Gas meter or gas heater defective?

Hello,

I am a bit speechless right now.
My parents received a gas back payment of €3,300.
I have checked, since January they are supposed to have consumed 1,500m³ of gas or about 13,500 kWh converted.
They did not have that earlier in the year. The new advance payments are supposed to increase from €100 to €600. :oops:

Nothing has changed in the settings.
The heating system (heating and house from 1999) has repeatedly broken down over the last few years (pipes were flushed a few times, "spark plug" replaced).

Is it possible that the meter is defective? It runs extremely fast when the heating is on.
How can I best / fastest have the meter checked?

Or can a defective heating system consume much more gas?

Thanks in advance!

First, check the bills from previous years to see if there was a reading error.

Then check if, due to the gas.de bankruptcy, you have not been moved to a basic tariff.

How old is the meter and when was it calibrated?

Hello,

I agree with the previous speaker! Otherwise, for the future, read and note the meter every 1-2 months. Then you have approximate values and notice something like this early on.