Even if you have a solar thermal array pumping hot water through your into your recycled copper sink, the plumbing connections could be more green. Some pipes are more eco-friendly than others, and plumbing purchases and habits can maximize water and energy savings.
Comparing Plumbing Pipe Materials
PVC (polyvinyl chloride) is the most widely used pipe material, followed by iron, copper, and ABS (acrylonitrile-butadiene-styrene), another common type of plastic used in drainage pipes. New polyethylene and polypropylene products are more eco-friendly but less widely available. How do they all compare in materials, energy inputs and lifespan?
Iron and copper: Metal pipes often have high levels of recycled content, and are easily recycled. However, even recycled metal pipes are energy-intensive. Melting and forming copper and iron products at extreme temperatures consumes more energy than the production process for plastic pipes.
Metal pipes are stronger and more crack-resistant, but they also corrode faster, adding potentially dangerous residues to water. Werea KIMAB, a European corrosion and metals research institute, estimates iron drainpipes have a 50-year lifespan. However, epoxy pipe linings add up to 50 years of life to metal pipes while also improving the water quality by adding a barrier between the water and corroding metal.
PVC: Hard plastics are largely made with raw petroleum-based chemicals, and discarded pipes mostly end up in landfills. Some PVC products can be recycled, but recycling is expensive and the market demand is low because virgin PVC is cheap. However, environmental costs may be high. Greenpeace and other environmental groups oppose all use of PVC, which they say emits possibly harmful chemicals throughout production, use, and disposal. The Uni-Bell PVC Pipe Association estimates PVC pipes will last 100 years under normal conditions if properly installed.
Other plastics: Polyethylene and polypropylene are generally less toxic. Aquatherm, a German company, makes polypropylene pipes that are listed as GreenPeace International's only "future-friendly" plumbing product. These alternative plastics are more easily recycled, even though most available products do not have recycled content -- and they need to be replaced faster than PVC or lined iron. Aquatherm claims a 50-year lifespan for its pipes.
Save Energy, Not Plastic
Eco-conscious consumers should also focus on saving energy and water. Regularly check for leaky pipes, and shop for low-flow showerheads, dual-flush toilets and water-restricting aerators. Homeowners can also find ways to reduce hot water usage and reuse "gray" wastewater if possible.
Wrap the Pipes
Finally, no matter which type of pipe is used, hot and cold water pipes should be insulated wherever possible. Pipe insulation is cheap and easy to install. Simply wrap pre-slit polyethylene and neoprene foam tubes around the pipes, then tape or clamp them shut. Foam pipe insulators are estimated to cut heat loss by up to 80 percent, and they keep cold water pipes from sweating. They can raise water temperatures four degrees, allowing a lower, more energy-efficient setting on water heaters.
Plumbing pipes made of new plastics may be hard to find but easy on the environment. Homeowners also should find ways to cut energy and water usage in plumbing decisions.