The following animations are good videos showing animations of how heat engines and heat pumps work. The Otto Cycle and internal combustion engines. The Diesel engine. A split-system air-source heat pump.

The second laws of thermodynamics states that heat spontaneously flows from bodies at higher temperature to bodies at lower temperature. Thus, it is an inevitable outcome of all systems left to their own devices to eventually reach thermal equilibrium. The purpose of insulation is to reduce the speed at which equilibrium is reached. Insulation reduces

HSPF stands for Heating Seasonal Performance Factor. It is a measure defined by the Air Conditioning, Heating, and Refrigeration Institute to rate the heating efficiency of air conditioner or heat pump. Let me emphasis that again, the HSFP rating only reflects the heating efficiency of a heat pump, not its cooling efficiency. Cooling efficiency is

SEER stands for Seasonal Energy Efficiency Ratio. It is a measure defined by the Air Conditioning, Heating, and Refrigeration Institute to rate the cooling efficiency of air conditioner or heat pump. Let me emphasis that again, the SEER rating only reflects the cooling efficiency of a heat pump, not its heating efficiency. Heating efficiency is