During the holidays, we were sitting around the kitchen table at a friend’s home, having some interesting conversations. There was a back-and-forth discussion about green issues in plumbing. Some myths were stated as fact and visa versa.

What started the conversation was the statement, “With my new instantaneous water heater, I’ll get the same temperature of hot water every time I open the faucet.”

I had to jump in and say it isn’t true. During the ensuing discussion, there was finally agreement that the temperature of hot water will change. An instantaneous water heater operates on a delta T, which means it constantly raises the temperature of the cold water the same amount, if you flow the water at the same flow rate.

In the Chicago area, where I live, the drinking water comes from Lake Michigan. As a result, the cold water temperature is warmer in the summer and cooler in the winter. The reason being is we live too close to the lake. The underground piping doesn’t have time to heat or cool the water supply to ground temperature.

For areas of the country being supplied with well water, the opposite is true. The water temperature from an instantaneous water heater will always deliver the water at the same temperature (when flowing at the same flow rate). With well water, the cold water is always the temperature of the surrounding ground.

Someone else commented it isn’t necessary to recirculate the hot water when you have an instantaneous water heater. Again, this is a myth. This was followed up by, “You don’t need to recirculate the hot water when you install a PEX manifold system.” This may be true or false.

When you have a long run of pipe to a fixture, hot water needs to be recirculated, whether the water heater is an instantaneous or tank-type heater. The engineering community suggests a wait time of 10 seconds. Others believe 30 seconds is OK. I happen to like 10 seconds, and that is what I normally try to achieve in a hot water distribution system. Otherwise, you are wasting water that needs to be treated.

When you have a PEX manifold system, if the manifold is located close to the water heater, you can get hot water delivered within 10 seconds for most fixtures. The manifold system uses a single line to serve the fixture and is often 3/8 in. in size. It doesn’t take long to empty the contents of a 3/8-in. line to have hot water arrive. Furthermore, the manufacturers recommend a maximum length of 60 ft. from the manifold to the fixture, resulting in hot water for most fixtures in less than 10 seconds.

This discussion was followed up with a statement that hot water recirculation is not green because it wastes energy to keep the water hot. As you know by now, that myth has been debunked for years. Recirculation of hot water is green.

Recycling, food waste myths

While cleaning up the kitchen table, the conversation switched to, “Recycling is a joke and there is no need to waste your time recycling.” I almost fell off my chair when I heard that comment.

It was followed up with, “It’s better to throw food waste in the garbage than down a garbage disposer.”

Both statements are myths. Realize that there weren’t any plumbing professionals at this kitchen table, other than myself. Although my beautiful wife smiled since she also knows a thing or two about the profession.

I almost wanted to say the plumbing profession started recycling before recycling became vogue. Every plumbing company has a brass and copper barrel for recycling. But rather than recycling, we call it scrap. Plus, there is money to be made in scrap. The aluminum, steel, cast iron and plastic industries all figured this out, as well. Scrap can be recycled. It does minimize the amount of garbage going to a landfill.

The interesting part of the discussion on food waste is that our friends have a garbage disposer in their kitchen sink. Yet they refuse to use it because, in their minds, it is better to put the food scraps in the garbage. They consider people who use disposers to be lazy.

That is a myth I have been unable to get across to our friends. Yet they know that every time my wife and I visit their house, I will use their disposer. They have gotten used to it. What they fail to understand is that every day, a 1/2 lb. of food waste per person in this country goes to a landfill, only to occupy space that is becoming more scarce. The garbage disposer recycles the food waste and converts it to fertilizer or energy, depending on the wastewater treatment plant.

One of the final topics of discussion was if it is green to shower together. We heard how our friends’ new home, currently under construction, will have two shower valves and two showerheads in the master bathroom. It was explained that it is a his-and-hers shower. This same new house will have an instantaneous water heater and PEX manifold system. They want hot water to get to the two shower valves quickly.

I’m not going to comment as to whether having two shower valves in one shower is green. Although I have been telling my wife since we were first married that we save water by showering together. Of course, the water conservation angle was simply a ploy. I guess showering together would have to go in the category of myth, or better yet, an illusion.

What this kitchen table discussion brought to light is that we as plumbing professionals still have our work cut out for us in educating our customers about green plumbing, energy conservation and recycling efforts in the plumbing community. Be sure to sell them on facts while putting their myths to rest.