Checklist: HVAC
A home can be heated or cooled using electricity, gas, geothermal energy, solar energy or a combination of energy sources. Radiant-floor heating systems are an inherently efficient way to heat, since there is no heat lost through ductwork, but a forced-air heating system can also be a very efficient option if designed and installed properly. The items on this checklist should be considered when installing any type of ducted system.
First off, a room-by-room J heat-loss/heat-gain calculation must be completed. Maximum-oversizing limit for air conditioners and heat pumps is 15 percent. Adhering to the maximum-oversizing limit both ensures that you are not paying for more capacity than you need and that the system will properly dehumidify the home and run efficiently.
• Heat pumps and air conditioners must have a Seasonal Energy Efficiency Ratio rating of at least 14 SEER and a Heating Season Performance Factor of at least 7. Gas furnaces used for either primary heat or backup heat should have a rating of at least 90 Annual Fuel Utilization Efficiency.
• Locate ductwork and the mechanical unit in the conditioned space, if possible. All ductwork should have an insulating value of R-8.
• Consider using rigid metal ductwork for increased durability and indoor-air quality. Rigid metal is easy to clean, and will not trap dust or absorb moisture.
• Building cavities, such as floor joists, should not be used as part of the forced-air supply or return system.
• All joints/seams in the air-distribution system should be sealed with duct mastic and fiberglass mesh; this includes duct connection to metal boots (in subfloor), trunk lines and air-handler units. Insulating liner of ducts must also be sealed with mastic.
• Indoor- and outdoor-HVAC units must be matched according to the Air-Conditioning & Refrigeration Institute Directory or the manufacturer’s listing.
• Verify that the correct charge of refrigerant has been installed per the manufacturer’s specifications.
• Registers and diffusers must have proper throw and spread to keep rooms properly conditioned.
• Duct dampers should be installed and accessible on supply vents. The dampers make it possible to adjust the flow and spread of air from the registers.
• Ducts should be sealed and tested by a Home Energy Rater to have no more than 5 percent leakage.
• If you are installing a heat pump, make sure to install an outdoor thermostat to control when the electric heat strip’s power is on. This will maximize your efficiency.
• Install a programmable thermostat.
Sources for this checklist included Advanced Energy System Vision Guidelines, Southface Energy Institute Technical Bulletins, HealthyBuilt Homes program guidelines and Energy Star guidelines for homes and indoor quality.