I'll probably not need to change it, but I do have up/down buttons which I have included in the project. I have a five degree window. IE, when it turns on at 80, the relay will turn off at 85. The current version is only 4, because it turns on the relay at 80.9. I'll change it later to 79.9 by decreasing the thermostat setting in software. In other words, turn on the relay when the current temperature is at the thermostat setting minus one. In the program I'm only using whole numbers when comparing current temperature. and the thermostat setting.