We recently purchased an existing condominium in a six-family house that was completed in December 2014.
The building has a total enclosed volume of 3,114 cubic meters (cbm), with a total living area of just under 640 square meters (sqm). Installed is an air-to-water heat pump Stiebel Eltron WPL 33 HT with the hot water storage tank SBB 1000 Wärmepumpe SOL. The heating capacity is specified as 12.38 kW at A -7/W35 and 7.45 kW at A2/W35 partial load. I am not an expert and find these figures difficult to interpret; so far, I have found little clarifying information online.
The electricity consumption for the entire building in 2016 was extremely high at 30,360 kWh (equal to 7,650 euros). Could it be that the system was significantly undersized and therefore has to run constantly? According to the seller, the construction company had to install a slope stabilization afterwards at a six-figure cost. I wouldn’t be surprised if savings were made elsewhere...
On the Stiebel Eltron website, when selecting options for new builds over 240 sqm (about 2,583 sqft), the above-mentioned pump is not recommended. This might be an initial indication of a non-ideal configuration.
In my opinion, the rental costs for various heat meters are also disproportionately high. Is it possible to replace them with individual meters, and what would the cost be? An air-to-water heat pump is supposed to be very low-maintenance. Are maintenance costs of 672 euros reasonable?
Thank you in advance for your expert feedback.
The building has a total enclosed volume of 3,114 cubic meters (cbm), with a total living area of just under 640 square meters (sqm). Installed is an air-to-water heat pump Stiebel Eltron WPL 33 HT with the hot water storage tank SBB 1000 Wärmepumpe SOL. The heating capacity is specified as 12.38 kW at A -7/W35 and 7.45 kW at A2/W35 partial load. I am not an expert and find these figures difficult to interpret; so far, I have found little clarifying information online.
The electricity consumption for the entire building in 2016 was extremely high at 30,360 kWh (equal to 7,650 euros). Could it be that the system was significantly undersized and therefore has to run constantly? According to the seller, the construction company had to install a slope stabilization afterwards at a six-figure cost. I wouldn’t be surprised if savings were made elsewhere...
On the Stiebel Eltron website, when selecting options for new builds over 240 sqm (about 2,583 sqft), the above-mentioned pump is not recommended. This might be an initial indication of a non-ideal configuration.
In my opinion, the rental costs for various heat meters are also disproportionately high. Is it possible to replace them with individual meters, and what would the cost be? An air-to-water heat pump is supposed to be very low-maintenance. Are maintenance costs of 672 euros reasonable?
Thank you in advance for your expert feedback.
Thank you very much for these comments.
Regarding the recommended heating load calculation, I wonder
a) whether it was mandatory to carry it out during the 2012 building planning?
b) whom I should contact, the developer or the heating engineer?
c) whether those responsible are actually required to provide this calculation to me as the apartment buyer?
I tend to assume—if my suspicion of an undersized system is correct—that all parties will be uncooperative. And then? Should I hire an expert just based on suspicion, and how much would that cost? And would the homeowner association cooperate? As correctly pointed out here, the heating costs are just a pass-through item for the four landlords in the building.
Regarding the recommended heating load calculation, I wonder
a) whether it was mandatory to carry it out during the 2012 building planning?
b) whom I should contact, the developer or the heating engineer?
c) whether those responsible are actually required to provide this calculation to me as the apartment buyer?
I tend to assume—if my suspicion of an undersized system is correct—that all parties will be uncooperative. And then? Should I hire an expert just based on suspicion, and how much would that cost? And would the homeowner association cooperate? As correctly pointed out here, the heating costs are just a pass-through item for the four landlords in the building.
I would rather suggest discussing the usage habits with the other owners!
A heat pump needs to be carefully and properly adjusted, and so on.
A quick question: how warm is your domestic hot water?
What is the flow temperature at the underfloor heating directly at the heat pump?
What are the thermostat settings in the apartments?
A heat pump needs to be carefully and properly adjusted, and so on.
A quick question: how warm is your domestic hot water?
What is the flow temperature at the underfloor heating directly at the heat pump?
What are the thermostat settings in the apartments?
tomtom79 schrieb:
I would rather discuss the usage behavior with the other owners!
Well, it seems rather unlikely that all six apartment owners—four of whom are tenants—are completely indifferent to energy costs and keep their heating systems running at full power all the time. In addition, the temperature in the apartments can only be controlled via the thermostat; all other settings can probably only be adjusted directly on the heating system. According to the heating technician, these settings are correct.
Yes, of course the values on the system are correct. It does get warm. Nothing else matters to him.
And that’s the worst part.
A heating load calculation does not necessarily have to be done first. You can also estimate. But that’s just not ideal.
Heat pumps are extremely sensitive to excessively high supply temperatures as well as the required flow rate.
Personally, I suspect a complete planning failure and the resulting high operating costs.
Add improper heating behavior to that, and you have the misery.
And that’s the worst part.
A heating load calculation does not necessarily have to be done first. You can also estimate. But that’s just not ideal.
Heat pumps are extremely sensitive to excessively high supply temperatures as well as the required flow rate.
Personally, I suspect a complete planning failure and the resulting high operating costs.
Add improper heating behavior to that, and you have the misery.
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