In an ideal world, passive design systems would be enough to heat, cool and ventilate whole cities. But we don’t live in a perfect world, which means there will be times when passive energy systems won’t be enough. In those moments, you’ll need mechanical Heating, Ventilation, and Air Conditioning (HVAC) systems to help keep building occupants comfortable. The problem today is that HVAC systems are usually designed by mechanical engineers and typically account for 30% or more of a building's total energy use. To achieve net zero energy buildings, you’ll need an effective HVAC strategy. So, without further ado, here are three simple rules to keep in mind when designing for mechanical HVAC systems: 1. Don't oversize the system 2. Choose efficient components 3. Design passive and mechanical systems to work together More information from the Autodesk Sustainability Workshop Efficient HVAC Design http://sustainabilityworkshop.autodesk.com/strategy/efficient-hvac-design Go to the original post...