Are HVAC Load Calculations Necessary For System Efficiency?

Performing load calculations is one of the most important steps in installing a new HVAC system. If not done correctly, the performance and efficiency of the whole system suffers. Before you have a new system installed in your West Chester, PA area home, learn a little about load calculation so you’ll know what to expect.

Estimates aren’t enough

In the past, contractors often estimated loads based on the home’s square footage or they sized a new system based on the old system. Because today’s homes are more energy efficient, though, their heating and cooling loads are smaller, so they require smaller HVAC systems. For accurate load calculations, responsible contractors follow Manual J, a method developed by the Air Conditioning Contractors of America (ACCA).

Fundamentals matter

When calculating your home’s loads, your contractor should take into account design issues such as your home’s size and orientation, thermal enclosure issues such as your home’s insulation and airtightness, and the internal loads created by the residents, appliances and other heat sources. Manual J covers these issues. The sizing, layout, and other factors of your duct design also affect the loads.

For these issues, contractors follow the ACCA’s Manual D. Start with complete information

If you expect accurate load calculations, provide your contractor with the plans for your house and all necessary specifications. If you can’t, the contractor should inspect your home to obtain the necessary information. Performing the calculations without sufficient information may save time, but it’s likely to leave you with an incorrectly sized system.

Avoid oversizing

An oversized system can perform well in more extreme weather, but in average weather it just wastes energy, places undue wear on the components, and can’t control humidity well. Some contractors calculate loads based on worst-case scenarios and oversize systems, but this isn’t necessary. Your HVAC contractor should size your system based on realistic data.

For more professional guidance on HVAC system upgrades and other home comfort issues, contact us at Sobieski Services. Our goal is to help educate our customers who live near Delaware, Pennsylvania, Maryland and New Jersey about energy and home comfort issues (specific to HVAC and plumbing systems).

Image Credit: Skakerman