How to find the phase shift (the horizontal shift) of a couple of trig functions Graphing Sine and Cosine with Phase (Horizontal) Shifts, Example 2. In this video, I graph a trigonometric function by graphing the original and then applying the phase shift.
Take the electric hot-water heater recovery times and divide them in half to get the recovery time for a gas unit. Water coming into a 50-gallon tank at 40 degrees takes just 53 1/2 minutes to reach 120 degrees. For 60-degree water entering the tank, calculate about 40 minutes needed for the water to reach the 120-degree temperature. For 70-degree water, it would take 33 minutes.
I live in MA and the average water heater replacement install is about $100. It takes about 30 to 45 minutes. Maybe you are including the heater? Cost for a water heater here is 3 to $400. I personally have not had to pay for the replacement heater, as I buy one with a 5 to 7 year warranty, and they usually need replacing, just under my warranty time.