Homebrew HVAC systems are one of those projects that take such a big investment of time, effort and money that you’ve got to be a really dedicated (ideally home-owning) hacker with a wide variety of multidisciplinary skills to pull off an implementation that can work in reality. One such HVAC hacker is [Vadim Tkachenko] with his multi-zone Home Climate Control (HCC) project that we covered first back in 2007. We now have rare opportunity to look at the improvements fifteen years of part-time development can produce, when a project is used all day, all year round in their own home. At the start, things were simple, just opening and closing ventilators with none of those modern MQTT-driven cloud computing stuff.
The current implementation, called DZ (GitHub project link) has been rewritten using modern reactive programming techniques (which apparently is a good thing for an HVAC control system) with the HCC-core application running on anything UNIX, but fits nicely on the Raspberry Pi. Measurement data (temperature, humidity, etc.) can be taken from 1-wire devices as well as XBee modules, enabling wired and wireless sensing around the installation. The system can control various air management appliances, such as heaters, heat pumps and fans depending on the need for heating, cooling or ventilation. Don’t forget that often neglected third leg of HVAC, the ‘V’ part is critical for a healthy house. The remote control and monitoring is courtesy of an Android application (HCC-Remote) which allows users to visualise the current status and what the HCC is currently doing to keep the programmed climate in check.
Data are transported using the common MQTT protocol, allowing simple connectivity to any sensors or controllers that already exist in an installation, with HCC providing integrations for ESPHome as well as Home Assistant, so there are plenty of options for building a system around existing hardware. The project is fairly big (as you’d expect for this length of time) but [Vadim] would like to stress that they see a lot of re-inventing of the wheel on this subject, and a good look at HCC may save some people a lot of pain implementing a system without such a solid grounding.
If your needs are more basic, perhaps this simple ESP8266-based smart vent will suffice? And, if the control system is less of a problem, and you’re more interested in the actual physical implementation, why not check out this DIY Energy Recovery Ventilator (ERV) project?