ᐅ Long wait time for hot water to arrive

I would never build without a circulation pump. I didn’t even know those were still available. Ours is adaptive and costs about 12 euros per year in electricity, easily saving that amount in water. Not to mention the comfort.

Yes, plus additional effort during installation and material costs. It's basically a comfort feature. But the original poster has already decided against it. The only possibility would probably be a small electric tankless water heater.

We have a circulation pump and are very satisfied with it. Our pump is off from 11:00 PM to 6:00 AM. Between 6:00 AM and 11:00 PM, it is on when someone is present (detected via smartphones connected to the Wi-Fi → controlled by KNX).

As a retrofitting option, I only see a small tankless water heater.

Possibly a bit off-topic:
Regarding the costs of circulation pumps, I have read that electricity is relatively cheap (assumed €12/year as mentioned by [USER=28865]@77.willo). However, the hidden costs seem to lie in the hot water preparation for this loop, which should be many times higher (depending on the system used). I hope the experts here in the forum can confirm or refute this?

Good luck

ntsa86 schrieb:
I hope the experts here in the forum can confirm or debunk this?

Good luck

I’m not an expert, but:
- The few meters of pipe probably release less energy through the insulation than an equally long section of the underfloor heating pipe, even if the latter is cooler. You might have around 25 meters (80 feet) of the main circulation pipe in the house, but the underfloor heating pipes are more likely to run hundreds of meters (feet).
- The energy stays inside the house, so it’s not necessarily lost (except in summer).

Well, I can’t imagine building without circulation either. We also have a dishwasher and washing machine connected to hot water, which alone made it worthwhile, not to mention the comfort when showering.

The correct point is that the circulation system also loses heat in the pipes. However, from the perspective of the building’s sealed envelope (house), the heat is not lost but may potentially warm other rooms as well (theoretically).
To put it briefly: cost-wise, it is more or less neutral with slight disadvantages. It is more a matter of comfort. In the end, the expense is not significantly high but does provide some benefit.

If the new building has just been approved, it is still possible to create a defect report based on the mentioned DIN/VDI standards and demand fulfillment. In our case, discussions had already taken place with the tilers from the sanitation contractor because they wanted to break up the entire hallway. The regulations are not there without reason. A delay of 25 seconds until warm water arrives is simply poor planning or execution and therefore a defect. Either the pipe was not installed as the planner calculated, the pipe diameter is too large, or the planning was already incorrect—in the best case, there was no planning of the hot water pipe at all.

Always remember: you are building a modern house and, for example, can never get warm water from the kitchen tap when you only need 2–3 liters (0.5–0.8 gallons) for the pot, but warm water only arrives after 4 liters (1 gallon) have run. That is completely ridiculous...

With minimized pipe lengths and optimal pipe diameters, a circulation pump is usually not necessary. Ideally, the bathrooms are located directly above the boiler room, so 5-6 meters (16-20 feet) of water piping is sufficient. Using the pipe diameter and flow rate, everyone can calculate how long they will have to wait for hot water.