HVAC stands for heating, ventilation and air conditioning. These systems make built environments suitable for extended occupancy, and they are covered by HVAC engineering, which is a subfield of mechanical engineering.
Well-designed HVAC systems are fundamental in any building project, since they ensure a suitable temperature and a constant supply of fresh air for indoor locations. Also consider that HVAC systems have a high operating cost, so they must be designed as efficient as possible. In residential and commercial settings, HVAC systems consume more energy than all other equipment combined, and they are only surpassed by heavy industrial processes.
HVAC systems typically use multiple fuel inputs. Normally, air conditioning and ventilation only use electricity, but space heating systems use a combination of electricity and fossil fuels. Natural gas is the most common heat source for space heating and domestic hot water, but many installations use other fuels such as propane and heating oil. You can also have fully electric heating systems, but their running cost can be excessive if they are based on resistance – only energy-efficient heat pumps can match the running cost of gas-based heating.
The best recommendation for HVAC systems is to use the right capacity, but there are ways to improve performance further. You can ask HVAC engineers to suggest equipment with a high energy efficiency rating, complemented with control systems to optimize their operation.
Energy efficiency ratings change depending on the specific type of HVAC equipment, but there is a common denominator: higher efficiency costs more, but long-term savings outweigh the additional cost. Energy ratings are calculated differently for each type of equipment, but a higher value always leads to a lower operating cost.
- Split-type air conditioners have the Seasonal Energy Efficiency Ratio (SEER)
- Furnaces and boilers have the Annual Fuel Utilization Efficiency (AFUE)
- Heat pumps have the Heating Seasonal Performance Factor (HSFP)
- Water heaters have the Energy Factor (EF).
HVAC performance can be improved further by using equipment controls. For example, the ventilation system can be ramped down when a building is not at full occupancy, and motor-driven equipment such as pumps and fans can be equipped with variable frequency drives (VFD) for speed control. A professional HVAC engineering firm can identify and suggest the most promising enhancements for your heating, ventilation and air conditioning equipment.