Arduino Thermostat Projects

Control heating and cooling in your home with these Arduino projects

woman adjusting digital thermostat

 Peter Dazeley/The Image Bank/Getty Images

Home heating, ventilation, and air conditioning (HVAC) systems have been a household technology that the average homeowner doesn't typically know a lot about. The equipment for managing these systems has been the domain of specialists and a few companies. Even thermostats have not been simple to change or control.

But new technologies have made this area of home ownership more transparent to the average consumer, and the popularity of technologies like the Nest learning thermostat has demonstrated that there is demand for better interfaces and greater control over these aspects of the home. Tech enthusiasts can now use Arduino to develop their own custom hardware for controlling the temperature in the home and in other areas of home life.


Arduino is an open-source hardware and software system that consists of an easily programmable circuit board, known as a microcontroller, and software that runs on a computer. Arduino allows users to create devices that can sense and interact with its environment both physically and digitally.

Check out these Arduino-based thermostat project for some ideas of how Arduino can be used in to create your very own custom thermostat.

Project: a simple DIY thermostat project

This do-it-yourself thermostat project is one of the simpler Arduino-based thermostat solutions that would be appropriate for a beginner. It uses a Dallas DS18B20 one-wire temperature sensor, and a simple LED and LCD combo to indicate temperatures and the thermostat status. A relay shield provides the outputs that interface with the home HVAC system. If you are not looking to add any network features or sophisticated functionality to your Arduino thermostat, this project illustrates the basic layout of a thermostat project.

Project: a network-enabled thermostat

For a more complex look at the possibilities of an Arduino based thermostat, this project has a number of versions of a network linked thermostat for interfacing with HVAC systems. Over time, this project has become increasingly complex, with additional features like a complex multicolor display with a temperature and humidity sensor.

Project: a fridge controller

Home HVAC systems aren't the only areas in which a thermostat is required. Refrigerators are also typically controlled using a thermostat. If your refrigerator is causing problems due to a faulty thermostat, this Arduino refrigerator project might provide a solution. This project uses the same Dallas temperature sensor seen in the simple thermostat project, providing control for the compressor on the refrigerator. The project starts simply, and later updates provide the addition of an ethernet shield for logging the temperature and compressor state.

Project: a web-accessible thermometer

Perhaps you aren't looking to replace an entire thermostat system with a homebrew Arduino solution, but you would like to create a thermometer that is accessible on the web. This might be useful for a number of different applications, both around the home and potentially to monitor work environments like server rooms. The project creates a web-accessible thermometer, and the accompanying code uses a simple website and mobile app to create a messaging interface between the user and the thermometer device.

New possibilities for the casual tinkerer

These projects should provide an idea of how Arduino can be a great entry point to what was once a largely inaccessible part of home control available to the everyday tinkerer. Arduino has great potential to be a way to open up programming possibilities for everyday objects.

If you are interested in other options for Arduino development, look into ideas like Arduino motion sensor projects or Arduino lock devices.