If you are planning on building a new home then now would be a great time to plan your plumbing layout for an energy and water efficient plumbing system that will end up saving you a whole lot of money and add convenience to your life.
If you already have a home, then there are still economical steps you can take to improve your plumbing efficiency and have a greener system environmentally and save money water and time when using your hot water system.
Cold Water Plumbing
When it comes to an efficient residential plumbing system it’s all about the hot water. The cold water system probably can’t be improved on. When you want cold water you turn on a tap. There is no waste built into the system, unless you have leaky pipes or something. Your cold water system doesn’t consume any energy either.
Hot water is another story. The hot water system consists of the water heater and the hot water plumbing. Obviously the water heater has a lot to do with the efficiency of your system. Some water heaters are better than others. You may have the old standard storage type gas or electric water heater, or a tankless water heater, or even a heat pump or hybrid water heaters. And let’s not forget about solar water heating.
For the sake of simplicity I’ll just assume you have a storage gas water heater. Most people do. Although the water heater is an important source of efficiency, I won’t get into water heater specifics here. I want to address the piping system and plumbing layout, as these are often not considered when building a new home, or the installation cost is minimized.
Hot Water Plumbing Layout
The main source of inefficiency in a residential plumbing layout is the length and location of the hot water piping. With the hot water plumbing, when you finish using the hot water you generally leave hot water sitting in the pipes where it simply cools off.
That stranded hot water costs a lot to heat. Letting the hot water cool off in the pipes is a major source of energy inefficiency. Then, the next time you desire hot water you have to run the cooled off hot water out of the pipes before you can get your hot water. So not only did you lose the heating energy, now you are running water down the drain too. Not very green.
If you are in the planning stage you can make sure your pipes are as short as possible. The shorter the hot water runs the less energy and water you will waste. Try to locate the water heater as close as possible to the most frequently used fixtures.
Make sure you insulate your hot water pipes. Insulating the pipes will reduce the amount of time you need to run water down the drain while you wait for the hot water to arrive. Shorter waits are also a convenience for the user.
Don’t oversize your pipes. Larger pipes hold more water and so will waste more water along with more heating energy. Most fixtures these days are low flow fixtures and thus you won’t be able to get a higher flow rate with larger diameter pipes. You do however, need to follow your local building codes. As far as hot water pipes go, generally smaller diameter pipes are green.
If you already own a home, there are things you can do to mitigate the energy and water losses associated with the hot water plumbing.
Install a demand hot water system. A hot water demand system will eliminate running water down the drain while you wait for the hot water to arrive. These systems use a small pump to pump the water from the water heater to the fixture without running water down the drain. They utilize the cold water piping to return the cooled-off hot water to the water heaters. When the hot water reaches the fixture the pump shuts off to prevent putting hot water into the cold water line.
There isn’t much you can do to eliminate the loss of heating energy due to the cooling off of the hot water left stranded in the hot water pipes after each use, but at least you won’t be wasting all that water.
If your hot water pipes are not insulated, and you can get to them, it’s a good idea. Also your water heater should have heat traps installed to reduce the leakage of heat into the pipes when they are not in use.
For a greener hot water plumbing system the rules are keep the pipes as short as possible, insulate the hot water piping, and install a hot water demand system. You will be glad you did.