[batushka5]

These units are ubiquitus in northernish Europe, as any new/renovated building needs them to reach A/A++ energy effiency. Brands like Komfovent, SystemAir, offering 200 m³/h ducted units for 2000 Euros, with efficiency like:

  Outdoors    °C -23  -15  -10  -5    0   25   30   35
  After unit, °C 12,9 14,5 15,5 16,5 17,5 22,6 23,6 24,6

with indoor conditions + 22 °C, 20 % RH