ᐅ Air-to-Water Heat Pump: Current Consumption and Data

Benutzer200 schrieb:

120 sqm (1,292 sq ft) older building from the mid-1960s – (still) no external thermal insulation composite system (ETICS), but the upper floor and basement ceiling are insulated. 75% of the windows are new.
Current energy consumption at around 22°C (72°F) indoor temperature is about 8 kWh including hot water, with nighttime temperatures of 3-4°C (37-39°F) and daytime temperatures of 7-9°C (45-48°F).

By the way, I don’t use any energy recovery ventilation (ERV) or actuators.

Hello everyone 🙂,

I’m new to the forum, but I have been reading for some time to better understand my new heat pump heating system.
Since summer, we have also been using a heat pump to replace our old oil boiler. We are using it to heat our renovated and insulated old building. The energy consultant calculated a heating load of 11 kW (approx. KfW 60) for our house, and based on that, we chose (or rather, the builder recommended) the Vaillant Arotherm plus 125 A /S2. I am currently using the consumption and energy yield data recorded by the system. We do not (yet) have a dedicated heat meter or a separate electricity meter. We have exclusively underfloor heating. For hot water, we have a 300 L (79 gallon) storage tank and for heating, a 200 L (53 gallon) buffer tank. The system is running as expected and the house (176 m2 (1894 sq ft)) is as warm as desired (20-21°C (68-70°F)). Of course, the real test will be in winter.

Here are the system data for October.

As of 31.10.21; heating curve 0.6; flow temperature currently 28-37°C (82-99°F); domestic hot water 45°C (113°F)

702.6 heating energy yield / month in kWh
4.0 heating seasonal performance factor / month
225 electricity consumption / month in kWh
967 total heating energy yield in kWh
3.9 total heating seasonal performance factor
145.8 domestic hot water energy yield / month in kWh
2.5 domestic hot water seasonal performance factor / month
93 electricity consumption / month in kWh
459 total domestic hot water energy yield in kWh
2.7 total domestic hot water seasonal performance factor

Greetings from Bergisches Land

This is already very good for operation with underfloor heating.

OWLer schrieb:

By now, all rooms are almost at the desired temperature with these outside temperatures between 4-7°C (39-45°F). The WEK downstairs is still a bit too warm. But that doesn’t bother us since our loft door to the hallway/stairwell is still missing. Soon I can start turning off the actuators. Then there will be no more risks related to the bypass valve.

The heat pump ran perfectly the day before yesterday.

Today it was a bit warmer, and it is now cycling once per hour again.

This will still be a long journey. 🙂

That is absolutely normal for the transitional period.
Maybe you have the option to adjust the compressor output in the lower modulation range. With my heat pump, I can adjust the compressor output just like the heating curve. Of course, this is only possible in the technician settings.

A somewhat silly question. I have now set the hot water to Eco mode so that the heat pump runs at a reduced capacity. The reason is that the heat pump is otherwise too loud for me when running at nearly 100% power. Unfortunately, there are no efficiency charts available across the modulation range. I would have assumed that the efficiency at 100%, with the high lift for hot water, is not optimal.

I’ll join in on this question as well. I also think the heat pump doesn’t need to produce domestic hot water at nearly 100% efficiency. What are the pros and cons of Eco?