Answer:
True
Step-by-step explanation:
True. Air-source heat pumps are considered the most efficient type of heat pump because they access a renewable energy source, which is the air outside the building, and they have the highest cooling efficiency and lowest annual operating costs compared to other types of heat pumps.
They are also considered environmentally friendly because they do not produce greenhouse gases. However, the efficiency of air-source heat pumps can be affected by extreme temperatures, so they may not be suitable for all climates.