaning in those pics, so it looks a little different than normal.
I've got an Apple HomeKit setup here and would very much prefer to stay in that ecosystem if possible, but if the solution has a functional standalone app, I'm willing to consider it. E.g. if it requires setting up a Samsung SmartThings home or using Alexa, I'm not interested. I would very strongly prefer to be able to control it while not at the premises, so Bluetooth- or ad-hoc Wi-Fi-only options are heavily discouraged, but I'm willing to consider it if it's the only one you know of. I can't drill any holes or hardwire anything, but screws or nails are OK (not sure how that would even work, but just in case).
I thought about this previously and my internet searching came up with nothing so I forgot about it until somebody suggested in a recent Ask that the person get a "smart switch" for their through-wall A/C. All of the smart plugs I have been able to find are either only two prongs or limited to lesser voltage.
Another option would be to get an IR controller and setup HomeBridge to control it and make it available in HomeKit.
posted by Blue Jello Elf at 3:06 PM on July 17, 2022 [4 favorites]
posted by Blue Jello Elf at 3:06 PM on July 17, 2022 [4 favorites]
I was the one who suggested that, and most smaller window units are not going to be massively affected by being cut off that way, but I would be very reluctant to do it on one that was 220v.
posted by Lyn Never at 4:22 PM on July 17, 2022 [1 favorite]
posted by Lyn Never at 4:22 PM on July 17, 2022 [1 favorite]
Best answer: It's called a "NEMA 6-15”.
If you turn the thermostat all the way hot, and it turns off and you don't hear anything else running (besides gurgling) then you can safely turn it off with a 240V switch, so long as you wait at least a minute after turning it off before turning back on each time.
posted by flimflam at 4:24 PM on July 17, 2022 [1 favorite]
If you turn the thermostat all the way hot, and it turns off and you don't hear anything else running (besides gurgling) then you can safely turn it off with a 240V switch, so long as you wait at least a minute after turning it off before turning back on each time.
posted by flimflam at 4:24 PM on July 17, 2022 [1 favorite]
Not a great idea to turn your air conditioner off by cutting power.
The reason the interior fan keeps running is so the evaporator doesn't freeze up when the unit is cycling on and off every few minutes at a temperature setpoint. It's not a problem to turn it off twice a day with the mains power because it'll warm up.
posted by flimflam at 4:30 PM on July 17, 2022 [3 favorites]
The reason the interior fan keeps running is so the evaporator doesn't freeze up when the unit is cycling on and off every few minutes at a temperature setpoint. It's not a problem to turn it off twice a day with the mains power because it'll warm up.
posted by flimflam at 4:30 PM on July 17, 2022 [3 favorites]
No.
Smart plugs don't exist for high power appliances like this without extreme expense. And it's likely to destroy the a/c before controlling it for too long.
You are looking to solve this on the wrong way.
Temperature control? Figure out how to control the ac that way.
posted by TheAdamist at 6:08 PM on July 17, 2022 [1 favorite]
Smart plugs don't exist for high power appliances like this without extreme expense. And it's likely to destroy the a/c before controlling it for too long.
You are looking to solve this on the wrong way.
Temperature control? Figure out how to control the ac that way.
posted by TheAdamist at 6:08 PM on July 17, 2022 [1 favorite]
Best answer: Concur with everyone else. The heaviest smart plug I can easily find is 10A total. Most are rated for much less. Central air condition needs anywhere between 15-60 amps. You'll fry the switch or fry the AC unit itself.
You should look into a smart thermostat controlling the AC's settings instead probably through an IR bridge if your AC takes remote signals through IR.
posted by kschang at 8:43 PM on July 17, 2022 [2 favorites]
You should look into a smart thermostat controlling the AC's settings instead probably through an IR bridge if your AC takes remote signals through IR.
posted by kschang at 8:43 PM on July 17, 2022 [2 favorites]
Best answer: How handy are you? It looks like that particular unit has mechanical knobs and no electronic controls. If you told me to solve this as cheaply as possible with tools I have on hand, I'd probably use some 3d printed plastic bits to adapt some heavy-duty hobby servos to turn the knobs, and drive the whole thing with an ESP board that either hosts a little mini-website to control, or adapt to MQTT for Home Assistant. No idea if heavy RC/hobby servos could do the job, but it's where I'd go first, followed by stepper motors if I couldn't make that work..
posted by Alterscape at 10:20 PM on July 17, 2022 [2 favorites]
posted by Alterscape at 10:20 PM on July 17, 2022 [2 favorites]
Best answer: Are you or do you know anyone who is electrically handy? You could buy a 240v 30A 2 pole 120v coil DP contactor (EG); mount it in a 6x6x4 box; and then wire it to be controlled with a regular 110v smart switch. IE bring 2-3 conductor #12 SOOW cords about 2' long out of the box. One goes to the line side of the contactor and the other to the load. The line side cord gets a male cord end that matches your receptacle. The load side gets a cord end that matches your A/C. Additionally bring out a 3 conductor #14 SOOW cord. The internal end is hooked to the 120v coil of the contactor and the outside end gets a male 120v three prong cord end. This cable should be 6' long so it can reach your standard smart switch.
