Is it sensible to work out how long it takes to heat your hot water tank? To set your timer.

I'm thinking, how long should it take from cold, to user temperature. I rarely run out of hot water, but the wife set it to come on at 4.30pm and go off at 7.30pm, the boiler clicking on and off throughout this period. If the boiler clicks off, does that mean its hot enough, or does the system build up the temperature in stages? I don't want to waste energy with trial and error, if someone can guide me roughly. Kind regards Mike

ac-dc8 years ago
It is possible that you would save more power putting more insulation around the heater and running it 24/7, than having it turn off and back on again. The reason is that it takes less energy to keep something at a temperature than to have to heat it all the way up again from room temperature, IF you minimize the losses. Even so, the most efficient could still be to both improve the insulation and have it turn off at a set time, although with more insulation you may be able to set the time it turns off even sooner than 7:30, not by a lot of time but it is a little, then a little less, etc, improvement to stretch the time running down as short as possible. However, since electricity and gas aren't very expensive in many parts of the world, I would rather be conservative and pay a few pennies more to never get caught taking a cold shower, especially in the winter when lost heat isn't really lost, it heats the house reducing furnace on-time. As for it clicking off, what happens is it heats up the water to the right temperature, it does not heat up in stages per se but there are two other factors. 1) For safety, or possibly as part of the design, it may cycle off the heating element before it gets overly hot, then cycle it on again and again until the water is at the right temp. This technique is often used in devices like inexpensive toaster ovens, but not so much in water heaters unless the designed-in ventilation is blocked. Evidence that this is happening would be that it cycles on again after only a very few minutes, only the amount of time it takes for the heating element itself to cool down below a threshold temperature. 2) The body of the tank is not yet at that temperature of the heated water, so there is a higher thermal gradient, the water cools down faster than if the rest of the tank were already warmer than it is so it will cycle on again sooner after this first heating cycle than it will on subsequent heating cycles, all else being equal (same amount of insulation and same ambient room temperature and room airflow rate, which changes in winter or summer if your furnace or fan is blowing nearby).
110100101108 years ago
sure it heats too much just try yourself how much time is needed cleaning / replacing th heating element often can cut down much the time needed there are accelerator sleeves you can install over the heating element. when you use them the tank makes the first amount of hot water way faster go solar if you have option there are electrical on the fly heaters. you install them inline with the shower. they heat the water on the fly from cold to the temperature you want. they have very high power but still save 80 - 90 % of electricity use compared to standard hot tanks - cause they are intermittent
randomhat8 years ago
The boiler clicking off typically means that the water has reached the temperature set on the boiler. You'd have to check the settings on the boiler(energy guide, etc). If the boiler kicks in frequently, it means your either using up that hot water and it has to replace it by heating more, or the temperature is set to low and the water cools off to quickly so you might want to raise the temperature.