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A DIY controller built for two split air conditioners cost its author $169.70, including shipping, and was estimated to avoid about 450 kWh of electricity use per month by switching the units off overnight. That 450 kWh figure is not a meter reading: Givi Pataridze says he installed no electricity meter, so it is an estimate based on assumed AC power draw, compressor duty cycle, and shutdown time.
What the $169.70 controller does
In a September 24, 2026 account, Givi Pataridze describes building a controller for two wall-mounted split AC units in a small photo studio. The studio was sometimes left cooling overnight while unattended, and bookings could begin with the room at an unsuitable temperature. The controller sends infrared commands to the indoor units and uses a separate room sensor to decide when to start or stop them.
The reported $169.70 total includes shipping and reflects the author’s historical component prices, not current quotations.
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Clear out junk files and repair common Windows errorsFree Scan →Scan for outdated or missing drivers - takes under a minuteDriver Scan →| Part | Reported cost | Role in the build |
|---|---|---|
| M5Stack Basic v2.7 with screen | $39.90 | Controller and local display |
| LAN PoE Base W5500 v1.2 | $48.50 | Base and power connection |
| Unit CO2L with SCD41 | $45.90 | Room sensor, including direct CO2 sensing |
| Two Unit IR emitters | $7.90 each | Send commands to the two ACs |
| Grove cables and jumpers | $10.40 | Wiring |
The author reports that the PoE base supplied power in the final build, but not network data; the controller used Wi-Fi for data. Four jumper wires had to be soldered between internal pads and the base’s screw terminals for ground, 5V, and the two IR signal lines. Pataridze says those terminals were not connected from the factory.
#1 Best Overall
- Control Your AC From Anywhere: Cielo Breez Lite makes any ductless air conditioner or heat pump smart. Use the free iOS or Android app to control your AC from anywhere, anytime. NO monthly subscriptions.
- Super Easy Set-Up: Cielo Breez Lite is compatible with 20,000+ ductless mini-split, window, or portable AC and heat pump models. It automatically detects your remote control and is super easy to configure. It just takes a minute to set up. No tools required. For optimal placement and control, place Breez Lite within 6-12 feet and in the line of sight of your air conditioner.
- More Options, Better Control: Talk to your air conditioner using Google Assistant, Amazon Alexa, and Siri shortcuts. Cielo Breez Lite is also compatible with SmartThings and IFTTT!
- Enhanced Comfort & Savings: Designed to prioritize energy savings without compromising your comfort. Cielo Breez Lite smart air conditioner controller is loaded with next-gen features to help you save on heating and cooling bills.
- Perfect Temperature Always: Built-in temperature and humidity sensors, in combination with smart features, ensure perfect room temperature. You can always set intelligent triggers for an automated home climate.
How the room-temperature control works
A room sensor—not the AC’s built-in thermostat—drives the control logic. The sensor updates every 60 seconds, according to the account. The controller sends an AC target temperature intended to keep the unit running until the separate room sensor reaches its cutoff.
| Mode | AC command while active | Start condition | Stop condition |
|---|---|---|---|
| Cooling | Set target to 18°C | Room reaches 24°C | Room reaches 23°C |
| Heating | Set target to 24°C | Room reaches 18°C | Room reaches 22°C |
The author says local logic continues without a server, cloud service, or phone app. The IR emitters are described as having a narrow beam and a range of roughly two meters. Pataridze also says the build required decoding an AC protocol that was not previously supported, after which the controller operated the indoor unit.
Rank #2
- Product Usage Instructions: Breez Max connects to a 2.4 GHz Wi-Fi network. It is compatible with any mini-split, window or portable unit that has an IR remote control. If your device doesn't work out of the box, please contact Cielo Customer Support to make it compatible. Breez Max has built-in temperature & humidity sensors that can be calibrated using the app. If the touch buttons don’t respond, press the temperature up & down buttons simultaneously to unlock the touch controls. For optimal placement and control, place Breez Max within 6-12 feet and in the line of sight of your air conditioner.
- AHR Product of the Year Smart Thermostat for Room Air Conditioners: Make your mini-split, window, or portable air conditioners smart (that come with an IR remote). Control your AC from anywhere using your phone or like a thermostat using on-device buttons with the award-winning smart thermostat for mini-splits.
- DIY Easy Set-Up: With an auto-detection algorithm for universal compatibility, Cielo Breez Max digital thermostat for mini-split can detect any air conditioner brand and model automatically! The smart air conditioner controller is compatible with over 20,000 models of mini-splits, window, or portable units.
- Comfy Max: With the AI-based Comfy Max ensure your AC only runs when it needs to, preventing overcooling and overheating. With a true thermostat like experience, always keep your home comfy and guarantee energy savings.
- Weekly Scheduling & Presets: Set one-time or repeat schedules for your air conditioner based on your routine. Your schedules will continue running smoothly even if internet connectivity is lost. Enjoy a truly tailored experience with predefined comfort settings including Home, Away, and Sleep.
Where the 450 kWh monthly estimate comes from
The estimate depends on assumptions rather than measured consumption. Pataridze says the AC remote model indicates 18,000-BTU-class units and assumes each draws roughly 1.5–1.8 kW while its compressor is running, with a 50% compressor duty cycle. For two units shut down for 9.5 hours each night, the article calculates about 15 kWh avoided per night, or roughly 450 kWh over a month. It gives a rough range of 350–570 kWh per month.
The Tool Desk
Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →As Pataridze puts it, “I did not install an electricity meter, so what follows is arithmetic on stated assumptions, not a measurement.” Actual savings could differ substantially if a particular AC draws more or less power, cycles at a different duty rate, runs for a different number of hours, or is not otherwise left on overnight. The estimate should not be treated as a result that automatically applies to another home, studio, or AC model.
