Fresh Air Without the Heat: How a TRUE Summer Bypass Works

A well insulated, energy efficient home relies on MVHR (Mechanical Ventilation with Heat Recovery) to provide fresh, filtered air throughout the year. In winter, the system retains warmth to keep energy use low and comfort levels high. But in the warmer months, especially during heatwaves, heat recovery is no longer beneficial – and that’s where a TRUE Summer Bypass becomes essential.

What Is a Summer Bypass?

A Summer Bypass in an MVHR system allows fresh air to enter the home without passing through the heat exchanger. This prevents the system from retaining heat during warmer periods, helping to keep indoor temperatures lower – particularly important at night when cooling is most needed.

However, not all Summer Bypass systems work in the same way or offer the same level of performance.

What Should a Proper Summer Bypass Do?

To be effective, a Summer Bypass system should:

• Maintain proper airflow – ventilation performance should remain strong

• Physically bypass the heat exchanger – allowing cooler outdoor air to enter without warming it

• Respond to both internal and external conditions – not just the outside air temperature

• Operate automatically and intelligently – adjusting based on real-time temperature and humidity levels

These features ensure comfort without sacrificing indoor air quality or ventilation efficiency.

Not All Systems Are Created Equal

Many older or basic MVHR systems rely on simplistic controls – such as slowing the fan speed or switching based only on external temperature. These methods can be ineffective, especially when indoor conditions remain warm and uncomfortable.

Modern systems with a TRUE Summer Bypass use advanced controls to assess both indoor and outdoor environments. They automatically adapt to ensure cooler, fresher air is supplied when it’s most needed, without manually adjusting settings or compromising performance.

Why It Matters

With warmer, more frequent summer heatwaves, energy-efficient homes can sometimes retain unwanted warmth. A properly functioning Summer Bypass is crucial to maintaining comfort  especially overnight, while continuing to deliver fresh, filtered air.

Future-Proof Your Comfort

An MVHR system with a TRUE Summer Bypass offers:

• Improved comfort in summer

• Consistent ventilation performance

• Intelligent response to changing conditions

Investing in the right system means better control, better comfort, and better indoor air – all year round.

Explore our range of MVHR systems designed with intelligent Summer Bypass functionality to keep your home cool, fresh, and efficient.