Dear all,
I am currently facing a delivery issue with my heat pump (Vaillant Arotherm Plus VWL 75/6), which is not available from any dealer and according to the manufacturer will likely only be delivered in calendar week 6 of 2022. With winter approaching and my heating technician now using his instantaneous water heater at another customer’s place, the situation is becoming quite problematic. He is offering me a 5 kW (kilowatt) fan heater as a temporary solution, but I’m concerned that this will lead to very high energy costs.
For this reason, I have come up with the idea of getting a readily available monoblock heat pump to use just as a temporary measure until my Vaillant arrives. There seems to be a Panasonic model (probably from the series of the well-known and widely recommended “Geisha”) which appears to be suitable and is available at a reasonable price (around 3500 EUR). I would then resell it afterwards.
However, since the market for used heat pumps is rather small, I wonder whether this will really be cheaper than heating electrically with direct heating for three months. I have roughly calculated that in the worst case, I would have to expect heating costs of 2500-3000 EUR with electric direct heating (depending on extent and weather conditions).
Does anyone here have experience with this?
@Benutzer200, if I remember correctly, you once installed a Panasonic unit? Did you happen to sell it later on?
Well, I hope someone has faced a similar problem and can share their experience.
Kind regards
Tolentino
I am currently facing a delivery issue with my heat pump (Vaillant Arotherm Plus VWL 75/6), which is not available from any dealer and according to the manufacturer will likely only be delivered in calendar week 6 of 2022. With winter approaching and my heating technician now using his instantaneous water heater at another customer’s place, the situation is becoming quite problematic. He is offering me a 5 kW (kilowatt) fan heater as a temporary solution, but I’m concerned that this will lead to very high energy costs.
For this reason, I have come up with the idea of getting a readily available monoblock heat pump to use just as a temporary measure until my Vaillant arrives. There seems to be a Panasonic model (probably from the series of the well-known and widely recommended “Geisha”) which appears to be suitable and is available at a reasonable price (around 3500 EUR). I would then resell it afterwards.
However, since the market for used heat pumps is rather small, I wonder whether this will really be cheaper than heating electrically with direct heating for three months. I have roughly calculated that in the worst case, I would have to expect heating costs of 2500-3000 EUR with electric direct heating (depending on extent and weather conditions).
Does anyone here have experience with this?
@Benutzer200, if I remember correctly, you once installed a Panasonic unit? Did you happen to sell it later on?
Well, I hope someone has faced a similar problem and can share their experience.
Kind regards
Tolentino
R
RotorMotor4 Mar 2022 11:24tomtom79 schrieb:
There is still a lot you haven’t heard, but if there is one thing I’ve learned in 7 years of working with heat pumps, it’s about their basic settings. Of course, each one has its own characteristics and adjustment options, but a heat pump needs to run through cycles. That means running a low heating curve, disabling night setback, and so on. Many factors play a role, of course, but there are fundamental rules.Please don’t take this personally, but both statements only make limited sense.The heating curve is adjusted based on the heating demand.
Sure, turning it down will reduce electricity consumption, but what’s the point if it gets cold inside?!
Night setback often makes sense because it allows the use of photovoltaic energy, and the air-to-water heat pump then doesn’t have to produce a high flow temperature during the coldest periods.
I want to have a nicely warm bath in the morning, not just “okay warm.” It’s all just hindsight. Now we have sun again, which we didn’t have all winter. Running it efficiently without shutting off or increasing the temperature is affordable and no one complains.
Of course, I would also like to use my photovoltaic system during the day for this. But I still want to enjoy a nicely warm bath in the morning.
It’s like electric car drivers turning off the heating to increase their range. I had to do that once just to make it home. I never want to do that again. I’m not going to give up the comfort I paid a lot for just to save $50 on electricity.
Of course, I would also like to use my photovoltaic system during the day for this. But I still want to enjoy a nicely warm bath in the morning.
It’s like electric car drivers turning off the heating to increase their range. I had to do that once just to make it home. I never want to do that again. I’m not going to give up the comfort I paid a lot for just to save $50 on electricity.
RotorMotor schrieb:
Please don’t take this the wrong way, but both statements don’t really make much sense.
The heating curve is set based on the heating demand.
Sure, simply turning it down would reduce electricity consumption, but what’s the point if it gets cold then?!
Night setback often makes sense because it allows you to use photovoltaic energy, and the air-to-water heat pump doesn’t have to provide a high supply temperature during the coldest conditions. I don’t feel attacked at all.
To clarify, you have a daily consumption around 30 kW, right? And the heat pump should be a modulating type? So something throttles back, the room cools down, and the heat pump has to catch up with a higher heating curve. Unfortunately, the higher heating curve does not correspond linearly to consumption; efficiency decreases.
So, perform hydraulic balancing while it’s still around 0°C (32°F) outside, find the coldest room, and then, during the day, overheat the screed.
R
RotorMotor4 Mar 2022 12:14OWLer schrieb:
But in the morning, I want a nicely warm bathroom, not just “OK warm.” It’s all just hypothetical. Now we have sun again. None all winter. Running it efficiently without shutting off or raising the temperature is cheap, and nobody complains. I can definitely understand that!
But people always say that underfloor heating is very slow to respond.
Have you measured how much the temperature in your bathroom would really drop in the morning with a nighttime setback of, for example, 2 degrees Celsius (3.6°F)?
But yes, you don’t want to over-optimize if it means losing comfort!
tomtom79 schrieb:
Just to clarify, you have about 30 kW consumption per day... and your heat pump should be a modulating one, right? So something is throttling, the room cools down, and the heat pump has to catch up with a higher heating curve. The higher heating curve unfortunately is not linearly related to consumption because efficiency decreases. As I said, the heating curve is adjusted depending on the energy demand.
So, it mainly depends on how well insulated and sealed the house is.
Ah, but maybe there’s confusion here caused by active bypass valves.
In my case, they are all open, of course. ;-)
Our energy demand is high simply because windows are frequently opened to remove moisture.
B
Benutzer2004 Mar 2022 13:28guckuck2 schrieb:
I would like to disagree with that. An indoor temperature-based heating system is more efficient, or at least the indoor temperature should be taken into account when determining the required supply temperature. This significantly increases efficiency, especially during transitional seasons, because in a new building the heating can simply stay off when it’s cold outside but still warm inside, and solar gains may occur during the day. The heating also stays off during the day when using only the heating curve. This is how I have been operating for many years (with a ground-source heat pump and now with an air-to-water heat pump). The heating system detects from the return temperature—which remains warm since the building is still heated—that no output is needed. Currently, the heating is off between 11 a.m. and 5 p.m.—even in an older building 😉 . So, in essence, the result is the same, but achieved in a different way.
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