Questions and answers

Do you have an administrative question or a technical question? First of all, see if it is listed below.

If this is not the case, please call our customer service department at 085 – 004 43 76.

For general enquiries, please email to For technical questions, please email us at

We will respond to your question as soon as possible.

Administrative questions

Can I get a contract for electricity at Warm Kop Grasweg as well?
No, unfortunately this is not possible. Warm Kop Grasweg only provides sustainable heat supply and not electricity supply.
What are the tariffs?
The rates can be found on the rates page..
What do the items on my year-end statement mean?
De maximale tarieven worden jaarlijks vastgesteld door de Autoriteit Consument & Markt. Hierbij een uitleg over de tarievenposten van 2024:
  • Warmth: the rental of the delivery set. The delivery set is the installation needed to bring the hot water from the hot cold storage system safely to the indoor installation for space heating and/or domestic hot water preparation.
  • Domestic hot water comfort 10 l/min: the availability of 10 liters of hot water per minute. This means that there will be enough hot water for a rain shower or the possibility of having hot water available simultaneously in the kitchen and the bathroom.
  • Heat exchanger: heats the cold drinking water that flows to the hot water taps in the kitchen or bathroom. This is done via a separate system. As a result, the drinking water does not come into contact with the hot water from the WKO system.
  • Measuring rate: costs for measuring your heat consumption. This is achieved by measuring the inflow and outflow of heat in your home with a calibrated meter. The difference is the heat output measured in m³ (hot water) or GJ (heat).
  • Cold: fixed fee for the provision of cooling.
What are the features of the customer portal?
In the customer portal, you can update your personal data, view your consumption, view invoices and change your deposit amount.
I want to change my deposit amount or something else. How do I do this?
Through the customer portal, you can easily adjust your advance. You do this via Settings, Advance, Change. From the next billing moment, the chosen advance amount will take effect. Of course, you can also contact our customer service by calling 085 - 004 43 76.
I want to change my payment method. How do I do that?
You can easily change your payment method via the customer portal. You can do this via Settings, Data, Change. You have the option of paying by direct debit or iDEAL. If you choose iDEAL, you will receive a monthly e-mail with the invoice. You can also transfer the amount to us monthly.
I'm a new resident. How can I register?
You can submit your application to us online by filling out the form on the registration page.
I'm moving soon. What should I arrange?
You can notify us of your move online by completing the form on the move out page.
A family member/acquaintance has passed away. What do I need to arrange?
Our customer service representatives will be happy to help you by calling 085 - 130 48 29.
  • Will the property stay within the family (for now)? Then the new owner can register one the page sign up.
  • If the lease is terminated or the house is sold, you can fill out the form on the page move out. Under Who fills out this form? choose I am filling out the form for a deceased family member/acquaintance.
Can I pass on my own meter readings?
You do not have to pass on your meter readings to us. We can digitally read your energy meter from a distance. You can also find the readings and your consumption on a monthly basis in the customer portal. Only the starting meter reading on moving in (for the Supply Agreement) and the ending meter reading on moving out (for the Moving Out Form) need to be signed and submitted on the date. This will be asked for in the documents you send us.
Can I pay by direct debit?
Warm Kop Grasweg prefers you to pay by direct debit. During the first login, you may or may not have opted for this. You can change your payment preferences in the customer portal.
What is the privacy policy of Warm Kop Grasweg?
Our privacy policy can be found on this page.
What are the terms and conditions for connection, delivery and general terms and conditions?
See the PDF documents on our page documents.
In the customer portal it says that I have not paid an invoice. This is not correct. What about this?
In principle, we update the incoming payments every Monday. We therefore ask for your patience before the payment is visible. If you receive a reminder e-mail even though you have already paid the invoice, please contact our customer service staff via telephone number 085 - 004 43 76 or
How can I (financially) sustainably use my heat installation?
  • Every 2-3 hours the system checks if it needs to heat/cool. It takes 8-10 hours before the room temperature can be adjusted to the requested temperature. If you want to go from a low temperature to a high temperature, this costs extra power. That is why we recommend that you leave the thermostat at a constant temperature;
  • Try not to leave windows and doors open unnecessarily to avoid heat/cold loss;
  • The balance ventilation on a normal/low setting reduces the flow of cold/hot outside air into your home;
  • It is important that the floor heating can properly dissipate the heat;
  • Handle tap water sparingly.

Technical questions

What should I do in case of a calamity or malfunction?
Please take a look at our page Malfunctions. In the event of an emergency (major malfunction), you can always contact us directly by phone at 085 - 004 43 76 (choose 1). If you are unsure about the severity of the fault, you can also choose Other questions and consult with our customer service.
Are there now (or soon) any works on the system?
In case of scheduled servicing or updates about malfunctions, we will post a news item on the page Malfunctions.
How can I read my heat meter / hot water meter?
The energy meter manual, like all other important documents, can be found on the documents.
How do I turn on the cooling?
Cooling starts working when you turn on the automatic control for heating/cooling. You set the AUTO programme by keeping the P button pressed until AUTO appears in the display. Cooling starts when the room temperature has reached the lower limit of 21 °C and is at least 3 °C higher than the desired temperature. When the cooling starts, you will see a snowflake on the display. After some time, the floor heating distributor should be 16-18 °C.
What should I do in case of a (prolonged) holiday/absence?
Set the thermometer to the absence function/airplane mode (airplane symbol) on your device. The absence function/airplane mode regulates the temperature of your home to the set absence temperature but does not switch off the supply of cold or heat. Please note: The absence function does switch off hot water. To stop heat supply, close the leftmost red valve at the bottom of the Driesbox. Via settings (gear icon) you can specify the number of days of absence.
How can I prevent usage of heat in the summer?
During summer, you can cool your home by setting the thermostat to a temperature lower than 21 degrees, say 15 degrees. This prevents your house from heating up when the temperature is lower than your thermostat (for example 20 degrees).
Can I turn off the cooling completely, for example in summer or winter?
Heat or cooling can be switched off and on. The procedure for cooling is explained below. Switching cooling off works as follows: You can make a one-off free request via a mail request with the subject line "Koeling uit + [street-house number]" to to turn of your cooling. You do continue to pay the fixed monthly fee for your cooling. Would you like to turn the cooling on again? You can do so by sending an e-mail request with the subject "Koeling aan + [street-home number]" to A connection fee of €42.95 will be charged for this.
Can I turn off the heating completely, for example in summer or winter?
Heat or cooling can be switched off and on. The procedure for cooling is explained below. Switching heating off works as follows: You can make a one-off free request via a mail request with the subject line "Warmte uit + [street-house number]" to to turn of your heating. You do continue to pay the fixed monthly fee for your heating. Would you like to turn the heating on again? You can do so by sending an e-mail request with the subject "Warmte aan + [street-home number]" to . A connection fee of €42.95 will be charged for this.


Further questions

Is your question not listed here? You can reach us via our contact details at the contact page.