This luxury 5* Marriott Meridien Hotel in Barcelona, Spain, has demonstrated that an eco-cistem™ installation can halve the water used for flushing toilets compared to a traditional toilet cistern. Rolled out to 100 bedrooms, the savings would equate to 1.4 million litres of mains water saved each year.
The senior management team and the Director of Environmental Sustainability at the Marriott HQ had the foresight to engage with eco-cistem during its final stages of development. As part of their sustainability drive, they agreed to a trial, and an eco-cistem was retrofitted along with equipment that monitored the water consumption of the cistern and recorded the actual number of flushes made during the trial period. The latter is a statistic that is very useful and yet not readily available.
The team also carried out a further retrofit installation of eco-cistem in a different high-end hotel in Barcelona, allowing the data obtained from both hotels to be compared.
eco-cistem is a concealed toilet cistern that can be installed with any brand of toilet. It has been designed to prioritise using condensate water from neighbouring air conditioning units to flush toilets. Even the smallest 1.75 kW air conditioning unit produces around 1 litre of condensate water each hour, which is normally piped directly into the waste. In an eco-cistem™ installation, this condensate is piped into the top chamber of the toilet cistern and is used to flush the toilet. Mains water is only used if there is not enough condensate to flush the toilet, so there is never a reduction in performance. Whilst eco-cistem can be retrofitted in both domestic and commercial premises, it is particularly well suited for hotel new builds or refurbishments. The product effectively gives free flushing water, so it is a perfect sustainable guest upgrade.
The trial at the Marriott in Barcelona monitored the water used by an eco-cistem installation over an eleven-month period and has shown that it uses 50% less mains water than a traditional cistern.
Cumulative Water Consumption
The monthly performance of the eco-cistem was also monitored, which, as expected, shows a reduction in the savings in cooler months due to reduced occupancy, and potentially less use of the aircon unit that feeds it.
There are a number of factors that affect the performance of eco-cistem, which include external temperatures, the internal room temperatures set by the occupant, and the number of toilet flushes made daily. So, at the same time as recording the water consumption, it was also useful to record the number of toilet flushes made in the room. The number of flushes in this trial followed a similar pattern to the monthly water consumption, suggesting that occupancy of the room decreases during cooler months, likely due to the hotel being located in a high tourist area. The monthly flush count on the eco-cistem toilet cistern averaged over the year at 15 flushes per day.
As water not only continues to be in short supply but will undoubtedly become much more expensive over the coming years, an eco-cistem installation has been proven by this trial to save at least 50% of the mains water used compared to a traditional toilet cistern.
Using the data from this monitored trial in the Marriott hotel, the following model was worked up to demonstrate the return on investment (ROI) in installing this eco-cistem innovation and rolling it out to a 100-bedroom hotel based in Barcelona. The slight increase in cost of the eco-cistem cistern would be offset in the first year by the savings made on the cost of fresh water. From an environmental view, a 100-bedroom hotel based on this model from the live data could save 1.4 million litres of fresh water per year.
