The fundamental purpose of an HVAC (Heating, Ventilation and Air Conditioning) unit is to keep the indoor air at optimal temperatures year round for the building’s occupants.
In order to accomplish this, the system can represent over 50% of a monthly electric or gas bill. Marking the HVAC system for leaving a high energy footprint, especially in climate zones that have a demand for constant usage. For this reason, energy efficient measures that focus on a smart HVAC design can achieve synergy and significant savings.
With the complex configurations of an HVAC system, in order to achieve maximum efficiency, it is always recommended to have a professional assessment by a mechanical engineering firm before beginning any HVAC upgrades.
HVAC Systems Energy Consumption
The energy source is the main distinction between HVAC systems. While electricity is the main source for the air conditioning and ventilation components, an array of energy sources – electricity, natural gas, and fuel oil – supply the heating systems.
For maximum energy efficiency from an HVAC system, several factors are taken into consideration in the architectural design. An ideal system configuration will prioritise ways to naturally minimise the summer heat gain and winter heat loss.
This is often accomplished by designing a building that is air-tight, installing adequate insulation, placing low-emissions triple-pane windows to capture the sun’s rays in the wintertime and using shades to prevent summertime overheating. Therefore, reducing the HVAC system workload and saving money on energy expenses.
HVAC Energy Efficient Measures
With a wide range of choices to consider when researching a new HVAC system and the uniqueness of every building, it is important to understand a few basic metrics of the system’s components.
To improve the energy efficiency of any HVAC system installation, there are two complementary concepts – upgrading the system’s equipment and key components, while upgrading to automatic controls for more efficient use.
Each component has a governmental energy efficiency rating score. The following list comprises the main HVAC system’s component and the name of the metric score which it is graded that if upgraded with newer efficient equipment will help lower monthly energy bills.
- Combustion-based boilers and furnaces – The Annual Fuel Utilisation Efficiency (AFUE)
- Commercial and Industrial Chillers – The Integrated Energy Efficiency Ratio (IEER)
- Air-Source Heat Pumps – Heating Seasonal Performance Factor (HSPF)
- Air Conditioning Units – Seasonal Energy Efficiency Ratio (SEER)
- Electric Motors – Electronically Commutated Motors (ECM)
The second part of our complementary components is integrating automatic controls to help lower the operating cost by keeping the HVAC system’s motor speed controlled in accordance to the current workload.
Another consideration is the importance of purchasing and installing the appropriate size of the HVAC to fit the building. If the system is too small, it will be constantly under a strain to sufficiently keep the building at a comfortable level. On the other hand, if the system is too large for the building it will be more expensive to install, operate and maintain.
Michael Tobias, PE, is the founder and principal of Chicago Engineers, an Inc 5000 Fastest Growing Company in America. Michael graduated from Georgia Tech in 2004 with honorary mentions. Michael and his team of 30+ engineers specialise in mechanical, electrical, and plumbing (MEP) engineering services in Chicago and New York.