Efficiency Elements

Heat Pumps

• Heat pumps can move thermal energy from cold materials to warmer

  materials

• This is the opposite direction from conduction

• Mosts thermal energy in buildings is released through combustion

• It can be more efficient to move thermal energy from outside the house

  to inside the house

Insulation

• Insulation slows the movement of thermal energy

• We may wish to trap thermal energy inside a building in a cold climate

• In summer, you want to prevent thermal energy from entering a building

Ventilation

• Buildings must provide a certain level of fresh air to support human

  health

• In a cold climate, this means bringing in cold air from the outside

• This cold air must be heated, requiring energy

• Air to air heat exchangers can use the outgoing warm air to preheat

  the incoming air, reducing the heating load

Monitoring

• Buildings often use more energy than their designers intended

• An important efficiency tool is the monitoring of a building for

  energy use

• By comparing energy use between similar days, we can look for changes

  in performance because of technical or behavioral causes.

• Similar days can mean temperature, number of occupants, or other

  factors