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Originally published in Hotel Engineer 16-2-2011

A study recently presented by Sydney Water at the Australian Water Association 4th National Water Efficiency conference in March 2011 has shown that hotels are still playing their part in water conservation, and saving money along the way.

 

Audits were undertaken on 24 business hotels in 2010, and the water use was compared with a similar series of audits from 2005. The results are in table 1. It showed that the hotels had reduced water consumption L/guest/night by an average of 241 L/guest/night or over 40%.

A significant saving: on a large hotel with 400 guests that would equate to saving over $120,000 a year on the water bill alone.

 

Average for 24 business hotels KPI

L/guest/night

 

2005 569
Actual 2010 328
Target 2010 267

Table 1, shows average figures for 2005 to 2010, including the new recommended targets for hotels.

 

As part of the audit, the hotels were recommended further water saving ideas. The target figures were based on completing all projects with a less than three-year payback.

Across all hotels that averaged a further 20% water reduction.

 

Table 2 shows the actual and recommended target average L/guest/night when broken up by major water using facilities.

 

  2010 Actual

 

2010 Target
Hotel facility

L/guest/night

Cooling tower no laundry 300 229
Cooling tower, with laundry 416 344
     

 

So what has changed since 2005?

There were two significant areas of improvement between the audits.

 

Better maintenance

In the 2005 study the overnight base flow (leaks) averaged 30 percent. In the 2010 study the average was eight percent: a significant reduction. Anecdotally hotel engineers attributed that to better use of main meter monitoring equipment, installing and reading sub-meters and having staff report leaks.

 

Guest room retrofits

There has been an increase in the use of more water efficient fittings. Table 3 shows the change to water efficient device over the last five years. Technological improvements mean that hotels who installed water efficiency devices 5 years ago, could install even more water efficient fixtures now.

 

Guest room fittings Flow/flush volume 2005 2010
Shower- >=9L/min 20% 40%
9-12L/min 20% 30%
12-15L/min 20% 30%
=<15L/min 40% -
Basin   A mixed combination of 6, 9, 12 and 15 L/min 40% <=6 L/min

55% 8 to 12L/min

4% 12 to 20L/min flow

Toilet 4.5/3L dual flush - 50%
6/3L dual flush 50% 46%
11/5.5L - 4%
11L single flush or larger 50% Nil in guest rooms

Table 3: hotel fittings comparison from 2005 to 2010 hotel audits.

What were the additional water savings?

Recommended water savings across all 24 hotels in the 2010 audits totaled 604kL/day. The majority were leaks and maintenance issues.

 

Better maintenance

49 percent of all saving recommendations were related to maintenance issues, from leaking toilet cisterns to cooling tower set points set too low.

  • Six hotels had zero leaks; another five had leaks of less than five percent of their overall flow.
  • The highest individual leak captured on the audit was 17kL/day, due to a solenoid valve failure on a urinal cistern tank which caused it to overflow and flush continuously.

Guest room retrofit

42 percent of all savings were related to retrofitting guest room amenities. The proposed savings were based on retrofitting:

  • showers of 9L/min ( 26 percent of projected savings)
  • hand basin taps 6L/min (5 percent of projected savings)
  • toilets of 4.5/3L dual flush (11 percent of projected savings)

 

Savings sensitivity

 

  • Several hotels have already stated that the 9L/min showerheads available do not fit their hotel ‘brand’ and they would be unlikely to go lower than the 12L/min.
  • 6L/min basin flow was recommended as a maximum flow for basins. There is the potential for even higher savings as restrictor taps as low as 2 L/min are becoming more common.
  • Toilet retrofits, which made up 11 percent of all water savings in the audits, exceeded the three-year payback. So, although they were recommended in the audits, the water savings were not included in the target KPI calculation. Hotel engineers had already stated that most water efficiency toilet installations are not due to efficiency directly, but undertaken as part of a room renovation, where the style is for smaller cisterns.

Would it improve the NABERS rating?

A NABERS hotel water rating was included as part of the audit.

The average NABERS water rating across all hotels in the 2010 study was three stars.

If the hotels completed the projects recommended (all with less than three-year payback), projected NABERs rating showed the average rating should increase to 3.5 stars.

The best single improvement was from 2.5 stars to 4 stars.

 

So what does it mean to my hotel?

You can make some very real and cost effective savings by improving maintenance and fitting low flow showers and basins fittings. If you haven’t lowered your water use, tracked best as L/guest/night, in the last 5 years, you are missing out on some very easy savings.

 

The study “Water efficiency in business hotels’ is copyright of AWA, and results are also at the Sydney Water website

 

Wendy Hird

Author: Water efficiency in business hotels

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Below are examples of costs and paybacks for some of the recommendations in the 2010 hotel audit study.

 

Showers

Guest rooms are between 39% and 61% of a hotels water use (average 56%). Showers were estimated to be 65% of the water use in a room.

One hotel, with 15L/min shower heads, would save 30kL/day by installing 9L/min showers heads

  • 400+ rooms
  • cost of $56,000
  • savings $59, 400 ( water, sewerage, heating costs)
  • payback 0.9 years

 

Basin taps

One hotel with 12L/min flow rate basin taps, would save 4.1 kL/day by installing 6L/min taps

  • 170+rooms
  • cost of $5,100 (200 basin tap regulators)
  • savings $8,500 ( water, sewerage, heating costs)
  • payback 0.6 years

 

Maintenance

One hotel had leaks in cold water to guest room overnight at a rate of 39kL/day. Rewashering the toilet cistern rubbers -

  • 300+ rooms
  • cost of $19,000, savings $23,000 ( water, sewerage)
  • payback 0.8 years

 

One hotel had a cooling tower set point set to 1000ppm, but the conductivity probe was dirty and bleeding off at 680ppm.

  • Savings $2, 300 in water and sewerage (not including chemicals)