Hi all! I'm new to Arduino. I have 2 offices(4 classrooms each) in different places. I would like to build a system that can be managed from web and can connect to SQL Server. The goal is: Arduino connects to SQL server, takes class schedule and half an hour before class turn on ventilation (Lossnay) and air conditioner. Not only turn on, but give to conditioner a command to certain temperature (for example 23 grad). Also there will be CO2 sensors to give commands to HVAC system(Lossnay). Right now I'm choosing ventilation system and air conditioning system(possible multisplit with 4 internal cassetes). I would like your advice in choosing this systems. 1. Which ones is better to manage from Arduino? Mitsubishi, electrolux or others. 2. Is there are HVAC systems to which I can connect Arduino without IR Remote? Directly connect cables.