Semi-centralised supply and extract air system
with heat recovery via heat exchangers, constant air flow
If the layout of the building limits your options for a centrally sited air handling unit, e.g. in terraced housing, then you may need multiple medium-sized units so that each unit ventilates two or more housing units.
No extensive ductwork
A semi-centralised solution eliminates the need for extensive ducting, the advantage of which is relatively low system pressure falls, which in turn results in an energy-efficient and quiet system. Semi-centralised units can be served by a counterflow heat exchanger or a rotary heat exchanger.
The disadvantage, compared with a centralised system is that the number of service points increases, which then increases the servicing and maintenance costs.
Advantages
- Balanced ventilation
- Reduced risk of draughts and noise
- Several heat exchange options
- Guaranteed indoor climate
- Efficient heat recovery
Disadvantages
- Slightly more service points than in a centralised system
- Slightly higher maintenance costs
