Back in the days of cheap electricity and drafty homes, sizing an A/C was a quick and simple process. Your HVAC tech simply calculated the square footage, and added a half-ton or more for good measure. With higher energy prices, tighter homes and greater efficiency and comfort expectations of homeowners today, your HVAC technician should incorporate modern building science for correctly sizing a central A/C system. Here’s how:
Measuring a Home’s Load
When your HVAC technician is sizing a central A/C system, he or she is sizing the new A/C unit and the air ducts that convey cooled air to the home. The size of the new A/C is contingent upon the home’s cooling load. The size of the ductwork is contingent upon the size, or output, of the A/C unit.
Measuring a home’s load is a process that requires dozens of meticulous calculations and assessments of heat gain/loss, past energy bills, occupant numbers, energy usage habits, insulation values and much more. If there are mistakes in the load calculation, the A/C will be the wrong size. That’s a mistake you can’t afford to make.
Selecting the Right-Sized A/C
With load calculations in hand, you’re ready to choose the right A/C for your needs. Ask your HVAC technician to provide you a lifetime cost analysis of different A/C models you’re considering for your home. The lifetime costs of an A/C system is the sum of purchase, installation, estimated operating expenses and estimated repairs for the lifetime of the new A/C. This is your true investment—not just the sticker price, or first cost.
Duct Design
Older existing ductwork may need repairs or modification to accommodate the new A/C and blower. Ducts undergo substantial static pressure, and leaks or damage occur over time. Like calculating a home’s load, HVAC-industry best practices for building science should be used for duct design and sizing. If your ducts are modified or retrofitted, make sure they’re leak-tested before final approval.
For more information about sizing a central A/C system for your Lorain home, contact the experts at Energy 1 Heating & Air Conditioning for the answers.
Our goal is to help educate our customers in Lorain, Ohio about energy and home comfort issues (specific to HVAC systems). For more information about A/C systems and other HVAC topics, download our free Home Comfort Resource guide.
Credit/Copyright Attribution: “Yuliyan-Velchev/Shutterstock”
Energy 1 Heating & Air Conditioning
1 (440) 246-5440
Serving the Lorain, OH Area