Stockton Home Inspector Dennis Hoffman, owner of Hoffman Inspections located in Northern California, raises the issue of When 50 Gallons is NOT 50 gallons or my is my shower COLD?
To answer this question, let’s go straight to the source and discuss water heaters. Most water heaters hold 40 to 50 gallons of water, but sometimes 50 gallons is not 50 gallons. This is a shocking misunderstanding about how much hot water you can actually get from a water heater. This reality has led to many cold showers and to very shallow water levels in hot tubs.
In order to understand this issue, let us consider some important vital statistics. The average shower will consume about 1.5 gallons of hot water per minute. Therefore, an average shower of ten minutes would use 15 gallons of hot water. The normal shower temperature is about 105 degrees F. You can see, as the hot water supply is being used and the temperature drops, the hot water supply would be less than 105 degrees F at 20 minutes of shower time. In comparison, a shower massage could conceivably use over twice the hot water in the same amount of time.
Standards:
We can broaden our understanding further, be reviewing some water heater standards. All water heaters are designed to supply a minimum of 60% of the total tank volume before the hot water supply drops 30 degrees F. This means that a 50 gallon water heater set at 120 degrees F, will supply a minimum of 30 gallons of hot water before the 30th gallon measures 90 degrees F in temperature.
OLD versus NEW:
Now let us compare water heater volume supply from the past, with the present. In the past, water heaters produced by manufacturers increased the hot water volume and were set at 140-150 degrees F. As a result, when a water heater set at 140 degrees F drew 60% of it volume, the ending temperature was 110 degrees F, which was still hot enough for showers. Unfortunately, these high temperatures eventually increased the risk of scalding, and today are no longer recommended by any water heater manufacturer.
WINTER versus SUMMER:
Even the season of the year can contribute to the temperature of your shower. In the winter, the incoming water supply is much colder and requires more hot water volume to obtain the same shower temperature. This means that the hot water volume in winter would be depleted faster than in the summer.
IDLE TIME:
One important way that you can guarantee a hot shower is to become aware of standby heat loss which reduces hot water supply. All contemporary water heaters experience standby heat loss. They are so well-insulated that the standby heat loss is very slow. This heat loss is not usually noticed until hot water usage stops, for any length of time.
To illustrate how this could happen, let’s create the following scenario. Before going to bed, you are not aware that your water heater is set at HOT position (120 degrees F) and that it can lose from 20-25 degrees F when not used. This means that the heater can drop as low as 95 degrees F, before the thermostat will fire. The standby heat loss is non-adjustable, and is directly related to inactivity. So, you wake up the next morning, jump in the shower, turn on the water and wait….You become very frustrated, and begin to wonder, “Why am I not getting any hot water?” To solve this dilemma (and create a positive outcome scenario) simply, turn on the hot water only, and let it run for a while (approximately 1-2 gallons). This will cause the heater to activate sooner, and improve your temperature and shower time.
Stockton Home Inspector, Dennis Hoffman with Hoffman Inspections offers a variety of building inspection services for residential or commercial properties. Dennis has been inspecting over seven years and done more than 2,000 inspections. Call Dennis at 209-369-0556.
Just wanted to say HI. I found your blog a few days ago on Technorati and have been reading it over the past few days.
I have edited the entry to better the content and resubmitted it today. Hope it is helpful.