Anyone who heats an old building will be familiar with the situation: the radiators are old, the flow temperatures are high, and now it’s time to switch to a more efficient system. More and more often, the question arises as to whether the existing radiators are even suitable for lower system temperatures. The answer is not a general one, but depends on several factors that you should know before you plan or invest. <\/p>\n
A low temperature is a heating mode in which the flow temperature is permanently below 55 degrees Celsius, usually between 35 and 45 degrees. Modern heat pumps are designed to operate as close as possible to these temperatures because their efficiency increases as the flow temperature falls. Conventional gas heating systems in old buildings, on the other hand, often work with flow temperatures of between 70 and 90 degrees. <\/p>\n
This means that a radiator designed for 75\/65\/20 degrees delivers significantly less heating output at a flow temperature of 45 degrees. How much less depends on its size, design and the insulation standard of the room. <\/p>\n
Three factors determine whether low-temperature operation works in an old building: the building envelope, the available heating surface and the desired room temperatures.<\/p>\n
A poorly insulated building with high transmission heat loss requires significantly more energy per hour in the heating load calculation than a renovated house. If you rely on low flow temperatures with poor insulation, there is a risk that the radiators will no longer be able to compensate for the heat losses in winter. In this case, only a combination of insulation measures and a larger heating surface will help. <\/p>\n
Hydraulic balancing is not an option, but a must. It ensures that all radiators in the house have an even flow and that the flow temperature can be lowered as much as possible without individual rooms remaining cold. <\/p>\n
Get more information now.<\/a><\/p><\/blockquote>\n
The bathroom as a special case<\/h2>\n
Different requirements apply in the bathroom than in the living area. While 20 to 21 degrees is considered comfortable in the living room, 24 degrees and more is often desired in the bathroom. At the same time, the bathroom in many existing buildings is small and the existing radiator is rarely large enough to reliably reach this temperature with a low flow rate. <\/p>\n
What’s more, a bathroom radiator not only has to heat the room, but also dry towels and provide thermal comfort after showering. This short-term high heat requirement can often not be met with purely low-temperature operation via the central heating system. <\/p>\n
When additional heat in the bathroom makes sense<\/h2>\n
This is precisely where the concept of electric auxiliary heating comes in. An electric bathroom radiator such as the Evelino EB<\/a> from Caldo works independently of the central heating system and provides heat quickly when required without the entire heating system having to be started up. It is particularly suitable as a supplementary heat source for low-temperature heating systems that cannot be raised to higher temperatures at short notice. <\/p>\n
This is not a contradiction to energy-efficient operation, but a practical solution for a room with special requirements. The Evelino EB complies with the Ecodesign Directive ErP and Regulation (EU) 2015\/1188, is equipped with a digital heating cartridge and has a booster function, weekly program, frost protection and window detection. <\/p>\n
Realistically evaluating domestic radiators in existing buildings<\/h2>\n
In the living room, an existing radiator can often provide sufficient heat even at a slightly lower flow temperature if the room is well insulated and the radiator is large enough. In many old buildings, the radiators were oversized anyway, which is an advantage today. <\/p>\n
If you want to make a targeted exchange, Caldo offers domestic radiators such as the Liscio<\/a> or the Adriano<\/a>, which work efficiently even at moderate flow temperatures thanks to their flat design and large heating surface. Technical data and performance specifications can be found in the data sheets in the download area<\/a>. <\/p>\n
Conclusion: Low-temperature radiators in old buildings need an honest assessment<\/h2>\n
Whether low-temperature operation works in old buildings cannot be answered with a blanket yes or no. The decisive factors are the insulation standard, heating surface size and system balancing. In this context, the bathroom is often the most critical room because it combines the highest comfort requirements with the smallest available area. A well-chosen additional electrical solution closes this gap reliably and economically. <\/p>\n