Hello.
I am planning to install a Vaillant ground source heat pump VWF 88/4.
We are considering installing a second electricity meter to benefit from a cheaper tariff for the heat pump.
However, this meter would be off for up to 6 hours per day.
As far as I know, we do not have a buffer tank integrated.
Alternatively, we could use the regular electricity supply (one meter). Overall, this would cost about €250-300 per year more than with the heat pump tariff.
I am concerned that during the off periods, the electric heating element might turn on, and we could end up spending much more than the €250-300 savings.
How does the electric heating element usually work – does it only activate in emergencies, or does it always come on when hot water is drawn?
I would appreciate any answers or experiences.
I am planning to install a Vaillant ground source heat pump VWF 88/4.
We are considering installing a second electricity meter to benefit from a cheaper tariff for the heat pump.
However, this meter would be off for up to 6 hours per day.
As far as I know, we do not have a buffer tank integrated.
Alternatively, we could use the regular electricity supply (one meter). Overall, this would cost about €250-300 per year more than with the heat pump tariff.
I am concerned that during the off periods, the electric heating element might turn on, and we could end up spending much more than the €250-300 savings.
How does the electric heating element usually work – does it only activate in emergencies, or does it always come on when hot water is drawn?
I would appreciate any answers or experiences.
The blackout period is, for example, split in our case, and we haven’t noticed any issues so far. We have a 300-liter (79-gallon) hot water tank.
The blackout period is, I believe, between 8:30–9:30 and in the evening between 17:30–18:30. During these times, hot water is rarely needed, and the house certainly doesn’t cool down.
Currently, with 200 m² (2,150 sq ft) and a winter temperature always at least 23°C (73°F), we are at 2,900 kWh over 10 months in this KfW 70 house. I think that’s quite impressive. We live at around 500 meters (1,640 feet) above sea level, which means about 30 days of snow in the Black Forest.
Heat pumps have a lot of adjustment potential. For example, we recently set a shutoff so that the underfloor heating fully switches off if the temperature is above 18°C (64°F) for two consecutive days. Before, it was running “all the time.”
Hot water setpoint of 45°C (113°F) is sufficient; it was previously set to 50 or 55°C (122 or 131°F).
The blackout period is, I believe, between 8:30–9:30 and in the evening between 17:30–18:30. During these times, hot water is rarely needed, and the house certainly doesn’t cool down.
Currently, with 200 m² (2,150 sq ft) and a winter temperature always at least 23°C (73°F), we are at 2,900 kWh over 10 months in this KfW 70 house. I think that’s quite impressive. We live at around 500 meters (1,640 feet) above sea level, which means about 30 days of snow in the Black Forest.
Heat pumps have a lot of adjustment potential. For example, we recently set a shutoff so that the underfloor heating fully switches off if the temperature is above 18°C (64°F) for two consecutive days. Before, it was running “all the time.”
Hot water setpoint of 45°C (113°F) is sufficient; it was previously set to 50 or 55°C (122 or 131°F).
We are currently finishing our second heating year.
Our house is 170 sqm (1,830 sq ft) and built to KfW70 standard according to the 2009 Energy Saving Ordinance (2014 version).
For this billing year, we expect to use about 3,300 kWh for the heat pump (heating and hot water) – the last 1.5 months are estimated. We currently pay 18.99 cents per kWh (no basic fee). Our Vaillant system has a 170 liter (45 gallon) tank, which usually meets our needs well.
Altogether (from the start until now), we have just exceeded 8,000 kWh consumption (including the initial heating-up phase).
Therefore, I also think your estimates are too high. However, our energy consultant predicted 8,000 kWh consumption for the first year as well.
Our house is 170 sqm (1,830 sq ft) and built to KfW70 standard according to the 2009 Energy Saving Ordinance (2014 version).
For this billing year, we expect to use about 3,300 kWh for the heat pump (heating and hot water) – the last 1.5 months are estimated. We currently pay 18.99 cents per kWh (no basic fee). Our Vaillant system has a 170 liter (45 gallon) tank, which usually meets our needs well.
Altogether (from the start until now), we have just exceeded 8,000 kWh consumption (including the initial heating-up phase).
Therefore, I also think your estimates are too high. However, our energy consultant predicted 8,000 kWh consumption for the first year as well.
toxicmolotow schrieb:
Note: What the grid operator allows does not matter. There are low-cost electricity suppliers that prohibit this regardless of the grid operator!Do you know why, what the background is, and how this can be monitored?
So far, I have not found any electricity supplier in the area whose heat pump electricity tariffs even come close to compensating for the additional costs of the extra meter. This is compared to low-cost suppliers identified through comparison platforms.
T
toxicmolotof12 Aug 2016 15:18This developed "historically."
Many suppliers prohibit the use of household electricity for "heating purposes." Back then, this included electric storage heaters that consumed far more energy than modern heat pumps, which use no more power than an oven and a hairdryer. Nonetheless, it remains electricity used for heating purposes.
Regarding enforceability: a contract is a contract, and anyone who violates it falls back into the basic supply. Quite clear. All that is needed is a verification reading, and next to the meter is a heat pump. It might work out, or it might not. It's like speeding—there aren’t speed cameras everywhere.
As for the payback period with maybe 2,000 kWh (2,140 kWh), I completely agree with you.
Many suppliers prohibit the use of household electricity for "heating purposes." Back then, this included electric storage heaters that consumed far more energy than modern heat pumps, which use no more power than an oven and a hairdryer. Nonetheless, it remains electricity used for heating purposes.
Regarding enforceability: a contract is a contract, and anyone who violates it falls back into the basic supply. Quite clear. All that is needed is a verification reading, and next to the meter is a heat pump. It might work out, or it might not. It's like speeding—there aren’t speed cameras everywhere.
As for the payback period with maybe 2,000 kWh (2,140 kWh), I completely agree with you.
Similar topics