Q. I have an eight-year-old AO Smith 74 gallon hot water heater. Just recently it started not providing enough hot water to last even one 25-minute shower. It used to be good for about 40 minutes. I have been turning up the heat setting on it, but now it is all the way up to "very hot" and I am still running out of hot water. Is it something that would be cost effective to fix or is it just time to upgrade to a more efficient, larger model?
A. There are a couple of things to try first before assuming the dip tube is defective, which it could be, but not likely. Newer tanks have plastic dip tubes that are not prone to rusting, damages or corroding. Nor are they always easy to remove or install.
Try low flowing showerheads. Installing them will help plenty. Run the water volume lower during showering to use less water. Take shorter showers, especially in winter months. It takes incoming cold water to push out the hot water. Thus dilution takes place. The colder the outside temperature, the colder the incoming water will be. Thus the dilution process happens sooner. Pace and space hot water usage between showers to allow time for water to reheat. Avoid doing dishes and washing clothes during brief time spans. Doing so allows recovery time between high demands.
All the above is intended to avoid dip tube removal time and work - only to discover the tube is fine and the problem is not resolved. Tube replacement will not ensure a positive solution. Once all the changes are made, an improvement should be noticed. Once the weather warms up, most likely the problem will be resolved.
Pertaining to the shower faucet: Change the shower faucet valve. If it is one of the single lever types, there is that rare possibility the internal mixer valve insert is reacting to the hot water. It will allow more cold water to pass through than hot. This happens when the insert in the valve becomes worn-out or defective. Often this can be noticed at other appliances which use plenty of hot water and the tanks are 40-gallon sizes. Water remains hot at other appliances but not in the shower where single lever faucets are used. Give that a try and see if there is any difference. If not, then the problem may be with the dip tube. Or there is the very rare possibility of a lack of dip tubes in the tank.
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