New Zealand’s new-build townhouses are warmer and tighter than ever. That is great for energy efficiency, but it also creates a growing problem: retained heat with nowhere to go. Headlines calling modern homes a sauna without the fun captured a genuine issue for many owners. The brief to builders and developers is now clear: deliver homes that are efficient and comfortable all year. Mitsubishi Electric Lossnay mechanical ventilation with heat recovery is a practical way to meet that brief.
Modern construction locks in heat gains from people, appliances and sun. In the Bay of Plenty that can mean long, humid summer evenings where indoor temperatures refuse to drop. Key drivers include:
• Airtight envelopes that cut draughts but also trap warm, humid air.
• Urban density with shared walls and limited cross-ventilation.
• Warmer seasons that push older design assumptions beyond their limits.
• Regulatory gaps where energy clauses emphasise insulation, yet do not specifically mitigate overheating in occupied rooms.
Local bylaws can compound the problem. Window opening limits for safety, traffic noise, security and privacy all encourage residents to keep windows shut, especially at night. The result is stuffiness, poor sleep and unhappy occupants.
Lossnay is Mitsubishi Electric’s heat recovery ventilation (HRV) platform designed for balanced, continuous air exchange. Stale indoor air is extracted while the same volume of fresh air is supplied from outside. A high-performance Lossnay core transfers heat and moisture between the two airstreams so you keep the comfort you have already paid to create.
• Pre-cooling and pre-warming
In summer evenings, the cooler exhaust air helps temper warmer incoming air; in winter it works in reverse to retain warmth. This reduces load on heat pumps and improves perceived comfort.
• Automatic Free Cooling mode
When outdoors is cooler than indoors, Lossnay can bypass the core to flush the home with fresh, cooler air while extracting hot, stale air. Ideal for homes that heat up through the day and need a quick evening reset.
• Cleaner, healthier air
Continuous exchange helps manage CO₂ build-up, odours and humidity. That makes bedrooms and internal rooms feel fresher and reduces the conditions that encourage condensation and mould.
• Energy-efficient by design
Because the system recovers heat that would otherwise be wasted, you get ventilation without the usual penalty to running costs.
• Smart control and maintenance
Optional Lossnay Wi-Fi Control lets you monitor temperatures and fan status, automate free-cooling windows, and receive filter-clean reminders so performance stays on point.
• Flexible installation
Compact, ducted models suit new builds; other variants can be retrofitted during renovations with carefully routed short duct runs. Zoning strategies allow priority to bedrooms at night and living areas by day.
• Night-time comfort without open windows
With free cooling and balanced airflow, many households can reduce reliance on open windows after dark an advantage where noise, security or sea breezes are concerns.
• Lower cooling demand
Pre-cooled supply air reduces the spike that otherwise hits your heat pump at 9 pm, improving running costs and stabilising temperatures on muggy Bay evenings.
• Better internal rooms
Many townhouse layouts include middle bedrooms or studies with limited openings. A Lossnay supply to these spaces turns them from stuffy to usable.
• Compliance-friendly
Good mechanical ventilation supports healthy indoor air while you still meet fall-prevention, noise and privacy constraints. It also aligns with future-proof expectations as codes and buyer awareness evolve.
• Right-size the airflow to occupancy, not just floor area. Bedrooms need night-time air change; kitchens and laundries need targeted extract or higher rates.
• Short, insulated duct runs to maintain efficiency and minimise noise.
• Thoughtful intake and exhaust placement away from driveways, flues and salty spray.
• Integrate with heat pumps so heating and cooling work with, not against, the ventilation schedule.
• Simple user presets such as Summer Flush, Quiet Night and Winter Recover to encourage daily use.
1. Site assessment and heat-gain review orientation, glazing, shading and internal loads.
2. Airflow and ducting design with a tidy ceiling or cupboard plant location.
3. Quoted options for standard, boosted or zoned control, plus filter and service plan.
4. Professional install by our Mitsubishi-certified team, followed by commissioning tests.
5. Handover and training including app setup and filter care.
Typical installs are completed in a day or two for straightforward layouts; retrofits may take longer where access is tight.
• External shading on west-facing glazing, light-coloured window treatments and correct low-E glass selection during build or renovation.
• Set realistic heat-pump schedules to avoid late-evening overshoot.
• Seal obvious infiltration gaps so the ventilation system, not random leaks, controls airflow.
Overheating will remain a challenge as our climate warms and urban density increases. Lossnay heat recovery ventilation provides a robust, scalable answer: fresh air when you need it, energy savings when you want them, and quieter nights with the windows closed.
Bay of Plenty Heat Pumps specialises in Mitsubishi installations across Tauranga, Papamoa and Mount Maunganui. If your townhouse runs hot after sunset or feels stuffy in the mornings, book a consultation. We will size the right Lossnay system, integrate it with your heat pump, and give your home the year-round comfort it was designed to deliver.
We are your local heat pump and air conditioning agents. We provide installation and maintenance services for a wide range of Mitsubishi heat pumps in Tauranga, Papamoa, Mt Maunganui and Bay of Plenty-wide.
327 Matakokiri Drive
Tauriko, Tauranga, 3110
Unit 12
