We often come across existing installations which are not only ineffective or in disrepair but are highly energy inefficient and costly. We have recently replaced an old system in an inner city block of 36 dwellings. These were a mix of leaseholder owned and social housing.
The block had 9 ventilation shafts and the extractor fans were located in housings on the roof. Each shaft descended through 4 floors and through the centre of each dwelling. The bathroom and WC were internal and separately vented into the ducted system. The ventilation system was in bad repair, required a high degree of maintenance and often was out of commission so the occupants had no ventilation at all. In addition the system did not comply with building regulations as there was no fire protection between the dwellings – a requirement for ducted systems.
When the system was running it was operated continuously and the 5 fans required 700W per hour each, using a total of 3500W per hour. Assuming 1000W costs around £0.09 per hour, then operating this solution cost the building owner £0.315 per hour or £2759.4 per year when run continuously.
The RHL solution was to replace the roof mounted fans with a FOX Fire Safe fan in each dwelling. The FOX Fire Safe is a specialist two-room (bathroom and WC) fan with timed overrun. Its fire safety properties are due to an intumescent seal contained within the metal connecting section which expands when exposed to high temperatures.
The fan has two interchangeable intumescent cartridges so that the installer is able to easily place the cartridge as required. One intumescent outlet connects to the ducted system and the other provides fire protection for the second room. We installed the fan into the WC and connected this into the existing ducting. The bathroom was connected through the internal wall to the fan and ducted through the same extract point.
These low-watt fans operate on an overrun proportional timer activated by the light switches in either room and require only 4W per hour as they use two energy efficient MagLev motors, offering great efficiency, quiet operation and exceptionally long life (up to 50,000 hours of operation).
It is assumed that under general usage an intermittent fan runs for 4 hours within any 24 hour period. By comparison therefore for all 36 properties these fans would cost £0.05 per day or £18.25 per annum. Not only did this solution provide tremendous cost saving but all tenants had control of their own ventilation solution, the building now complies with building regulations and an added benefit is that sound transmission was reduced making it the ideal solution for communal ducted systems.