Push-Pull Decentralised HRV/ERV Products

Smaller decentralised “push-pull” units, such as the LUNOS e²60 or Stiebel Eltron VLR 70, work on a reversing cycle rather than continuous two-way flow. Each unit has a single fan and a ceramic/plastic/metal thermal accumulator. During the exhaust phase, warm stale indoor air is blown out through the core, charging it with heat (and some moisture in the case of ERV-type ceramics). After a set period — typically around 70 seconds — the fan reverses direction, drawing in fresh outdoor air. As the air passes back through the warmed core, much of the stored heat is transferred to the incoming supply air. By pairing two units to run in opposite phases, a balanced supply and extract airflow can be achieved across a dwelling, providing effective heat recovery and fresh air without the need for ductwork.