Retrofitting underfloor heating in an existing property can enhance energy efficiency and comfort, but it comes with costs that vary widely. For those planning a renovation, understanding these expenses is key. Plumbed-in or wet systems, which circulate warm water through tubing beneath floors, are the most common retrofit solutions. These systems typically operate at lower temperatures than radiators, making them cheaper to run. Underfloor heating only requires water heated to approximately 35°C, while the flow temperature in radiators is around 60°C – typically making this solution cheaper to run.
What Drives the Cost of Retrofitting Underfloor Heating?
The cost of retrofitting underfloor heating depends on several factors, including the size of the system, the location within the house, and the condition of the property. For a standard project, budgets range from £36 to £120 per square meter, excluding VAT. Additional installation costs can vary from £224 to £720, with London installations reaching up to £1,000, according to Tom Edmunds of Wunda Group PLC. The size of the system directly influences costs, with larger setups generally offering economies of scale, though they may require additional technical expertise, such as screeders or electricians.
Opting for a DIY system can reduce costs, but the amount of materials and piping required will depend on the product and its location. Tom Edmunds advises discussing money-saving options with suppliers. “Ensure your chosen underfloor heating system includes clear installation guides and technical support from the supplier to simplify work for follow-on trades and reduce their time on site,” he adds.
Room-Specific Challenges and Energy Efficiency
Installing underfloor heating in bathrooms and kitchens can be more complex due to the need for precise pipe routing and limited usable space. Jo Snell of Nu-Heat emphasizes the importance of early planning with an experienced supplier to ensure a smooth setup. Centralizing the manifold under stairs or in hallways can also reduce costs by minimizing additional pipes.
The energy efficiency of the existing property plays a significant role in system performance. Poor insulation can lead to heat loss, increasing running costs. Upgrading insulation and addressing structural issues like draughts or dampness in older homes can add to initial costs but reduce long-term expenses. Tom Edmunds notes that windows and external doors are major sources of heat loss, accounting for 10-20% of heat loss. “Installing high-performance doors and glazing is one of the best long-term solutions to improve energy efficiency and cut bills,” he says. Specifying quality blinds or thermal lined curtains is a cost-effective solution that can be applied immediately to ensure the UFH system performs optimally.
In a case study of an East London cottage renovation, electric underfloor heating was installed in the bathroom, providing even warmth and reducing the risk of slipping. The project also included sustainable materials like jute insulation, showcasing how underfloor heating can be part of a broader energy-efficient upgrade. The cottage’s rare 32-metre-long garden and attractive period features attracted the owner, who sought to create a sustainable and healthy home.
Floor build-up and the need for new flooring materials can also impact costs. Low-profile overlay systems are often easier to install but may be more expensive. The type of flooring, such as tiles or hardwood, can affect labor intensity and project duration. Ensuring a flat, clean floor surface is essential for a smooth installation, and retaining original features like floorboards in period properties can add time and cost. While this could increase upfront costs, ensuring proper insulation is vital for the ongoing efficiency of the UFH system.
Installation considerations
A typical retrofit assumes a flat subfloor, such as concrete or screed, and a single rectangular room without major repairs required before work begins. Choosing a DIY-oriented kit can lower material costs, especially when homeowners are comfortable laying laminate flooring and handling basic pipe layout themselves.
Integrating UFH with home renovations
Selecting the floor finish influences labor intensity; tiles and stone demand more preparation than carpet or laminate, while hardwood may need sub-floor modifications to accommodate heating elements. Low-profile overlay systems can be installed over existing flooring, with a typical thickness of around 15 mm, limiting floor-height increase and often avoiding the need for extensive screed work.
