Incorrect invoice: The customer can refuse payment.

A client of an installer wanted to deduct his new heating system from his taxes. Because the installer's invoice contained errors, he refused to pay the labor costs. The Higher Regional Court of Hamm ruled that he was justified in doing so.

This article is part of the special topic Tax bonus for tradesmen's invoices: What you should know

If the craftsman places a incorrect invoice, the client has a Right of retention on the contract price – at least if he has a claim to Accounting has. This was his Tax declaration, where he wanted to deduct the cost of the craftsman's services. This right of retention means that the customer is prevented from making payment. not in default However, he must not delay in asserting his claim, the Higher Regional Court of Hamm clarified.

The case

A SHK installer had a new heating system installed on account The invoice was for approximately €11.000. It included an item he had not performed: The contract stipulated a hydraulic balancing the new system is intended to actually never took place .  

The customer explained that he had paid the invoice for his Tax declaration I need to Craftsman bonus to receive the invoice. He therefore refused to pay the incorrect bill. The tradesman then took the matter to court. The Arnsberg Regional Court ruled that the customer was entitled to payment after § 273 para. 1 BGB a Right of retention I have a problem with the payment because I never received a proper invoice.

The judgment

Following an appeal by the tradesman, the Higher Regional Court (OLG) Hamm has now slightly corrected the decision: The customer had indeed had a Right of retention, but not from the beginning.

Initially, the client should only have considered the amount that the hydraulic balancing would have cost. After § 641 para. 3 BGB He was allowed to withhold twice the required costs, totaling approximately 1.000 euros. However, he was not liable for the remaining portion of the bill – approximately 10.100 euros. actually in default advised. However, the customer only had the right to retain the goods for several months. later known as exercised which is why he was obligated to pay up to that moment.

The Higher Regional Court also clarified that in the specific individual case, the customer has a Right to accounting must have had here. tax The reason, namely the Craftsman bonus.

Since the delay did not relate to the entire contract price, the customer now had to pay an additional 506 euros on top of the correct contract price. late payment interest numbers.

Higher Regional Court of Hamm, Judgment of March 13, 2026, Ref. 12 U 138/25

When will the tradesman bonus be available?

The tax reduction to § 35a Income Tax Act is granted if it is a craftsmanship It concerns a proper on account is present and the Cashless payment Payment has been made. Cash payments should never be made, as the tax office will otherwise reject the tax benefit. 

Each year 20 percent from maximum 6.000 Euro labor costs for tradespeople (not material costs) can be deducted, resulting in savings of up to EUR 1.200 This can mean taxes. Always make sure the invoice includes the Separated wage costs identifies!

A married couple filing jointly can only claim the bonus once. The bonus applies to Work such as repairs, renovations or modernizations in the household – be it in the apartment, in the a holiday home used by the owner or in the garden. The installation of a tax-free [system/device] is also possible. Photovoltaic system This includes, unless otherwise stated. public funding was used (see BMF letter dated 17 July 2023, Ref. IV C 6 - S 2121/23/10001:001).

The advisors at the Chambers of Crafts will be happy to help you with any legal questions!

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