MANY TIMES, we as hydronic heating contractors, are overlooked when it comes to providing domestic hot water for the homes we’re heating. This is quite unfortunate because the consumer has already paid us a substantial sum of money to set up a hydronic heating source with considerable firing capacity. The only additional pieces necessary are the storage tank and heat exchanger, and possibly a valve or pump to make things work.
The primary reason we’re overlooked is because plumbing contractors typically handle DHW needs. I realize that many of you reading this are both heating and plumbing contractors, and nothing derogatory is meant to either of these brethren. It’s just that when opportunity knocks, you should answer.
What are the advantages of using the space-heating boiler to produce DHW? There are many, and we’ll explore them all.
First, and most importantly, is the energy conservation issue. The typical gas-fired stand-alone DHW tank-type water heater has a continuous standby loss occurring right through a large hole in its combustion chamber and storage tank. This loss occurs every minute that the burner is not on, about 20 to 22 hours per day for a typical American residence.
Even when the burner is on, the combustion efficiency is far below that of the typical off-the-shelf hydronic-heating boiler. Most boilers with an input of less than 400,000 Btuh are required to have a flue damper, which negates the standby stack losses of the appliance. In other words, the heat is kept in the heat source, and not allowed to trickle up the flue pipe, dragging the contents of the consumer’s wallet along with it.
There is not a 3- to 4-in. hole right through the middle of an indirect-fired storage tank giving its heat up to the atmosphere. It’s a much wiser use of our precious fuels.
That’s the conservation issue. How about the hot water availability issue?
I met a man once who had not had a decent hot shower in the morning on a weekday in the five years he had lived in his new home. You see, he lived in a house full of beautiful women — his wife and their two teenaged daughters. Does anyone know how much hot water a teenage girl uses during a given shower? It depends on whether she needs to shave her legs, and then there’s the shampoo, the shampoo pretreatment and the conditioner.
This poor guy had never experienced a hot shower during the week because the women in his life beat him to it. He installed the largest residential water heater he could find, and still there wasn’t adequate hot water when it came time for his shower. He even tried showering at night. He had adequate hot water at night, but after having slept in the same skin all night long, if he didn’t shower in the morning, he could see a difference in his sleep-wrinkled skin and pillow-wrinkled hair. He just had to shower in the mornings.
If he got up early enough, before his wife who woke up at 4:30 a.m. to get her hot shower, he could get a hot shower, but then he was awake fully three hours before he needed to be, and one of his daughters would probably be shorted hot water, which he would have to hear about for days on end.
So, he just decided to live with the fact that he’d probably never get a hot shower during the week, and go on down the road of life.
Then one day, during the annual Spring Home and Garden Show, Mr. Tepid Shower happened across our booth, and noticed the 119-gal. storage tank sitting in our booth.
"I didn’t think they made anything larger than 75 gal.," he said with glee in his voice.
I explained to him that in the typical residential stand-alone gas-fired applications that 75 gal. was about as big as they get. I then asked him how he heated his home, to which he replied, "With a boiler, we have hot water heat."
"Aha," I thought to myself, "I’ll bet this guy would be interested in buying this tank and connecting it to his home heating system." And he was, and we did, and he called me daily for the first week thanking me and our company for allowing him to have a hot shower during the workweek.
He has since referred numerous customers who were also suffering from cold shower syndrome and who also had hydronic heat and didn’t know that there were alternatives to gas-fired tank-type water heaters.
Do you know why these homeowners aren’t aware of this different method of heating hot water? It’s because we didn’t tell them about it. Oh, sure, initially it will cost more to be installed than the typical stand-alone water heater, but we have so many benefits to offset the consumer’s cost-driven fears. Benefits like a nearly limitless supply of hot water, less money spent for heating water, substantially longer tank life and better utilization of a piece of equipment (the boiler) that they are going to have to pay for regardless of whether they go with your DHW option.
Generally, if these benefits are properly spelled out and presented, consumers’ reluctance to the price is overcome almost immediately. Especially if they’ve never had a hot shower during the week.
Tune in next month as we continue to discover the benefits and opportunities in heating domestic hot water. Until then, Happy Hydronicing and Happy New Year!
Mark Eatherton is a Denver-based hydronics contractor. He can be reached via e-mail at [email protected] or by phone at 303/778-7772.