What is the definition of a programmable HVAC controller? This question is often asked by people who are looking to upgrade their current HVAC system. A programmable HVAC controller is a device that allows you to control the temperature of your home or business. It works by connecting to your existing HVAC system and allowing you to control the temperature settings from a remote device such as a smartphone or computer. You can set up a programmable HVAC controller to adjust the temperature automatically throughout the day based on the time of day and your preferences. This can be beneficial if you have a busy schedule and don’t want to manually adjust the temperature throughout the day. It can also help with energy efficiency as you can minimize energy use during the times when you’re not home or don’t need the temperature to be kept at a certain level. Programmable HVAC controllers are designed to save you time, energy, and money. They are becoming increasingly popular as a way