Ventilative Cooling for Eco Homes in NZ
Ventilative Cooling Techniques That Actually Work in Eco Homes
Ventilative cooling is one of the most effective ways to keep eco homes comfortable without relying on active cooling. Here’s how to do it properly—and when to call in backup from the COLD. system.
What is Ventilative Cooling?
It’s the controlled use of airflow to remove heat from a building—either naturally or mechanically. When designed well, it reduces or eliminates the need for air conditioning while maintaining fresh, breathable indoor conditions.
- Reduces energy use
- Enhances indoor air quality
- Supports passive design principles
Natural Ventilative Cooling Techniques
1. Cross Ventilation
Encourage breezes by placing operable windows on opposite walls. Internal doors or openable transoms can help move air between rooms.
2. Stack Ventilation
Hot air rises—use clerestory windows or skylights to let it escape, while drawing cooler air in from below.
3. Night Purge Ventilation
Flush out daytime heat after sunset. Open high and low windows for a few hours, or automate the process with actuators.
4. Pressure Zones + Shaded Air Inlets
Draw cooler air from shaded sides of the house using planting, pergolas, or vent covers. Use wind pressure differentials to enhance air movement.
Mechanical Ventilative Cooling for Airtight Homes
1. MVHR with Summer Bypass
Set your MVHR to bypass heat recovery at night. Fresh, cooler air is circulated without recovering unwanted heat.
2. Boosted Extract Ventilation
Run bathroom or kitchen fans at low speed overnight to assist airflow. Small boost, big impact.
When Natural Ventilation Isn't Enough: Enter COLD.
Some days are too humid. Some nights are too still. That’s when ventilative cooling needs backup—and the COLD. system delivers.
What Is the COLD. System?
- COLD.W – Water/glycol-based post-cooling coil for hydronic homes
- COLD.X – Direct expansion coil for split-system integration
- COLD.R – Reheat coil to prevent duct condensation after deep cooling
Why Combine COLD. with Ventilative Cooling?
Ventilative cooling works best in ideal conditions. When it’s too hot or humid, COLD. takes over—cooling and dehumidifying the air before it even enters your living space.
- Consistent indoor temperature
- Quiet, invisible operation
- No draft or dry air discomfort
Final Thoughts: It’s All Part of the System
True comfort comes from layering strategies. Ventilative cooling should always be considered in early design—but mechanical backup ensures resilience and performance during heatwaves or high humidity periods.
At BEO Buildingscience, we help you get both right. Let’s design a ventilation and cooling strategy that works even when the breeze doesn’t.
