On average, heating and cooling account for half of a home’s energy usage. Because heating and cooling are such a large percentage, it’s important to make sure the system is engineered for efficiency. Maximizing the efficiency is the most cost-effective way of keeping a home comfortable. However, even the most energy-efficient heating and cooling system will fail to save homeowners money if it’s poorly installed. The following are three general guidelines to help ensure optimum HVAC performance.
Size it right
When it comes to HVAC equipment, bigger isn’t necessarily better. For example, if a central air conditioner is oversized, it will run for short, vigorous cycles, creating spikes in temperature. The system won't run long enough to remove moisture from the air, so homeowners will feel hotter, because the air is more humid. An oversized system wastes energy instead of providing more cooling. Instead, if the system is sized properly for the home, it will run for longer intervals, helping to mix the air and maintain a more uniform temperature. Think of a car that gets better gas mileage when coasting at a steady 55 miles per hour than straining in stop-and-go traffic. To run efficiently, the size of the system should be compatible with the heating and cooling loads.
Tip: Choose air conditioners that have a higher seasonal efficiency rating (SEER). The higher the rating, the more efficient the air conditioner will be, helping homeowners save money on cooling costs. In fact, ENERGY STAR qualified air conditioners can potentially cut cooling costs by 30%.
Seal and insulate the rest of the home
An oversized HVAC system can’t compensate for building flaws, such as uncontrolled air leakage, improperly installed or missing insulation, and minimum efficiency windows. A properly sized and installed HVAC system is basically worthless if a home has these issues; it has to work harder to keep the home at a comfortable temperature.
Make sure a home has continuous insulation and is air sealed properly using expanding foam, caulk, and weatherstripping. A properly installed thermal enclosure plays a key role not only in reducing energy consumption, but also in alleviating customer comfort complaints resulting from drafts or uneven temperatures.
Get air where it’s needed
The heating and cooling system is effective only if the air it heats and cools gets to the spaces where the homeowners are. In a forced-air system, a well-designed combination of ductwork and supply registers delivers the right quantity of air and mixes it well with the room air, without creating drafts. Before beginning installation, the HVAC contractor has to accurately calculate the home's load according to the Air Conditioning Contractors of America's (ACCA) Manual J, select mechanical equipment according to Manual S, and size ductwork according to Manual D. All ductwork should be installed in the conditioned space and sealed properly with UL 181 approved mastic.
When you size the system properly, reduce heat transfer through the thermal enclosure, and build a system that delivers air appropriately, you create an HVAC system that provides comfort and lowers heating and cooling bills. Now that lightens the load on homeowners. To learn more about HVAC systems, check out BuildIQ University's online training course, Mechanicals: HVAC.