Plug the 240v cord into your a/c receptacle, the a/c into the other 240v cord and the third cord into a smart switch compatible with your system. The smart switch will control the dumb switch which will control the a/c.
This should not damage your A/C as long as you don't short cycle it. IE when you turn it off wait at least a couple minutes before turning it back on to allow the head pressure to bleed thru to the low side so the compressor doesn't attemp to start under a load.
Including the box, contactor, cables, cord ends, strain reliefs and Sta-kons (if required by your contactor) should run you around $100 or less plus the cost of the smart switch.
posted by Mitheral at 1:35 AM on July 18, 2022 [4 favorites]
Plug the 240v cord into your a/c receptacle, the a/c into the other 240v cord and the third cord into a smart switch compatible with your system. The smart switch will control the dumb switch which will control the a/c.
This should not damage your A/C as long as you don't short cycle it. IE when you turn it off wait at least a couple minutes before turning it back on to allow the head pressure to bleed thru to the low side so the compressor doesn't attemp to start under a load.
Including the box, contactor, cables, cord ends, strain reliefs and Sta-kons (if required by your contactor) should run you around $100 or less plus the cost of the smart switch.
posted by Mitheral at 1:35 AM on July 18, 2022 [4 favorites]
No idea if heavy RC/hobby servos could do the job,
A standard DC motor with a reduction gearbox and two microswitches to sense the desired "high" and "low" positions would do the job. But this too requires a good dose of tinkering.
posted by Stoneshop at 2:56 AM on July 18, 2022
A standard DC motor with a reduction gearbox and two microswitches to sense the desired "high" and "low" positions would do the job. But this too requires a good dose of tinkering.
posted by Stoneshop at 2:56 AM on July 18, 2022
kschang: You'll fry the switch or fry the AC unit itself.
Thatr's what relays are for, like Mitheral describes.
posted by Stoneshop at 3:42 AM on July 18, 2022
Thatr's what relays are for, like Mitheral describes.
posted by Stoneshop at 3:42 AM on July 18, 2022
Alternatively, buy a smart AC controller that will control your existing AC with remote and smartphone. It has a built-in IR Blaster that will emulate the remote. Automatically turns off AC when you leave the house due to geofencing, and turns it back on when you get back into range. Setup day and night schedules, and more.
posted by kschang at 9:40 AM on July 18, 2022
posted by kschang at 9:40 AM on July 18, 2022
OP's old school A/C is strictly mechanical, nothing for the IR blaster to blast to.
posted by Mitheral at 10:12 AM on July 18, 2022 [1 favorite]
posted by Mitheral at 10:12 AM on July 18, 2022 [1 favorite]
Best answer: I'm not sure I understand the point of the IR blaster/controller suggestions, given that the AC does not have the ability to be remote controlled in the first place. It's quite literally just a couple of mechanical knobs on the front to control temperature and fan speed, which you can see if you scroll down in the set of pictures linked by the OP.
I'd agree that a relay is technically the way to solve this, but 240v and DIY in the same sentence just makes me squirm. I'd agree with the answers that say no, there isn't a cheap or easy way to do this. Maybe some 240v equipment meant for European/UK systems could be adapted but again I don't think it'd be possible to do this with completely off-the-shelf components.
posted by Aleyn at 10:13 AM on July 18, 2022 [1 favorite]
I'd agree that a relay is technically the way to solve this, but 240v and DIY in the same sentence just makes me squirm. I'd agree with the answers that say no, there isn't a cheap or easy way to do this. Maybe some 240v equipment meant for European/UK systems could be adapted but again I don't think it'd be possible to do this with completely off-the-shelf components.
posted by Aleyn at 10:13 AM on July 18, 2022 [1 favorite]
Response by poster: Thanks for all the information, everyone!
As ssg surmised, I can't make any modifications to the A/C itself, and while there are a couple really interesting ideas about DIY projects that are external to it, I'm not handy in those ways and would not feel comfortable with making external electrical modifications, either. The unit doesn't have a remote; it's all operated from the knobs on the front, so an IR blaster/controller will not work, either. (On preview, Mitheral & Aleyn beat me to that point.) So I guess I'm stuck with what I have, which is annoying but at least I have an answer.
flimflam: If you turn the thermostat all the way hot, and it turns off and you don't hear anything else running (besides gurgling)
The fan is still running at that point, and runs 100% of the time that the control knob is not in the "Off" position. I just hear a click indicating the cooling has turned off when I turn the thermostat warmer.
