Retrofitting

Outside air puts a great burden on the HVAC system. First, it’s usually hotter (colder) than the air returned from the conditioned spaces, so it must be cooled (heated) to the supply-air temperature. Second, it’s […]

The thermostat is the remote-control device for all the space-conditioning equipment. It’s a convenient means to monitor the space temperature and to control the equipment to use less energy while maintaining a comfortable environment. It’s […]

The operating principles of through-the-wall units, heat pumps, and other small self-contained air-conditioning systems are alike enough that some common remedial measures will help to keep them in peak working order: 1. Keep the evaporator […]

Energy-conscious designers cringe at a facility with all-electric heating. Electric strip-heating is the most inefficient and costly way to warm a space. Use of natural gas or oil to fire a boiler on the premises […]

A favorite — but wasteful — means to control the direct-expansion loop is with a hot-gas bypass valve. A thermal-expansion valve maintains a constant temperature of the fluid in the discharge line. As a result, […]