I am currently looking for new faucets, starting with the bathroom. Right now, there is a common single-lever mixer, but in our case, the water is either hot/warm or cold and should not be mixed—or it would be pointless.
Is there another solution besides having two cold water taps connected separately to the respective pipes, since washbasins usually only have one hole?
Basically something like the old-style taps with turn knobs on the left and right, but without the turning handles. Maybe with push buttons?
It should be a bit modern. Also, you don’t want to have to turn the taps for ages until the strongest flow finally comes out.
I have also thought about sensor faucets, but I’m bothered by the batteries.
Somehow, I am missing the right term to search for (searching for “two-temperature faucet” or “faucet without mixer” returns no results).
Is there another solution besides having two cold water taps connected separately to the respective pipes, since washbasins usually only have one hole?
Basically something like the old-style taps with turn knobs on the left and right, but without the turning handles. Maybe with push buttons?
It should be a bit modern. Also, you don’t want to have to turn the taps for ages until the strongest flow finally comes out.
I have also thought about sensor faucets, but I’m bothered by the batteries.
Somehow, I am missing the right term to search for (searching for “two-temperature faucet” or “faucet without mixer” returns no results).
Sir_Kermit24 Jul 2016 20:17Hello,
That is precisely the advantage of fully electronic direct electric (DE) systems; they can regulate their output almost continuously, whereas hydraulic systems can only switch the three heating cartridges on or off.
Kermit
sent from tablet
That is precisely the advantage of fully electronic direct electric (DE) systems; they can regulate their output almost continuously, whereas hydraulic systems can only switch the three heating cartridges on or off.
Kermit
sent from tablet
I looked up an expensive domestic hot water heat pump by Stiebel Eltron for calculation purposes. The technical data for the cheapest heat pump (unfortunately also the one with significantly the worst performance factor; there are probably better suppliers, but it’s better to calculate conservatively) are as follows:
200-liter (53-gallon) hot water storage tank, performance factor about 3.5, cost €2000, with a standby heat loss of about 1 kWh of thermal energy (not to be confused with electrical energy) per day if the hot water is not heated to the maximum.
(If you can use photovoltaic energy to increase the temperature, this becomes less relevant.)
This results in the following annual cost for electricity, with electricity cost X and annual hot water energy demand Y:
X * ((Y + 365) / 3.5)
In contrast, an electric instantaneous water heater simply tries to cover costs of:
X * Y
The difference between these two costs shows how much cheaper or more expensive the heat pump is compared to the instantaneous water heater:
X * Y - X * ((Y + 365) / 3.5)
If the result is positive, heating with the heat pump is cheaper (the number indicates how much per year). This calculation does not take into account specifics such as piping or other losses, or the efficiency of the instantaneous water heater (which can be less than 1 during short operation), which might partly balance out.
Example: X = 0.2 (20 cents electricity cost), Y = 600 (kWh hot water demand)
0.2 * 600 - 0.2 * ((600 + 365)/3.5) = 120 - 55.14 = 65 €.
So you save 65 € per year but have to invest 2000 €. In this example, it would not be cost-effective. However, if you find a cheaper heat pump or have higher demand, the situation can be very different.
Incidentally, you can apply the same calculation with a gas boiler, since the cost per kWh ratio is comparable to that of a heat pump.
200-liter (53-gallon) hot water storage tank, performance factor about 3.5, cost €2000, with a standby heat loss of about 1 kWh of thermal energy (not to be confused with electrical energy) per day if the hot water is not heated to the maximum.
(If you can use photovoltaic energy to increase the temperature, this becomes less relevant.)
This results in the following annual cost for electricity, with electricity cost X and annual hot water energy demand Y:
X * ((Y + 365) / 3.5)
In contrast, an electric instantaneous water heater simply tries to cover costs of:
X * Y
The difference between these two costs shows how much cheaper or more expensive the heat pump is compared to the instantaneous water heater:
X * Y - X * ((Y + 365) / 3.5)
If the result is positive, heating with the heat pump is cheaper (the number indicates how much per year). This calculation does not take into account specifics such as piping or other losses, or the efficiency of the instantaneous water heater (which can be less than 1 during short operation), which might partly balance out.
