What Costs Can Be Expected When Retrofitting Underfloor Heating?

1 Labour Costs

Even though labour costs for installing a heating system are not usually listed separately when commissioning a specialist company, it is reasonable to assume that they account for a significant proportion of the project cost. This is particularly true of some renovation projects, where the costs of removing and disposing of old flooring and installing additional thermal insulation must also be considered. These preparatory measures can cost an additional €20-30/m². If a heating load calculation is required, these costs must also be taken into account. For a single-family home, the approximate cost is €300 to €1,000, depending on the living space and number of rooms. 
As a general rule, the larger the project, the lower the cost per square metre.

On top of this, it can be difficult to find a heating engineer in some regions who can carry out the installation within a reasonable timeframe using the desired technology. Therefore, installing the system yourself significantly reduces the cost of retrofitting underfloor heating and increases flexibility when carrying out the installation. FLEXIRO thin-layer systems were specifically designed for this application to enable cost-effective retrofitting. Every step you complete yourself, including the preparatory work and laying the floor covering, will help reduce costs.

2 Cost of materials for floor construction

The cost of constructing the floor is largely determined by the existing subfloor and the installation method used. If the existing floor is already stable and level, no additional structural measures are required.

With the classic wet method using a thermal screed layer and thick hoses, significantly higher material consumption, high weight application and long drying times must be expected. Thin-layer systems, on the other hand, require as little as 25 kg of filler per m² depending on the installation method. When installing in drywall construction, the surface covering can be applied after just 1-2 days of drying time.

3 Costs of components for heating technology

The cost of heating technology components, such as system panels, pipes and underfloor heating control technology, depends on the installation system used. While simple installation methods such as tacker systems or clip rails are less expensive, they are more labour-intensive. Installation in studded or milled drywall panels is faster and saves on floor levelling compound. In terms of installation time, the drywall option is unbeatable: Rooms that have been thermally modernised using a dry system can be used again after just two to three days, whereas rooms using a wet system sometimes have to be left to dry for weeks before work on the floor covering can be completed.

Control technology is an important cost factor. It can account for a significant proportion of costs, particularly when installing underfloor heating in small spaces. If a connection to a heating circuit distributor is available, this item can be omitted. In this case the costs of the distributor should be allocated to the retrofitted areas. In all other cases, the heating surface is connected to the existing heating system using RTL technology. The cost per square metre is largely determined by the size of the controlled heating surface. At FLEXIRO, we have chosen high-quality RTL valves with a flow shut-off to ensure that any subsequent maintenance can be carried out without difficulty. Overall, it is important to ensure that the technology, pipes and connections used are of a high standard. Once the floor is finished and sealed, leaks are difficult to repair.

Therefore, pressure testing and trial runs are particularly important. The additional costs of renting or purchasing a pressure test pump must be taken into account.

Although many project-specific factors influence the total cost of installing underfloor heating, the table below offers guidelines for cost estimation.

The cost of the heating technology itself often accounts for less than 50% of the total cost. Depending on the installation method and size of the heating surface, this proportion can even be significantly lower. This is particularly true if a specialist company is commissioned to carry out the work. However, since the heating system is expected to function for decades, it is important to ensure that the components are high quality.

The larger the heating surface, the lower the price per square metre. It may therefore be worth considering installing underfloor heating in several rooms at the same time. The thin-layer variant is slightly cheaper than classic underfloor heating with heated screed, and it puts less weight on the subfloor. In addition, lower operating costs can be expected due to the low flow temperatures. However, dry construction systems are significantly more expensive to purchase. However, the substantial reduction in drying times means that some of the costs are offset. Installing the system yourself offers the greatest potential for savings when modernising your heating system and allows for additional flexibility in implementation.

Although the list shows cost advantages for thin-layer systems, the decision on the right underfloor heating system should be based more on requirements than costs. Can the installation be carried out by the homeowner? How much installation height is available? Is the subfloor load-bearing and impact-resistant? Is the floor intended to store heat or is dynamic heating behaviour desired? The choice of system depends on the answers to these questions. However, when retrofitting underfloor heating, thin-layer variants usually offer more advantages than disadvantages.