There is one point I'm a little confused on. Turning the A/C off by cutting the power was specified as a Bad Thing, and that sort of makes sense to me...but what I don't understand is how that is different than using the knob to cut the power (e.g. going from Low Cool to Off), since in that case the whole unit, including the fan, turns off immediately. Or is that the same thing that flimflam was talking about in their second post?
flimflam: The reason the interior fan keeps running is so the evaporator doesn't freeze up when the unit is cycling on and off every few minutes at a temperature setpoint. It's not a problem to turn it off twice a day with the mains power because it'll warm up.
I'm not going to do that since there's no benefit if I'm already standing in front of it, just trying to understand this part.
posted by tubedogg at 10:22 AM on July 18, 2022
As ssg surmised, I can't make any modifications to the A/C itself, and while there are a couple really interesting ideas about DIY projects that are external to it, I'm not handy in those ways and would not feel comfortable with making external electrical modifications, either. The unit doesn't have a remote; it's all operated from the knobs on the front, so an IR blaster/controller will not work, either. (On preview, Mitheral & Aleyn beat me to that point.) So I guess I'm stuck with what I have, which is annoying but at least I have an answer.
flimflam: If you turn the thermostat all the way hot, and it turns off and you don't hear anything else running (besides gurgling)
The fan is still running at that point, and runs 100% of the time that the control knob is not in the "Off" position. I just hear a click indicating the cooling has turned off when I turn the thermostat warmer.
There is one point I'm a little confused on. Turning the A/C off by cutting the power was specified as a Bad Thing, and that sort of makes sense to me...but what I don't understand is how that is different than using the knob to cut the power (e.g. going from Low Cool to Off), since in that case the whole unit, including the fan, turns off immediately. Or is that the same thing that flimflam was talking about in their second post?
flimflam: The reason the interior fan keeps running is so the evaporator doesn't freeze up when the unit is cycling on and off every few minutes at a temperature setpoint. It's not a problem to turn it off twice a day with the mains power because it'll warm up.
I'm not going to do that since there's no benefit if I'm already standing in front of it, just trying to understand this part.
posted by tubedogg at 10:22 AM on July 18, 2022
Best answer: Your unit won't be damaged by cutting the power. In fact there uaed to be lots of thru the wall A/C and HVAC units in places like motels that were controlled by line voltage thermostats which is essentially the same thing. The thermostat or the unit sometimes had an on delay timer so that the compressor couldn't be short cycled but mostly not.
posted by Mitheral at 12:07 PM on July 18, 2022 [2 favorites]
posted by Mitheral at 12:07 PM on July 18, 2022 [2 favorites]
I'd agree that a relay is technically the way to solve this, but 240v and DIY in the same sentence just makes me squirm.
This European is totally comfortable with the combination of DIY and 230V (and even 3-phase 230V, so 400V between phases), but anyone else is free to squirm if they want to.
For both voltages you do need to know what you're doing, do everything according to code, and work neatly. 120V needs double the current for a same consumer wattage compared with 230/240V, and that too isn't tolerant of an inattentive job.
posted by Stoneshop at 5:39 AM on July 22, 2022
This European is totally comfortable with the combination of DIY and 230V (and even 3-phase 230V, so 400V between phases), but anyone else is free to squirm if they want to.
For both voltages you do need to know what you're doing, do everything according to code, and work neatly. 120V needs double the current for a same consumer wattage compared with 230/240V, and that too isn't tolerant of an inattentive job.
posted by Stoneshop at 5:39 AM on July 22, 2022
Or is that the same thing that flimflam was talking about in their second post?
Yes.
The thermostat may switch the compressor back on after just a short time, and because of that the fan needs to be kept running to let the cooling coils not freeze up in between.
If you switch off the unit by cutting the power externally, you can do so provided you leave it off for long enough that the cooling coils can warm up again by themselves; I'd estimate at least half an hour.
posted by Stoneshop at 5:50 AM on July 22, 2022
Yes.
The thermostat may switch the compressor back on after just a short time, and because of that the fan needs to be kept running to let the cooling coils not freeze up in between.
If you switch off the unit by cutting the power externally, you can do so provided you leave it off for long enough that the cooling coils can warm up again by themselves; I'd estimate at least half an hour.
posted by Stoneshop at 5:50 AM on July 22, 2022
This thread is closed to new comments.
If you want to control your air conditioner, you can do so by replacing the thermostat with a relay, but that's not going to be a plug and play solution and not something you want to do if you don't own the air conditioner, which it sounds like is the case here.
posted by ssg at 3:01 PM on July 17, 2022 [5 favorites]