Power supply cut-off periods for heat pumps: What does this mean and what needs to be considered?
%25203%2520(1).webp)
Stefano Fonseca is an energy and environment engineer with over six years of experience in technical building equipment (TGA). He combines technical expertise with a passion for understandable communication. For more than five years, he has been writing as a freelance editor about renewable energy and sustainable living, in particular about photovoltaics and heat pumps.
The heat pump suddenly stops — in the middle of winter, for no apparent reason. This is often caused by the so-called EVU lock. In this article, you can find out what these blackout periods are all about, when they occur and how to protect yourself from loss of comfort.
What is an EVU lock on heat pumps?
An EVU lock is a temporary shutdown of the heat pump by the network operator. It concerns controllable consumer devices such as heat pumps and is used to stabilize the grid. The heat pump must not run during the cut-off period, but will then restart automatically.
Why are there cut-off periods for heat pumps?
Blackout periods for heat pumps reduce the load on the power grid during peak load periods. Network operators switch off the devices for a short time and thus ensure network stability. This measure supports load management as part of the energy transition. Consumers benefit from lower network charges.
How long do blackouts last and when do they occur?
Lockdown periods for heat pumps last a maximum of two hours in a row and may take place up to three times a day. They usually occur in the morning or evening when the power grid is heavily loaded. Precise control is provided by the network operator.
How do you recognize an active lock?
An active EVU lock can be recognized by the fact that the heat pump suddenly shuts off and no heating or hot water operation is possible. Many devices show the lock on the display or in the app. Older systems are often shut down silently, controlled by a round control receiver or digital meter.
What effects do EVU cut-off periods have on the heat pump?
During the EVU cut-off period, the heat pump is switched off and cannot generate heating or hot water. This is hardly noticeable in well-insulated buildings. In contrast, poorly insulated houses can result in temperature losses and loss of comfort. At the end of the cut-off period, the heat pump automatically restarts.
What can you do about loss of comfort?
Losses of comfort during EVU blackouts can largely be avoided with the following measures:
What does the law say? (Section 14a EnWG)
Since January 1, 2024, Germany has had the revised provision of Section 14a of the Energy Industry Act (EnWG), which relates to so-called taxable consumer devices. These include heat pumps, wallboxes, energy storage and air conditioning systems with an electrical connection of more than 4.2 kW, which were put into operation from that date.
Operators of new controllable consumer devices must register them with the responsible network operator. The systems must be equipped with suitable control technology that enables network-oriented control.
In return for providing their systems for network-oriented control, end customers receive reduced network charges. There are various models available, including flat rate or percentage reductions.
Does every heat pump have to have an EVU lock?
Not every heat pump is subject to an EVU lock. Whether a heat pump is affected by such a lock depends on several factors:
When is a heat pump with an EVU lock worthwhile?
A heat pump with an EVU lock is particularly worthwhile if the building is well insulated or has a buffer or hot water tank. Anyone who also wants to benefit from discounted network charges can reduce electricity costs in the long term by participating in load management. Professional planning, which takes into account the heat requirement, the size of the storage tank and the control technology, is crucial.
autarc: Your partner for efficient planning of heat pumps — find out more now!
Rely on quality and expertise when planning and installing heat pump systems. With our Heat pump check receive comprehensive support so that you can implement your projects efficiently and sustainably. Contact us today and benefit from our expert knowledge!