Integral air source heat pumps
An air source heat pump can be completely integrated inside the unit at the factory if no DHW or cold water provision is available on site and there is no opportunity for them to be retrofitted. It comes either with a two heat exchanger system for changeover between heating and cooling mode, or a four heat exchanger system for greater operational reliability.
This is also a good choice if the air handling unit is not able to be integrated with the existing hot water or cold water network or where this is not desirable. No external pipework is necessary in this case.