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Q. My home was built in 1979. We are on a well with a water softener that uses salt and, as far as I know, it still has the original hot water heater not leaking yet. I put a thermal fiberglass blanket around it and turned the thermostat down too.The water is being heated by LP bottled gas at $4.45 a gallon with a $15.00 delivery charge and average 10 gallons per month. Can you tell me which source of heating water is the most efficient?
We have an automatic dishwasher, 2 & 1/2 baths and just the two of us. I contacted a tankless hot water system sales person. He was very persuasive against us getting one, stating it would not be able to allow someone to shower while the dishwasher, washing machine is running or someone else was also taking a shower and an exorbitant installation cost of $3,000. to $5,000. and we would have to change our life style if we got one. In our first home we were total electric. I had a 7 day 24 hour timer on the hot water tank also wrapped in a thermal fiberglass blanket. It was 25 years old when we moved.A. Since your current gas water heater is likely the age of the house (29) then I would seriously consider replacing it soon. Water heaters are listed lasting seven to twelve years on average but water heater longevity is a function of water quality and use plus the quality of the water heater itself. Gas water heaters seem to last longer than their electric cousins. I don’t know for sure if the metal jacket tank walls are any thicker than an electric but they just seem to perform longer.
You have wisely conditioned your well water which makes the water less aggressive towards metal pipes and things like water heater tanks. However you can’t really know the condition of the metal of the water heater tank because they wear from the inside out. Frequently they go bad at a welded seam or a pipe connection. Remember that a water heater tank is always under pressure and will often give no warning when it lets go at a weak point. I’ll sometimes see wetness at the bottom of the tank unexplainable by any other cause but a leaking tank and I tell the owner to shut water off to it immediately because the flood is imminent. But most often homeowners learn that the water heater is shot by going down to the basement and stepping in warm water as they get to the bottom of the stairs. I’ve come to the position that if a water heater tank makes it to age 20 it just might be a good idea to line up its replacement. Using a conventional gas or electric water heater will always be a bit energy wasteful due to the very way they are designed. Water heaters take a quantity of water in at roughly 55ºF and heat it up to about 120ºF and hold it at that temperature until you call for its use. Then more cold water comes into the tank and gets heated until you again call for it. It called stand-by heated water. The energy lost holding the water hot is what diminishes the energy efficiency of those heaters. Modern dishwashers heat their own water these days but clothes washing and bathing will be the hot water consuming activities that impact your energy usage most for hot water. I ran some rough numbers comparing the cost of your gas against electricity for the same quantity of heated water over the month’s usage and even at current exorbitant rates electricity actually worked out a tad cheaper. On demand, or tankless water heaters are very efficient when comparing energy in to energy out. Gas is the only really good tankless type in my book. They make electric models but pull so much power during use that significant wiring or even rewiring would be required to install one. It would seem to me that the key to placing the proper sized tankless heater in would be a simple inventory of your usage. The cost quoted sounds familiar to me but what I’m seeing these days is as the costs of the base energy source escalates, the payback periods for installing more sophisticated appliances become shorter and more attractive. You could perform a lifecycle cost analysis to learn when that break even point-- in today’s costs and dollars-- arrives. Might be sooner than you think. And I’ve got news for you, whether you get a tankless water heater or not, your, and my, lifestyle is going to change-- if it hasn’t already.