Energy efficiency starts with ventilation

A rotary heat exchanger can significantly reduce energy consumption

Did you know that a domestic Enervent Zehnder ventilation unit, could save up to €2,000 per year on heating costs? An energy renovation of your property can pay for itself in as little as three years. By installing a rotary heat recovery system, you can achieve energy efficiency levels of over 85%. Read more and take the step towards more sustainable energy use.

Focus on ventilation

In a typical household, over 10,000 kWh of energy is lost annually if heat is not recovered from the exhaust air.

The following ventilation solutions are generally used in single-family homes:

• Natural ventilation
• Roof fan ventilation
• Ventilation units with crossflow, counterflow, or exhaust air heat pumps

This comparison focuses on energy savings of different ventilation methods, from basic to advanced systems.

With natural ventilation or roof fan ventilation, exhaust air is expelled without any energy recovery – resulting in 100% heat loss.

An older ventilation unit with a crossflow heat exchanger can recover approximately 50% of the energy in the exhaust air. A newer unit with a counterflow heat exchanger has an efficiency of around 70%, while the most advanced technology, rotary heat recovery, reaches an average efficiency of approximately 85%.

For example, in a medium-sized household with an airflow of 70 l/s (supply and exhaust) and a duct pressure loss of 60 Pa, and assuming an electricity price of € 0.29/kWh, replacing a 20-year-old ventilation unit (with a crossflow heat exchanger) with a new unit featuring rotary heat recovery, could result in annual savings of approximately € 1,800.

This means that the payback period for a new unit would be 3–4 years.

Assuming electricity prices remain stable, the total savings over the unit’s typical 25-year lifespan could amount to approximately € 45,000.