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The steep rise in energy prices is forcing home owners to reconsider their heating source and replace or improve the existing heating system. After all, the right decision can result in significant savings, especially if a heat pump is installed. However, such an investment includes both the heat pump and the installation of the right heat emitters to ensure optimal energy efficiency. In existing homes this might not always seem very practical, but luckily there is an efficient and, most importantly, cost-effective solution; you can simply replace the existing radiators with (ultra-)low temperature radiators without much construction work.

A heat pump doesn’t automatically entail underfloor heating

Heat pumps are an increasingly popular solution to help improve a building’s energy efficiency. They use renewable energy sources for heating and cooling and, under ideal conditions, generate 3 to 5 kWh thermal energy from 1 kWh of electricity, depending on the design temperatures. This means users are able to save substantially on their energy consumption and minimise their heating costs. To optimise a heat pump’s efficiency, however, it needs to be combined with the right heat emitters. Most people still automatically link the installation of a heat pump with the expensive and time-consuming job of installing underfloor heating and new flooring. Luckily, low temperature and ultra-low temperature radiators provide a good alternative to reduce energy consumption in properly insulated buildings. 

Radiators as the efficient alternative

A heat pump works best with low system temperatures and it’s true that radiant heating solutions such as underfloor heating or panel systems are a very good match for this. However, they are certainly not the only available options. A heat pump can also be operated efficiently in combination with (ultra-)low temperature radiators. It’s possible that the existing radiators are already sufficiently dimensioned to deliver the desired heat with flow temperatures of up to 55°C. Nonetheless, when switching to low temperature heating in an existing building, the condition and lifespan as well as the performance of the old radiators should be checked and optimised to allow for the flow temperatures to be lowered. Moreover, it’s important to ensure that areas such as the windows, roof and walls are sufficiently insulated to prevent heat loss and maximise energy efficiency. 

The heat load must be recalculated for each room to determine the appropriate radiator. Depending on the degree of insulation and the newly calculated heat load, the lowest possible flow temperature can be determined. If the calculated temperature is higher than 40°C, modern panel radiators can be used. If it’s lower than 40°C, it’s best to use fan-supported panel radiators such as the Ulow E2 or fan convectors since there is increasingly less natural convection below this temperature level. 

Cost-effective heating solution for renovations

In case of an existing building, installing suitable radiators is not only a very efficient but also more cost-effective solution. Integrating a new underfloor heating system and new floors in an existing building that originally used radiators will cost at least € 40 to 80 per m2, depending on the underfloor heating system you choose and the country you live in. If you replace some of the existing radiators, on the other hand, and adjust the others, it will only cost about € 4000 to 5000 for a building with a surface area of 130 m2. On top of that, you won’t have to plan a major, time-consuming renovation. 

Studies have shown that in energy-efficient buildings, i.e. with adequate insulation, the annual cost of heating with radiators is slightly lower than with underfloor heating. They are about 15 % more energy-efficient in single-family homes and up to 10 % in apartment buildings. Furthermore, replacing old radiators with (ultra-)low temperature radiators significantly reduces the initial cost of modernising the heating system and renovating the building. Therefore, there is no reason for home owners not to install a heat pump if they are currently using radiators. The solution is simply to replace most of the radiators. All it takes is a good installer and a few hours of work, depending on the number of radiators to be replaced.

Which radiators to match with a heat pump?

Heat pumps work just as well with matching radiators as with underfloor heating. Moreover, thanks to the attractive design of our panel radiators, they can easily act as an additional design element in any interior. Here are a few radiators that are a perfect match for a heat pump in a modernised and properly insulated building: 

• The Compact, for example, is the most economical solution. In a traditional heating system with cast-iron fin radiators, the Purmo Compact with a height of 550 mm offers a one-on-one replacement solution as it has the same centre-to-centre distance as the old cast-iron radiators. 
• Plan Compact & Ramo Compact are also a very good match for a heat pump. Plan Compact has a completely flat front panel that creates a sleek look for an easy integration in any décor. Ramo Compact has a modern design with a decorative flat front panel that is embossed with fine lines. 
• Vertical designer radiators such as Faro V and Kos V are a good alternative as well. They not only create a sense of height, but also provide a powerful heat source in interiors where there’s not much available wall space. 

Radiators such as Flex, Tinos H Flex and Tinos V are available with a bottom connection for a more discreet installation. This is a perfect solution if you also plan to modify the water supply system and hide the pipes in the wall. 

For flow temperatures of 40°C or less, other heat emitters are more suitable. 

• The Ulow E2, for example, is an ultra-low temperature radiator which is powered by innovative E2 technology that automatically switches on the integrated fans when needed to support the natural convection of the radiator. The increased performance of the Ulow E2 allows for both lower temperature settings and a reduced energy consumption. 
• The iVector S2 offers high outputs in low temperature heating, but when paired with a reversible heat pump, also has full cooling functionalities. Thanks to its built-in controller that regulates the system’s parameters optimal indoor comfort is guaranteed all year round. The sleek Italian design and the various installation options, ranging from wall-mounted or in-wall to on or even in the ceiling, allow for a smooth integration in any interior. 

Underfloor heating systems for renovations

In case there is a strong preference for underfloor heating when setting up a low temperature system in an existing building, our ts14R underfloor heating system offers a great solution. This system for dry construction is suitable for almost all renovation projects. It has a low weight and a total construction height of only 30 to 40 mm, including the floor covering laid directly on the system boards and the insulation layer. Thanks to its aluminium heat-conduction plates already factory-mounted on the insulation, the ts14R system offers a fast and even heat distribution on the floor.

More information about our energy-efficient heating solutions is available on our website. If you have any questions or want to know more about our products and services, don’t hesitate to get in touch.