Modern homes have requirements for heating/cooling, ventilation and insulation. There is some confusion as to whether installing a heat pump will provide your home with sufficient ventilation. There is also the question of whether installing a ventilation system will heat your home sufficiently. The simple answer is no. Ventilation is not heating and a healthy home needs fresh air, with a minimum room temperature of 18°C recommended by the World Health Organisation.
For the most comfortable and healthy environment your home is likely to need both a heating device such as a heat pump and a mechanical ventilation system to ensure adequate fresh air is being circulated through your home. Neither system alone will do both to a high enough level to make them a one-stop solution. Installing insulation should also be taken into account as not only does it reduce heat loss but can also help to reduce mould growing on walls and ceilings, providing a healthy and safe environment to live in.