ᐅ Single-family house – 18,000 kWh in two years – what could be the issue?

tomtom79 schrieb:

@superzapp erzapp How do you come up with these numbers?

19000 in 2 years, 9500 kWh / 2 residential units, that’s 4500 kWh including heating per household. Without knowing the exact square meters, that seems okay.

@titoz
Regarding your problem, you first need to separate the two apartments, which an electrician will do. Then they will apply for the second meter.

For the heat pump, you need a heat meter at the transfer point to the secondary apartment for billing heating and hot water.

We do not have a second meter from the energy supplier but an own calibrated meter to measure electricity usage for the secondary apartment. However, electricity for hot water, cooling, ventilation, and heating is not included in that.

We have a heat meter on the return line of the heating system for the secondary apartment. Since the tenants moved in, the meter reading increased from 7.237 MWh to 13.090 MWh. But I wasn’t provided with a heat meter for hot water. So that means the tenant used 5.853 MWh for heating. But what if cooling is done through the same system? How would the heat meter register that?

I also have a heat meter inside the heat pump:
Heating, compressor only: 28,642 kWh
Domestic hot water, compressor only: 7,045 kWh
Heat including internal auxiliary heating: 45,637 kWh
Domestic hot water including internal auxiliary heating: 7,873 kWh
BF1: 18.4 liters/min (4.9 gallons/min)

But these values are probably cumulative since commissioning in 2017.

Guys, you have no idea how frustrating this is for me. I’ll be glad once everything in and around the house has settled and I know how everything works and is supposed to operate.

Some time ago, I spoke with my former builder, and he suggested the following method for billing:

Electricity for general use: The granny flat has its own meter.
Heating/Cooling/Hot water: Electricity costs of the heat pump are divided based on the number of occupants (4 in the main house / 3 in the granny flat = 43% of the costs charged to the granny flat) or by living area (approximately 125m² (1345 sq ft) / 75m² (807 sq ft) = 38% of the costs for the granny flat).
Cold water: Water and wastewater costs are allocated per person.

Could this approach work?
It wouldn’t be exact, but it would be simple.

Bookstar schrieb:

Typical problem: the heat pump consumes a lot of energy. Almost all owners know this... the only solution is proper balancing and adjustment.

Who can help with the balancing and adjustment?

My builder initially set different settings than the Nibe service technician.

According to the builder, Nibe knows a lot about heat pumps but not about "mass concrete heating," so some of Nibe’s settings were not suitable.

I know I understood it, so I will call an electrician to separate both apartments and then apply for a second meter.
It was just calculated, and that seems fine so far.

But 45,000 kWh of heat energy is a lot; I haven’t reached that even after 5 years with 250m² (2,690 sq ft).

Okay, let's summarize:

How large are the heated areas?

What temperature is the domestic hot water set to?

How big is the hot water storage tank?

What is the supply temperature?

Take a look at the heating cost regulation. Normally, heating costs must be metered. However, I’m not sure if there are any special rules for a granny flat. You can charge all other additional costs as you wish (by area, number of occupants, consumption, etc.).

titoz schrieb:

Some time ago, I spoke with my then developer, and he said he would bill it like this:

Utility electricity: The separate apartment has its own meter.
Heating/cooling/hot water: Electricity costs for the heat pump are divided based on the number of occupants (4 in the main house / 3 in the separate apartment = 43% of the costs assigned to the separate apartment) or by living area (approx. 125m² (1345 sq ft) / 75m² (807 sq ft) = 38% of the costs for the separate apartment).
Cold water: Costs for water and wastewater are divided by number of occupants.

Could this work?
It wouldn’t be exact, but it would be simple.

We calculated it the same way for the authorities, but that’s my mother-in-law. If she uses a few extra kilowatt hours, it doesn’t matter; the value of her supporting us makes it worth it. But with strangers, believe me, they don’t care whether the heating is turned up and the window is open, roughly speaking.