Rank #3
- Control Your AC From Anywhere: Cielo Breez Lite makes any ductless air conditioner or heat pump smart. Use the free iOS or Android app to control your AC from anywhere, anytime. NO monthly subscriptions.
- Super Easy Set-Up: Cielo Breez Lite is compatible with 20,000+ ductless mini-split, window, or portable AC and heat pump models. It automatically detects your remote control and is super easy to configure. It just takes a minute to set up. No tools required. For optimal placement and control, place Breez Lite within 6-12 feet and in the line of sight of your air conditioner.
- More Options, Better Control: Talk to your air conditioner using Google Assistant, Amazon Alexa, and Siri shortcuts. Cielo Breez Lite is also compatible with SmartThings and IFTTT!
- Enhanced Comfort & Savings: Designed to prioritize energy savings without compromising your comfort. Cielo Breez Lite smart air conditioner controller is loaded with next-gen features to help you save on heating and cooling bills.
- Perfect Temperature Always: Built-in temperature and humidity sensors, in combination with smart features, ensure perfect room temperature. You can always set intelligent triggers for an automated home climate.
What the estimate means in dollars
At the article’s illustrative electricity rate of $0.10 per kWh, 450 kWh corresponds to about $45 per month in estimated savings. The author therefore suggests a payback of around four months for the reported $169.70 build under those assumptions. This is illustrative arithmetic, not a guaranteed return: the actual tariff and measured savings determine the payback.
Cheaper alternatives proposed by the author
Pataridze also outlines two lower-cost approaches. These are proposed alternatives in the article, not controlled or independently tested comparisons, and the stated costs are not current market quotes.
Rank #4
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| Approach | Approximate cost in the account | Wiring and control | Display and sensing | AC coverage |
|---|---|---|---|---|
| Featured M5Stack build | $169.70 including shipping; author’s reported historical total | Required soldered jumpers; PoE delivered power, while data used Wi-Fi | Screen and SCD41-based CO2 sensor | Two AC units, with two IR emitters |
| Two Atom Lite boards | Roughly $50; author’s proposed cost, not a current quote | Proposed no-solder route using USB phone chargers and Wi-Fi | Numbers viewed through ESPHome’s web page; SCD40 CO2 sensor on one board | Two boards, one near each AC |
| Generic ESP32 build | Roughly $20; author’s proposed cost, not a current quote | Requires soldering an IR LED, transistor, and resistors | Basic temperature and humidity sensor; no measured CO2 reading | Not stated in the article |
The Atom Lite proposal uses the board’s onboard IR LED, according to Pataridze. The generic ESP32 option is cheaper and omits CO2 sensing. An eCO2 value inferred from other gases is not the same as a direct CO2 measurement; the author names the SCD40 and SCD41 as photoacoustic or NDIR sensor examples. Current compatibility and availability for any of these parts are not established in the account.
Recommended Free Tools
The practical choice depends on whether the screen and physical controls, soldering work, power arrangement, number of ACs, or direct CO2 measurement matter for your setup. Pataridze writes, “I would build the $50 version today.”
Best Value
- Product Usage Instructions: Breez Max connects to a 2.4 GHz Wi-Fi network. It is compatible with any mini-split, window or portable unit that has an IR remote control. If your device doesn't work out of the box, please contact Cielo Customer Support to make it compatible. Breez Max has built-in temperature & humidity sensors that can be calibrated using the app. If the touch buttons don’t respond, press the temperature up & down buttons simultaneously to unlock the touch controls. For optimal placement and control, place Breez Max within 6-12 feet and in the line of sight of your air conditioner.
- AHR Product of the Year Smart Thermostat for Room Air Conditioners: Make your mini-split, window, or portable air conditioners smart (that come with an IR remote). Control your AC from anywhere using your phone or like a thermostat using on-device buttons with the award-winning smart thermostat for mini-splits.
- DIY Easy Set-Up: With an auto-detection algorithm for universal compatibility, Cielo Breez Max digital thermostat for mini split can detect any air conditioner brand and model automatically! The smart air conditioner controller is compatible with over 20,000 models of mini-splits, window, or portable units.
- Comfy Max: With the AI-based Comfy Max ensure your AC only runs when it needs to, preventing overcooling and overheating. With a true thermostat like experience, always keep your home comfy and guarantee energy savings.
- Weekly Scheduling & Presets: Set one-time or repeat schedules for your air conditioner based on your routine. Your schedules will continue running smoothly even if internet connectivity is lost. Enjoy a truly tailored experience with predefined comfort settings including Home, Away, and Sleep.
What to check before building a similar controller
- Confirm the AC accepts IR commands. The described design depends on sending compatible commands to the indoor unit; the account involved decoding a protocol that was not already supported.
- Plan for wiring, not just the parts list. The featured build needed four soldered jumper connections because the base’s screw terminals were not preconnected to the required signals.
- Place the IR emitter within range and aim it correctly. The author reports a narrow beam and roughly two-meter range, so placement matters.
- Use your own consumption inputs for a savings estimate. AC draw, compressor cycling, nightly schedule, and local electricity rate all affect the result.
- Choose the sensor for what you want to measure. A temperature sensor can support the control logic; a direct CO2 sensor adds a separate measurement that an eCO2 estimate does not provide.
Source and evidence limits
The component list, operating details, and savings arithmetic above come from Givi Pataridze’s September 24, 2026 account, “A $169 DIY AC controller that saves 450 kWh a month”. A DEV Community republication carries the same article and is not independent confirmation. The account provides no electricity-meter data or controlled comparison of the proposed alternatives.
Quick Recap
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