HVAC systems are a gant leap up from window air conditioners and conventional radiators. But the first generation of HVAC can still suffer from temperature variation due to limited air flow outlets. High velocity HVAC, on the other hand, compensates for this and can cool and heat rooms evenly. Room air is drawn in to a high flow system requiring less energy to change temperature and high velocity systems also use flexible ducts, saving on space. Even homes previously unable to house HVAC systems easily due to architecture constraints, can incorporate high velocity HVAC.