The Vectaire Maxi is a whole-house MVHR (Mechanical Ventilation with Heat Recovery) system designed for residential properties up to 250 m². UK-manufactured to ISO 9001:2015 and 14001:2015, it achieves up to 92% heat exchange efficiency with a peak airflow of 177 l/s and a minimum specific fan power of just 0.40 W/l/s — among the most efficient values available for a unit of this capacity. The Maxi continuously extracts stale, humid air from wet rooms and replaces it with fresh, filtered, pre-warmed air, eliminating condensation and pollutants while slashing ventilation heat losses. It is SAP PCDB Listed and fully compliant with UK Building Regulations Part F and Part L.
92%
Heat Exchange Efficiency
177 l/s
Max Airflow Capacity
Installer Note: A clearance of 200 mm must be allowed on each side of the cabinet for access to the motors. Install vertically in a loft, cupboard, or utility space. The wall fixing bracket is supplied. This unit must be installed and commissioned by a competent person in accordance with Building Regulations Part F. If more than one light switch is used to trigger boost, each must be a double pole switch.
Compatibility Note: The Maxi is compatible with the Vectaire Cool Breeze active cooling module for overheating mitigation (sold separately). Models with humidistat have factory-set handing; confirm left or right drain direction before ordering. Universal handing models can be configured on site.
SAP PCDB Listed — Passive House Certified Option Available. The Maxi is listed on the SAP Product Characteristics Database for straightforward Building Regulations compliance. A Passive House Certified version is optionally available, making it eligible for use in Passivhaus projects. Full specification downloads are available at vectaire.co.uk/downloads.
Key Features
92% Counter-Flow Heat Recovery
The Maxi's counter-flow heat exchanger reaches up to 92% thermal efficiency, capturing heat from warm stale air and transferring it directly to the incoming fresh supply. At a kitchen plus one wet room configuration under SAP 10, the exchanger delivers 92% efficiency at 0.45 W/l/s SFP — meeting the most demanding energy performance targets.
Fully Automatic Summer Bypass
The automatic summer bypass monitors internal and external temperatures and diverts fresh incoming air around the heat exchanger when outdoor conditions are cool enough to provide natural cooling. Setpoints are fully adjustable at commissioning. The bypass operates without user intervention, ensuring comfortable temperatures year-round.
Integral Frost-Stat
The built-in frost-stat proportionally reduces the intake fan speed as the external temperature falls between +3°C and −8°C, protecting the heat exchanger from icing and maintaining balanced operation throughout winter. This is a standard feature — no separate frost protection controller is required.
EC Brushless Motors — Low Noise, Low Energy
High-quality EC brushless motors with forward curved impellers and direct drive deliver efficient, quiet airflow across five speed steps. At 100% (177 l/s) the unit draws just 176 W; at 20% (23 l/s) it uses only 4 W. Breakout sound pressure at 3 m is 38.1 dBA at 100% and 20.2 dBA at 20% — independently tested to BS EN ISO 3743-1:2010.
Independent Variable Speed Control
Each motor has independently adjustable trickle, boost, and purge speeds set during commissioning to match the specific ductwork installation. Boost is activated via 230V switched live from a light switch, remote humidistat (DRH240), PIR (PIRFF), thermostat (THM), or pull cord. The adjustable over-run timer runs from 0 to 90 minutes; purge over-run from 0 to 250 minutes.
EPS Acoustic & Thermal Enhancement
The steel casing incorporates EPS (expanded polystyrene) internal components and foam construction lining, providing both acoustic dampening and thermal insulation around the heat exchanger core. This reduces heat loss from the unit body and keeps in-duct noise transmission low. The epoxy paint finish ensures a durable, clean appearance in any utility or loft space.
Smart Integration & Automation
Factory-set options include 0-10V connections for BMS integration, CO₂ detection, and home automation; a relay for an external pre-heater; a 3-speed selector switch; integral humidistat; and holiday mode (default: 50% trickle speed when unoccupied). Run-time and power outage counters are downloadable via QR code, aiding planned preventive maintenance.
