Heat pump with radiator: Does that make sense?
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Stefano Fonseca is an energy and environment engineer with over six years of experience in technical building equipment (TGA). He combines technical expertise with a passion for understandable communication. For more than five years, he has been writing as a freelance editor about renewable energy and sustainable living, in particular about photovoltaics and heat pumps.
If you combine a heat pump with classic radiators, the question is: Does that really make sense? In old buildings and existing heating systems in particular, it is important how well the components harmonize with each other. In this article, you will find out which requirements must be met so that the connection between heat pump and radiator works efficiently — and when it makes more sense to use other solutions.
Heat pump with radiator: Is that even possible?
A heat pump can be operated with radiators if certain requirements are met. The radiators must be designed for low flow temperatures (below 55 °C). Heat pumps usually operate at lower temperatures than conventional heating systems. Good insulation of the building is important for this. In old buildings, additional adjustments are often necessary for efficient use.
When is a heat pump not useful for radiators?
A heat pump is less suitable if the building is poorly insulated or the existing radiators are not sufficiently dimensioned. In such cases, the heat pump would require more energy to deliver the desired heat. This in turn reduces their efficiency. Even with older heating systems such as single-pipe heaters Operating a heat pump can be expensive and impractical.
Which radiators are suitable for heat pumps?
Low-temperature radiators and panel heaters are particularly suitable for heat pumps, as they work more efficiently with the low flow temperatures of the heat pump. These radiators can provide the required heat even at lower water temperatures, which supports the efficiency of the heat pump. Radiators are only conditionally suitable, unless they are large enough and the building is well insulated.
Can a heat pump also work with old radiators?
A heat pump can also work with old radiators, but only under certain conditions. This is because old radiators are often not designed for the low flow temperatures of a heat pump, which can impair efficiency. You must therefore ensure that the existing radiators are suitable for operating a heat pump.
You can find out whether you can use existing radiators with a aptitude test out:
- Attitude: On a cold day, set the boiler flow temperature to 50 to 55 degrees Celsius.
- Thermostats: The thermostats on the radiators are set to 20 degrees Celsius.
- Check heating: After a few hours, check that the house is heated enough.
- Outcome: If the flow temperature of 55 degrees is not sufficient for you to heat your single-family home adequately, then further measures may need to be taken, such as replacing the radiator.
In many cases, replacing old radiators with low-temperature radiators significantly improves the performance of the heat pump.
What are the costs of replacing radiators in existing buildings?
The costs for replacing an individual radiator in existing buildings are usually between 200 and 500 euros, depending on the size and type of radiator. For a single-family home (EFH), the total cost of replacing all radiators can be around 2,000 to 6,000 euros. This includes both material costs and labor costs for the removal and installation of the new radiators. Depending on the complexity of the replacement and the necessary adjustments to the heating installation, prices may vary.
Experiences: Heat pump and radiator in everyday life
Homeowners' experiences with combining heat pumps and radiators vary depending on the type of building, insulation and the radiators used. In many cases, users report efficient use, but also challenges in adapting existing heating systems.
In this Experience report There is a discussion about the usefulness of combining heat pump and radiators. Users stress that it is crucial whether the radiators are large enough and whether the heat pump is designed for lower flow temperatures. Replacing the radiators is recommended.
In this forum post Users comment on the practicality of heat pumps with radiators. Particular emphasis is placed on the need for good insulation and the selection of the right radiators so that they work optimally with the heat pump. Negative experiences arise in particular when the radiators are not suitable for low flow temperatures.
In this forum post Users report on their experiences with connecting an air-water heat pump and radiators. In older buildings in particular, the change was described as challenging, as the radiators are not sufficient for the low temperatures of the heat pump. Replacing or adjusting the radiators was necessary for many.
Which heat pump is best for radiators?
air source heat pumps and geothermal heat pumps are suitable for radiators, especially if they are equipped with modern refrigerants such as R290 (propane). They provide high flow temperatures and can therefore continue to operate the existing heating system without major adjustments. In the old building, high temperature heat pumps be an alternative. They reach water temperatures of up to 75°C and are therefore ideal for use with classic radiators.
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