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Facts about hot water – tanks vs. tankless
It is very common to have clients ask my thoughts about “upgrading” to an instant hot water tank. These tankless hot water systems are very popular right now and are commonplace in new construction. They take up less space, provide endless hot water, and are acclaimed to be cheaper and more efficient than the traditional, cylindrical tanks. Who wouldn’t love all that! For some folks they can be a sensible investment, but there are some questions to consider before you make the jump to the tankless hot water train!
Will a tankless tank really save me money?
Heating water costs us in three ways. The water we use, fuel consumed to heat water, and the appliance purchased to make it all happen.
First, there is little difference in water consumption for a traditional tank or tankless system… Unless your teenager or spouse, who LOVES long hot showers, discovers the bottomless hot water supply. What used to be a fifteen minutes shower could become thirty minutes or maybe an hour! Or the tub could be filled to the brim. And in both situations you pay twice – for the water used and fuel consumed!
Second, as for fuel, the more you use the more you pay. A traditional 40-gallon hot water tank will use approximately 35,000 BTU of natural gas or 4,500 watts of electricity. The burners/elements will heat periodically throughout the day to keep the water at the 120-degrees we enjoy. Sounds like a lot until you see that a tankless water heater operates at 140,000 to 200,000 BTU of natural gas or 28,000 watts of electricity. Heating 50-degree water to 120-degrees takes a lot of energy and these burners/elements run continuously until the demand for hot water is satisfied. Bottomline, you save money only if you use little hot water. If you use it frequently throughout the day or use a lot of it, you’ll probably not save much. Tankless is great for professionals and couples working away from home most of the day. Tankless is not as efficient for stay-at-home parents with a quiver of little ones.
Third, I ball park the cost of a traditional 40/50 gallon hot water tank at about $1,000 including installation. The cost of a tankless tank varies and I’ve heard from plumbers numbers double and even four-times the amount of traditional tanks. Adding to the cost of the tankless unit is the need to upgrade the power or gas to provide sufficient fuel for the energy numbers referenced above. Wire and piping is not cheap and a licensed electrician or plumber must do this work.
How long will a tankless unit last?
We don’t really know since they have not had long, widespread use yet. Because tankless no longer have a ceramic-coated steel tank the most common issue of leaks should be rare. Manufacturers are estimating their life span as twenty years, about twice as long as traditional tanks. As an inspector, I still advise my clients that they will last ten years until I see a longer track record of these appliances. If these prove to last twice as long, they could prove to be more efficient in the long run.
What else am I missing or over-looking?
In the event of a major natural disaster like an earthquake, seismic straps ensure every home has 40 to 50 gallons of potable water. Your hot water tank is an emergency reserve of fresh, drinkable water. With the advent of the tankless system this built in safety feature is no longer present in every home. I would encourage you to consider some sensible fresh water solutions if you choose to convert to tankless. By the way, I was a young husband and father during the pandemonium of Y2K so I am cautious to about offering disaster preparedness tips; but this is a cheap, simple way to be prepared!