Example: X = 0.2 (20 cents electricity cost), Y = 600 (kWh hot water demand)
0.2 * 600 - 0.2 * ((600 + 365)/3.5) = 120 - 55.14 = 65 €.
So you save 65 € per year but have to invest 2000 €. In this example, it would not be cost-effective. However, if you find a cheaper heat pump or have higher demand, the situation can be very different.
Incidentally, you can apply the same calculation with a gas boiler, since the cost per kWh ratio is comparable to that of a heat pump.
D
daniels8725 Jul 2016 08:38Elina schrieb:
If you don’t turn the tap fully on (hot), no hot water comes out at all because the instantaneous water heater doesn’t activate. Although it’s an electronic one, not a hydraulic type, it still requires a minimum flow rate to switch on.Then you could just use a cold water tap.
My faucet is a no-name brand, so I don’t know if this system exists with branded faucets as well. I really like it because you always open the cold water first automatically, and only when you turn the handle all the way does hot water come out. With faucets that have the handle, for example, on top, you usually set it to a middle position. This means you often get lukewarm water, even though most of the time you don’t need it.
P
Peanuts7425 Jul 2016 12:06Elina schrieb:
I think it really depends on how much water the storage tank can hold and how much hot water is used daily. You can’t really specify something like 20 days across the board.
It makes perfect sense that an instant water heater is more worthwhile the less hot water you need. For us, with 2 people and only showers, plus a total water consumption (hot and cold) of 33 cubic meters (11,650 cubic feet) per year, the instant water heater definitely makes sense. Breaking it down, we use 90 liters (24 gallons) of water per day for 2 people, including cold water.
Compared to our rented apartment, it’s probably about the same, although back then we were also paying for the neighbors’ hot water. So operating costs are similar; it’s just a question whether a new installation is worthwhile. A hot water heat pump would cost around 700 euros, which is hard to recoup. The only advantage would be charging it during the day via photovoltaics, making the electricity cost only about 10 euro cents (10 cents) per kWh. Here, showers are mostly taken at night and midday, widely spaced, so I don’t expect any problems with storage capacity.
Basically, we also thought we’d definitely need the heat pump for the KfW 100 certification instead of the instant water heater, but that wasn’t the case because the share of renewable energy from the pellet boiler alone already easily exceeds the requirement.How can you manage with 45 liters (12 gallons) per day per person including everything???
Just when someone takes a shower here, 150 liters (40 gallons) goes through (which admittedly is because of the Raindance showerhead and very relaxed showering).
Still, if everyone flushes the toilet 5 times a day, that’s likely 30–40 liters (8–11 gallons) even with a dual-flush system.
Plus washing machine, dishwasher, cooking, etc...
Sure, if the meter only shows 33 cubic meters (11,650 cubic feet), it might add up, but how exactly, I wonder...
Besides, I don’t always shower at the same temperature, and it’s easier to adjust the temperature using the shower mixer than to get in and think, oh no, today it’s too cool, hmm no, too warm after all.
So I see it more as a gimmick rather than a genuine saving effect...
Sir_Kermit25 Jul 2016 12:20Hello,
That’s not showering, that’s dissolving ... For showering, you usually calculate roughly 40 liters (10.5 gallons).
Kermit
Peanuts74 schrieb:
Just when Madama showers, 150L (40 gallons) flow through here (which admittedly is due to the Raindance showerhead and very relaxed showering).
That’s not showering, that’s dissolving ... For showering, you usually calculate roughly 40 liters (10.5 gallons).
Kermit
P
Peanuts7425 Jul 2016 12:32As I said before, this is partly due to the Raindance showerhead, which allows 18 L/min (4.8 gal/min) and results in very long showers. But even with 2 x 40 L (2 x 10.6 gal), there are still 10 L (2.6 gal) left for cooking, dishwashing, laundry, and flushing—for both of them!!!
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