What uses less energy: 40-gallon gas water heater, or a 5 GPM electric tankless unit?
I understand a 40-gallon gas water heater uses less energy than a 40-gallon electric water heater, but what about 40-gallon gas vs. electric tankless? What uses less energy: 40-gallon gas water heater, or a 5 GPM electric tankless unit?
You need to re-word your question, and probably give a lot more information. Energy is Energy, and it takes the same amount gas energy to heat a gallon of water as it does for electric energy.
Water heaters slowly lose heat to the surroundings, so you tankless has the advantage that it only heats the water, and not the surroundings. How much energy you save depends on your pattern of water usage. I considered a tankless because after my morning shower, the house sits around empty for the rest of the day. My friend had the opposite problem ---- he got a tankless because his family was so big, that his tank-type water heater could never keep up to the usage.
What you possibly intended to ask is "which costs less to use?". Well that depends on what you pay for gas and what you pay for electricity. Also depends on monthly fixed charges --- if you get the electric tankless do you still have a gas bill coming in every monthly --- does it have a fixed monthly charge if you are using a lot of gas or not?
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