Flexit Nordic S3 heat recovery ventilation unit

Nordic S3 description

Flexit Nordic S3 is a heat-recovery ventilation unit (HRV) that continuously supplies fresh air throughout the building while recovering heat from the exhaust air. Flexit is a Norwegian manufacturer known for its high heat recovery (up to 84%). The Nordic S3 model is designed specifically for larger private houses and families, where both energy savings and quiet operation matter.

How Flexit Nordic S3 works

The unit draws fresh air from outside while simultaneously extracting stale air from the rooms. A counterflow plate heat exchanger transfers heat from the exhaust air to the incoming fresh air without the two streams mixing. The result is fresh, filtered supply air that in winter arrives at almost room temperature. This significantly reduces heating costs — often 30–50% compared to natural ventilation.

Energy efficiency and indoor climate

Flexit Nordic S3 suits objects of up to 200 m² and is designed to deliver the highest possible heat recovery. Supply air is filtered — typically with an F7 or better filter — which stops pollen, dust and fine particles (PM2.5). It is especially valued by allergy sufferers and families with young children. Filtered air keeps indoor CO₂ levels low, reduces moisture in bathrooms and kitchens, and prevents mould.

Control and automation

This means the unit runs only as much as needed — saving electricity and extending filter life.

Why choose Flexit Nordic S3

Flexit is well known on the Estonian market for quality, durability and long-term spare-parts availability. Nordic S3 is a popular choice thanks to its strong price-to-performance ratio and easy maintenance. We sell the unit together with professional installation across Estonia, including design, ductwork, commissioning, balancing and ongoing service and filter changes.

Nordic S3 technical specifications

Who is Flexit Nordic S3 for?

Well suited for properties with up to 200 m² of living space.

• Private house 150–200 m²
• Two-storey house
• Energy-efficient new build
• Allergy-friendly home (F9 filters)

Frequently asked questions