Reply To: Bottom Insulation

The Tank Bottom Insulation Reply To: Bottom Insulation


If condensation is a problem it means the place where condensation is located is cooler than the surrounding air. If surrounding air is 100% relative humidity then cold water lines and bottom of WH will be locations of condensation.

Water in an electric water heater (without a recirc pump) will stratify out very well. Hot water is less dense than cold water and therefore hot water floats on cold water. To prove this set an electric WH top thermostat at 130F and the lower thermostat at 110F. The next day take a long shower. You will start with a hot/cold mix. It will not take very long before you find yourself throttling down the cold so in a minute or two you will have a hot-only shower.

Cold water entering the WH either enters the bottom or flows from the top through the dip tube so it effectively enters at the bottom. Water temperature at and above the lower element will be at the lower thermostat set point. One inch below the bottom element WH temperature will be cold water inlet temperature. For a concrete slab to draw heat from the WH would require the cold water to be relatively warm compared to the slab. Not likely for normal setups. If you have two WHs in series or a water heater heat pump or any other means to heat incoming water to the WH, then you would have heat loss through the bottom. But then you will not have condensation issues.


Water Heater Rescue

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