Heating, ventilation, and air-conditioning (HVAC) comprise the “engine” that drives the comfort systems in most structures. They directly consume the largest portion of energy in buildings—which makes them critically important from an environmental standpoint. Additionally, good indoor air quality, to a significant extent, depends on the ventilation they provide, while a problematic mechanical system can create and distribute indoor pollutants.
The first place to look to minimize the impact of a mechanical system isn’t the equipment, however; it’s the building’s design and construction. Careful, integrated design and optimal levels of insulation can minimize the need for supplemental heating, ventilation, or air conditioning. In situations where a central mechanical system is still necessary, an efficient building envelope can reduce the size of that system. A high-performance domestic water heater is fully capable of supplying heat to a very well-insulated house in most U.S. climates.