Cool Breeze Compatible
The Maxi is designed for seamless integration with the Vectaire Cool Breeze active cooling module. The Cool Breeze attaches directly to the Maxi's supply air path and uses R290 natural refrigerant to lower incoming supply air by up to 20°C, delivering up to 4.1 kW of cooling capacity without an external condenser. This combination satisfies CIBSE TM59 and Approved Document O requirements for overheating mitigation.
Technical Specifications
| Max Airflow Capacity |
177 l/s (637 m³/hr) |
| Airflow at 50Pa |
163 l/s |
| Heat Exchange Efficiency (max) |
92% (SAP 10: Kitchen + 1 wet room) |
| Specific Fan Power (SFP) |
Down to 0.40 W/l/s |
| Total Power — 100% / 20% |
176 W / 4 W |
| Operating Current |
1.41 A |
| Airflow Speeds (l/s) |
177 / 138 / 99 / 60 / 23 (100–20%) |
| Breakout Sound Pressure @ 3m |
38.1 dBA @ 100% · 20.2 dBA @ 20% |
| Max Operating Temperature |
60°C |
| Frost-Stat Activation Range |
+3°C to −8°C (outside temperature) |
| Boost Over-Run Timer |
0–90 minutes (adjustable) |
| Remote Purge Timer (optional) |
0–250 minutes (factory preset: 15 min) |
| Filter Grade |
G3 (disposable, easily accessible) |
| Dimensions (W × H × D) |
758 × 727 × 649 mm (incl. spigots) |
| Weight |
37 kg |
| Duct Connection Diameter |
Ø149 mm (four spigots) |
| Casing |
Steel sheet, epoxy paint finish, EPS lining, foam construction |
| Heat Exchanger Type |
Counter-flow |
| Motor Type |
EC brushless, direct drive, forward curved impellers |
| Supply Voltage |
230V AC |
| Warranty |
5 years (1 year parts & labour, 4 years parts only) |
| Certifications |
SAP PCDB Listed · CE Marked · ISO 9001:2015 · ISO 14001:2015 · EU RoHS · IEC60335-2-80 |
| Sound Testing Standard |
BS EN ISO 3743-1:2010 (independently tested) |
Models Available
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WHHR Maxi/BY — Bypass, universal handing
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WHHR Maxi/BLH — Bypass, left drain, humidistat
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WHHR Maxi/BRH — Bypass, right drain, humidistat
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Maxi BY+LCD — Bypass, universal, integral LCD commissioning unit
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Maxi+LHHLCD — Bypass, left drain, humidistat, integral LCD
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Maxi+RHHLCD — Bypass, right drain, humidistat, integral LCD
Frequently Asked Questions
What is the difference between the Maxi and the Maxi Plus BY?
The Maxi is rated for properties up to 250 m² with a peak flow of 177 l/s and up to 92% efficiency. The Maxi Plus BY handles larger homes up to 400 m² with a higher peak flow of 238 l/s. Both feature summer bypass and frost-stat as standard. The Maxi pairs with the Cool Breeze cooler; the Maxi Plus BY pairs with the Cool Breeze Plus.
Can the Maxi be used in a Passivhaus project?
Yes. A Passive House Certified option is available for the Maxi, making it compliant with Passivhaus Institut requirements. This is typically required for any dwelling targeting Passivhaus certification, where airtightness and heat recovery standards are significantly more demanding than standard Building Regulations.
Is the Maxi suitable for new-build and retrofit installations?
Yes. The Maxi is designed for both new-build and retrofit applications. Its compact footprint (758 × 727 × 649 mm including spigots) and vertical loft/cupboard orientation make it adaptable to most existing properties. Casavent provides full design support including CAD drawings, airflow calculations, and commissioning guidance for both project types.
How is the Maxi commissioned and balanced?
Each motor speed (trickle, boost, purge) is independently adjusted at installation to match the calculated airflow requirements of the ductwork system. An optional integral LCD or remote LCD commissioning unit is available for precise flow balancing. For best results, Vectaire recommends using rigid ducting and following the SAP PCDB tabulated configurations.
What accessories and support does Vectaire offer with the Maxi?
Vectaire can supply the complete system including filter cassettes, silencers, fire dampers, air valves, ducting, outside grilles, and wall cowls. A ventilation design service is available to optimise unit selection and duct layout. Installation, commissioning, and ongoing maintenance services can also be arranged. Casavent provides independent advice on system design and full end-to-end project support.
