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One day turnaround: replacing gas boiler with heat pump in German home

Daikin Altherma 3 H HT heat pump installed in 150-year-old home in Germany, capable of working in -15 °C outside temperatures.


The Weinmann family live in a large 150-year-old farmhouse in Germany. The property underwent a substantial renovation in 1979, and a gas condensing boiler was then installed in 1999.

Homeowners Volker Weinmann and his wife were interested in replacing their gas boiler with a climate-friendly heating system before winter closed in. In Germany, as in Ireland, there are state subsidies available for people looking to modernize their heating by installing a heat pump. As these super energy-efficient systems can reliably heat old buildings with high flow temperatures, the couple opted for a heat pump.

The main challenge the Weinmann couple faced was that their heating wasn’t housed in the basement, as is usually the case, but in the attic of their home.


Volker knew about Daikin heat pumps and had one in mind that was a perfect fit for their house, one that would also work with their home’s existing radiators. With his local installer, he selected a Daikin Altherma 3 H HT air-to-water heat pump and, with the installation taking just one day to complete, his 22-year-old gas condensing boiler was history and the heat pump was ready for operation.

The Daikin Altherma 3 H HT air-to-water heat pump was developed specifically for older homes, with flow temperatures of up to 70 °C at minus 15 °C outside temperature. This model meant the Weinmanns could keep their radiators as the main heat emitters in the house.

The Daikin Altherma 3 H HT indoor unit has a small footprint (59.5 x 62.5 cm) and a height of just 1.65 m of the indoor unit – an important factor due to where the heat pump would be installed in the home.  Another advantage of the Altherma 3 H HT is the particularly quiet outdoor unit, which the couple installed under the kitchen window outside, with only 35 dB (A) (at a distance of three metres). This is roughly equivalent to the noise level of whispering in a library!



"Now was the right time for us to convert to renewable energies. Heat pumps can save fossil fuels, almost all of which have to be imported, and replace them with domestic energy – green electricity and environmental heat. Together with electricity generated from renewable sources, the heat pump can replace oil and gas in carbon-neutral manner. 

“Our staircase is only 85 cm wide at the narrowest point, this is why we chose the Daikin system due to its  compact indoor unit, which even fit through our narrow staircase!”

              – Volker Weinmann, Homeowner

Daikin Altherma 3

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Products used on this project

Daikin Altherma high temperature split

Daikin Altherma 3 H HT - EPRA014-018DW

Daikin Altherma low temperature split

Daikin Altherma 3 H HT - ETVH

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