How to read a German district‑heating (Fernwärme) contract before you buy

The legal framework you must read first

District‑heating supply in Germany is governed by the Federal regulation “Verordnung über Allgemeine Bedingungen für die Versorgung mit Fernwärme” (AVBFernwärmeV). The AVBFernwärmeV sets out mandatory minimum rules for supplier–customer relations (notice, information duties, what the supplier may require in contract terms) and is the primary legal text to consult when you see a Fernwärme contract. See the consolidated AVBFernwärmeV text on the official laws portal for the exact wording. ([gesetze-im-internet.de](https://www.gesetze-im-internet.de/avbfernw_rmev/BJNR007420980.html?utm_source=openai))

The federal ministry has been actively revising these rules; in the government’s August 26, 2026 press material the ministry described a Wärmenetzpaket to modernise the AVBFernwärmeV and related rules and to improve transparency. Drafts and change proposals from the ministry explain that some formal requirements (for example the required form of supplier notifications) are being modernised and that contracts remain subject to general AGB (standard‑term) law and transparency review. If a contract refers to future law changes, note the dates and ask the supplier for the current operative version. ([bundeswirtschaftsministerium.de](https://www.bundeswirtschaftsministerium.de/Redaktion/DE/Pressemitteilungen/2026/08/20260826-eckpunkte-waermenetzpaket.html?utm_source=openai))

What to look for in indexation (price‑adjustment) clauses

Many Fernwärme contracts allow the supplier to change prices during the contract term. The AVBFernwärmeV requires that customers be informed and gives rules about how and when a customer can react to a price change — including a short termination window after a supplier‑initiated change. When you read the clause, look for: (1) the trigger (which index, which input costs), (2) the exact formula (is it a percentage change of a named index, a weighted basket, or a fixed surcharge?), (3) base period and reference index publication (for example a named CPI series with base month and official publisher), and (4) caps, floors or automatic limits. If the clause is vague („Anpassung an die Kostenentwicklung“ without a named index), that is a transparency risk under AGB law. ([gesetze-im-internet.de](https://www.gesetze-im-internet.de/avbfernw_rmev/BJNR007420980.html?utm_source=openai))

Also check the notice procedure: the AVBFernwärmeV and ministry drafts require suppliers to notify customers when they exercise a contractual price‑adjustment right; in some cases the regulation gives customers the right to seek an immediate review and possible reduction. Importantly, the regulation’s rules create short statutory deadlines for a customer to react (read the notice carefully and calendar the deadlines). ([gesetze-im-internet.de](https://www.gesetze-im-internet.de/avbfernw_rmev/BJNR007420980.html?utm_source=openai))

Transfer and assignment: what happens at sale

A sale of the building does not automatically cancel a supplier’s contractual rights. Check whether the contract is tied to the meter/connection or to the property owner, and whether it contains an automatic assignment clause or requires the supplier’s consent to transfer. Many supplier terms prohibit onward supply to third parties without written consent; that rule is explicitly reflected in the AVBFernwärmeV for the use of heat. If the buyer will be the new contractual customer, require a written confirmation from the supplier that the contract can be assigned or that a new supply contract for the same connection will be issued at takeover. ([gesetze-im-internet.de](https://www.gesetze-im-internet.de/avbfernw_rmev/__22.html))

Also obtain from the seller and supplier a statement of outstanding balances, any security deposit held, meter readings at handover and whether reconnection or administrative fees apply. If the existing contract contains a minimum term or early‑termination fee, get the precise expiry date and formula in writing; those charges are often enforced by the supplier even after a change of owner unless the contract expressly allows assignment. When in doubt, require the notary to condition completion on supplier confirmation (ask your German lawyer or Notar to draft that).

Six specific questions to send to SWM, Mainova or Vattenfall

Send these as numbered, short questions by e‑mail and attach the draft sales contract or the property address and connection number.

1) Please provide the full, current General Terms and Conditions and the specific supply contract for this address (PDF), and confirm whether an English version or certified translation is available.

2) Which exact price‑adjustment formula applies to this connection? Name the reference index (publisher and series), the base/reference period, and show the calculation for the last three changes (date, percentage, new tariff).

3) Are there caps, floors, minimum‑consumption clauses, minimum term commitments or early‑termination fees? If yes, give the legal clause, calculation examples and expiry dates.

4) On what legal basis would the contract be transferred on sale? Does assignment require supplier consent? Please confirm the procedure, the documents required and the expected processing time.

5) Please provide the latest meter reading, any outstanding balance, any security deposit held, and a list of administrative fees (reconnection, relocation, contract change) with exact amounts.

6) If we request a contract takeover on completion, will the same tariff and conditions continue, or will a new contract be issued? If a new contract may be required, provide the draft terms and the earliest effective date.

Keep replies as evidence for the notary; if a supplier’s answer is vague, insist on a signed clarification.

Practical next steps and risks

Do not rely on verbal assurances. Before signing a purchase contract: obtain the supplier’s written answers to the six questions above; secure a copy of the operative supply terms; and ask your Notar to make the purchase conditional on written supplier confirmation of assignment or a new contract. If price‑adjustment language is vague, treat it as a negotiation point or require a cap. For contract‑specific legal advice (drafting notarial conditions, interpreting a foreign‑language clause), instruct a German lawyer experienced in energy or real‑estate law. The AVBFernwärmeV remains the baseline regulation to challenge unclear clauses. ([gesetze-im-internet.de](https://www.gesetze-im-internet.de/avbfernw_rmev/BJNR007420980.html?utm_source=openai))

For large purchases or portfolios, add a contract‑by‑contract spreadsheet with: contract start, term, index formula (exact text), cap/floor, outstanding deposits, last price change date and supplier confirmation to transfer. That list is the single most useful due‑diligence deliverable when you negotiate price allocation at completion.