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Plumbing and water efficiency myths Author: John Koeller and Bill Gauley 23 April 2009
Tags: Water efficiency, Climate Change / Sustainability, Counterfeit Product, Product Certification, Product Labeling, Products, Research & Knowledge, North America Page 2 of 3 | Single page

However, such tanks do not hold enough water to be useful for landscape irrigation. A typical 190L tank holds enough water to apply 25mm of water to about 7.5m2 of lawn. And after an extended dry period, when irrigation is most needed, the tank is likely to be empty.

Myth: Automatic irrigation systems are more water-efficient than manually operated systems (sin of vagueness).
Reality: Although automatic systems can be very efficient, several ‘real life’ monitoring projects verify that automatic irrigation systems are typically operated in such a way that they apply far more water than manual systems.

The use of ‘smart controllers’ (also known as weather-based controllers) can improve the efficiency of automatic irrigation systems, but only if they are programmed and operated properly and are connected to an efficient, properly maintained system.

Myth: Water-cooled ice-making machines use less energy than air-cooled machines (sin of hidden trade-off).
Reality: This argument was broadly accepted until water authorities and others began to investigate and quantify the amount of energy embedded in the water itself, before and after its delivery to the customer.

That is, all of the energy associated with water treatment, delivery to the customer and collection and treatment of wastewater was found to be significant. When all energy use is accounted for (including energy used by the machine itself), it was found that air-cooled machines are the most energy efficient.

What to do?

Avoiding the tempting and easy path is essential to ridding ourselves of greenwashing claims. That is, we must be diligent and question what we hear or read about supposed water-efficient products or practices.

We need to be sceptical and seriously investigate claims of water or energy savings. We need to ask questions and look for a scientific basis behind the efficiency statements.

Here are some items to consider when going through that process:

• Products and practices should be subjected to independent analyses and measurement by qualified authorities. Verification of actual water use under conditions in the field is highly desirable. When that opportunity is not available, independent evaluations in a laboratory may provide reliable information.

• Where possible, do not rely on ‘engineering estimates’ of water use. This approach is simple but exceedingly unreliable, for it provides little in the way of real-world operating context.

• Field and laboratory studies that seem to focus on gathering reliable water use data may be doing the opposite. Products that are non-representative of the whole (samples cherry-picked for use in a study may not represent those in the manufacturer’s warehouse) and failure to account for the statistical reliability of the study can readily invalidate findings.

• A full lifecycle cost analysis is essential for some products, particularly those with extraordinarily high operating and maintenance costs. Products are often promoted as ‘green’ without regard for these continuing obligations. Building managers and owners that discover these previously hidden costs may remove the product before its physical life has ended.

• Meeting and hearing from professional colleagues is always welcome, but success stories often show only one side. Individuals are reluctant to stand up at a conference and tell colleagues of their failed products or programs – only the successes are presented. We should always seek all the information, good and bad, before making a decision to proceed.

• People involved in green building design and specification development are often approached by sales engineers and marketers. Slick, convincing arguments for a product or practice that have little or no basis in fact can ‘romance’ a novice in the field.

Continued...



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