Changing Watts on Water Heater Element – Water Heater Q & A ©Depositphotos.com/Goodluz Question- “Can we change a 3500 watt heating element on the water heater to a 3800 watt element?” Answer- You would need to read the electrical rating on the water heater because it is possible with some but not others. Ask the Plumber2018-03-05T18:10:24+00:00