Sunday, January 31, 2010

Saving energy costs by a simple design change

Think of the last time when you operated a 2-handle faucet. Which handle did you turn first? Was it the left handle or the one on the right? Chances are that if you are right-handed, you turned the left tap first and if you are left-handed you turned the one on the right first. If this was any different, please let me know; I'd be curious to know.

Based on quick internet-based research, it seems that the installation instructions for most 2-handle faucet systems indicate that hot water be connected to the left handle and cold water be connected with the right one.

Given that almost 80% of population is right-handed, what that means is 80% of the times when a faucet is operated, the left handle is operated first, which delivers hot water. Now, I do not have data on whether people prefer hot water when they first operate the faucet but I'd guess that there is a significant combined percentage of people who either prefer cold water or who don't care versus the ones who prefer hot water at the first go.

Given above, to reduce energy costs one may want to interchange the hot and cold water connections at the time of installation i.e., connecting hot water to the right handle and cold to the left handle. This of course can be interchanged if the premise has predominantly left-handed folks. Better yet, with a simple design change, this configuration choice can be made dynamically by having a knob that controls the flow of the water to either handle.

The savings achieved at a single premise due to this change depends on several factors - frequency of opening tap, percentage of left-handed/right-handed people using a particular tap etc and may not be significant however economies of scale can be achieved if the modified faucet was used by a large population.