We have moved into our new build and noticed that it takes quite a long time for hot water to be available.
It feels like I use about 3 liters (1 US quart) and wait 30 seconds or more before the water starts to get warm.
We do not have a circulation pump, and this was not offered to us beforehand. Therefore, installing one now is not an option.
Our developer generally says that circulation pumps are not necessary in single-family homes.
What is your experience with this?
It feels like I use about 3 liters (1 US quart) and wait 30 seconds or more before the water starts to get warm.
We do not have a circulation pump, and this was not offered to us beforehand. Therefore, installing one now is not an option.
Our developer generally says that circulation pumps are not necessary in single-family homes.
What is your experience with this?
D
daniels877 Mar 2017 18:50I have planned a small regulated tankless water heater for the washbasins upstairs, which heats the water until it reaches the desired warm temperature. Currently, it takes a long time for warm water to arrive at our taps because they are adjusted for low flow.
B
Baustelle20167 Mar 2017 18:52We have a circulation pump in our single-family house, controlled by a timer. When it is on, warm water arrives in about 5 seconds, and when it is off, it takes around 25 seconds. Since water is cheap, the operation of the pump probably costs more than the additional consumption of water (and gas) without a circulation pump. Otherwise, why would it be operated with a timer, I suppose. But what exactly is your question aiming at? Do you want to avoid waiting so long for warm water? I’m afraid that making improvements in this regard is difficult or economically impractical.
so the theoretical regulation states:
However, since it is practically impossible to reach 60°C (140°F) at the faucet, there are other regulations.
VDI 6003 differentiates between requirement levels, which actually refer to flow rate per minute. For example, a shower with a flow rate of 7 liters per minute (7l/min) must reach 42°C (108°F) after 7 seconds, whereas a kitchen sink with a flow rate of 6 liters per minute (6l/min) must reach 50°C (122°F) within 10 seconds. If the mixer tap allows less flow, the allowed time increases.
If this takes significantly longer, it is basically a defect. Plumbers often use pipes that are too large, so a much larger volume of water has to flow through before warm water finally arrives.
In our case, they had to fix it because the DIN and VDI standards are very clear about this. It was relatively simple for us since we already had a circulation pump (though only for the upper floor), and in the kitchen, warm water finally arrived after 25 seconds and 3.5 liters, corresponding to requirement level 3 (6l/min or more), kitchen at 10 seconds and 50°C (122°F).
Now all hot water outlets in our house are connected to the circulation system, and I think it’s great. Waiting for warm water is annoying, uncomfortable, and not cost-effective. The pump’s electricity usage also costs money, but it’s only a few cents. Such a pump consumes about 5–10 watts and can be controlled by a timer to run during the hours of the day when warm water is typically needed (around 2 hours during common showering and cooking times). In our case, the pump runs about 5 hours daily, consuming about 1.5 kWh (10 watts), which costs roughly 50 cents per month. However, I save around 30 times 5 liters (almost 50 cents at a water price including sewage of €4.70 per 1,000 liters) during showers. Plus, I save 25 seconds every morning before I can start showering without hassle.
By the way, a hot water circulation system can also be retrofitted. If you have the hot water pipe plans of your house, post them here and I can take a look. For us, the circulation installation in the basement was completed within 2 hours. Only one wall had to be opened in the utility room, where a pipe was tapped and extended.
In our shower, warm water comes out after 1 second. I turn it on and immediately step in. The standing water in the pipe behind the mixer tap, of course, has to flush out first.
European Standard
In the DIN EN 806-2 “Technical rules for drinking water installations – Part 2: planning,” published in June 2005, it says that 30 seconds after fully opening a cold water outlet, the water temperature should not exceed 25°C (77°F). For hot water outlets, it should not be less than 60°C (140°F).
However, since it is practically impossible to reach 60°C (140°F) at the faucet, there are other regulations.
VDI 6003 differentiates between requirement levels, which actually refer to flow rate per minute. For example, a shower with a flow rate of 7 liters per minute (7l/min) must reach 42°C (108°F) after 7 seconds, whereas a kitchen sink with a flow rate of 6 liters per minute (6l/min) must reach 50°C (122°F) within 10 seconds. If the mixer tap allows less flow, the allowed time increases.
If this takes significantly longer, it is basically a defect. Plumbers often use pipes that are too large, so a much larger volume of water has to flow through before warm water finally arrives.
In our case, they had to fix it because the DIN and VDI standards are very clear about this. It was relatively simple for us since we already had a circulation pump (though only for the upper floor), and in the kitchen, warm water finally arrived after 25 seconds and 3.5 liters, corresponding to requirement level 3 (6l/min or more), kitchen at 10 seconds and 50°C (122°F).
Now all hot water outlets in our house are connected to the circulation system, and I think it’s great. Waiting for warm water is annoying, uncomfortable, and not cost-effective. The pump’s electricity usage also costs money, but it’s only a few cents. Such a pump consumes about 5–10 watts and can be controlled by a timer to run during the hours of the day when warm water is typically needed (around 2 hours during common showering and cooking times). In our case, the pump runs about 5 hours daily, consuming about 1.5 kWh (10 watts), which costs roughly 50 cents per month. However, I save around 30 times 5 liters (almost 50 cents at a water price including sewage of €4.70 per 1,000 liters) during showers. Plus, I save 25 seconds every morning before I can start showering without hassle.
By the way, a hot water circulation system can also be retrofitted. If you have the hot water pipe plans of your house, post them here and I can take a look. For us, the circulation installation in the basement was completed within 2 hours. Only one wall had to be opened in the utility room, where a pipe was tapped and extended.
In our shower, warm water comes out after 1 second. I turn it on and immediately step in. The standing water in the pipe behind the mixer tap, of course, has to flush out first.
Baustelle2016 schrieb:
Why else would it be operated with a timer... I suppose.That is just one of many operating modes.
A circulation pump should be able to learn, so that, for example, hot water is ready by 7 a.m. and turned off for the rest of the day.
Or continuous operation so that hot water is available within a maximum of 5-10 seconds, and so on...
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