How long for water to go cold when heater loses power?

Question

I woke up an had an ice cold shower this morning, because my water heater's circuit breaker had tripped and cut the power. Thinking back, my hot water was only warm on Monday morning, and we had a big lightning storm on Friday that was messing the electricity. Could it really have taken 3 1/2 days for the water to drop to room temperature?
The heater holds 52 gallons, and of average efficiency/insulation for a 5-year-old heater. How long would one expect in order to lose all the stored heat for that size of tank?

Answer 1

You have an electric water heater, so there is no draft through it as there would be in a gas heater. The heater is probably in a closet where there is little or no air flow past the outside. The smaller the difference in temperature between the heater and the room, the more slowly it drops. All of these combine to make the drop in temp rather slow. Running cold water in drops it much faster.

Answer 2

52 gallon water heaters have 2 heating elements. the average water heater temperature setting is 130-135 degrees Fahrenheit. The average water supply temperature is 50-60 degrees. As hot water is being used, cold water is entering the water heater, and is what moves the hot water out of the water heater, to your fixtures. The possibility is that only one water heater element was working giving you the warm water, and finally the other element gave out as well, and/ or a safety switch tripped, cutting off all power to the water heater. Depending on the hot water demand in your household, it could stay warm for a short time.

Answer 3

These tanks are insulated quite well. You can have hot to warm water for a couple of days after an outage or blown fuse. However, once you start using the hot water, cold water comes in to replace it and the temperature begins to drop faster.