You’ve probably heard of them, maybe because they’re starting to dominate the market of washing machines. Although energy efficient dish washers and dryers are slow to become competitive, low-water washing machines are so significantly water efficient in comparison to standard models that they’re becoming one of the first green appliances to quickly become worth their higher initial costs.
Why is this? Well let’s start by crunching some numbers. The average American uses somewhere between 80 and 100 gallons of water per day. Some of that tends to be shared usage, so it’s about fair to say that a family of four uses 300 gallons of water per day. That adds up to 109,500 gallons a year used by the average family. About 15% of that water is contributed to the approximately 400 loads of laundry done each year by that same average family. That’s right, the average family of four uses about 16,000 gallons of water a year just to wash their clothes.
Now that there’s low-water washing machine son the market, it’s possible to cut that consumption by up to 40 percent. That ends up adding up to hundreds of dollars cut from your utilities bill per year. But how do they manage to do this?
First let’s go over what a standard machine does to wash your clothes. A typical washing machine consists of a large porcelain or plastic basket seated inside a sealed drum that fills almost completely with water. The 3.0 cubic foot drum can hold about 22 gallons of water and, in larger machines, might even use up to 50 gallons of water per load.
Now there’s low-water washing machines, also known as high efficiency of HE machines, that use about 60% of that amount of water to complete the same job. There’s even one machine created by the British company Xeros that uses virtually no water, opting instead into special clothes cleaning pellets.
You’ve likely seen these HE appliances marked with the EnergyStar label; EnergyStar is an organization that manages the certification of high efficiency, energy-saving appliances. There’s a different set of criteria for each kind of appliance (and sometimes no set of criteria whatsoever, like in the case of dryers, which aren’t even worth rating due to their widely similar energy output). For washing machines, EnergyStar takes into consideration the machine’s water factor or WF. This is derived by taking the total weighted per-cycle water consumption (also known as the quotient or Q) and then dividing it by the washer’s capacity, which is generally referred to as C. Since 2009, EnergyStar washing machines have had to have a WF less than or equal to 7.5. In 2011, that number dropped to 6.0, and we can expect that number to keep dropping as technology advances further and the signs of global warming worsen.
So how do HE machines pull this off? They only allow clothing to soak up the amount of water they need by using sensors that can measure the amount of water needed based on the weight and moisture level of the clothing already in the machine. This keeps the machines from using more water than is necessary i.e. wasting it.