Hot showers are great. They can wash away even the worst of days and leave you feeling warm and refreshed. But hot showers can also be wasteful. Around 20% of household energy is used to heat up water, and a large percentage of that is used in the shower.
Everyone can save some hot water—and the energy it takes to heat that water—by taking shorter showers, but there are other things you can do to make your shower less wasteful and more energy efficient.
Low Flow Showerheads
One of the best and easiest things you can do to make your shower more efficient is to install a low flow showerhead. Current standards mandate that showerheads must have a flow rate no greater than 2.5 gallons per minute (gpm) and water pressure no higher than 80 pounds per square inch (psi). This is in contrast to older showerheads that can have flow rates of up to 5.5 gpm. Switching from an old showerhead to a new, low flow one can help you use between 25% and 60% less water in your shower.
Many modern low flow showerheads are relatively inexpensive and don’t feel like they are low flow. The water pressure is still great! You can find low flow showerheads at most home improvement stores, and you can even get some for free if you schedule a no-cost home energy assessment with Mass Save.
Drain Water Heat Recovery
Another problem with the energy efficiency of a shower is wasted hot water. We expend a lot of energy heating water up to warm our skin, but the water remains hot once it’s finished its job and goes down the drain. The heat in that water then dissipates as it goes through our pipes, thereby wasting most of the heat energy that it once held.
This problem can be solved by a drain water heat recovery (DWHR) system. A DWHR system consists of a wide, straight copper drain pipe with a smaller pipe snaking around it’s exterior. The hot shower water drains down the big pipe, while cold water is pumped up the smaller pipe and into the water heater.
Since copper is a great heat conductor, it allows the heat of the draining hot water to pass through the walls of the pipe, and heat up the cool water entering the water heater.
This process leaves the cool water much warmer as it enters the water heater, which will then require less energy to heat up. DWHR systems can raise the temperature of cold water from 50 degrees to up to 75 degrees during its trip through the copper pipes.
This is a great way to salvage the already expended heat energy. It’s great for your carbon footprint, and it can also be great for your energy bill. Prices for these systems will vary based on the price of copper, but according to the U.S. Department of Energy, a $300 to $500 DWHR system will typically pay for itself in 2.5 to 7 years depending on your climate and water usage.
That being said, the cost-to-benefit ratio of these systems is far from clear. Copper prices can vary a lot, and whether or not it makes sense to install a DWHR system should really be looked at on a case-by-case basis. While it may not make sense for everyone to install a DWHR system in their homes at the moment, builders should definitely be looking to incorporate these systems into new homes and larger facilities like gyms, apartment buildings, and hotels.
As DWHR technology continues to improve, the case for installing one of these systems will hopefully begin to make sense for more homeowners and home builders. This technology is still in its relative infancy, but the future potential of DWHR is really exciting!