Fairhaven H&V Services - Moira, Northern Ireland

Fairhaven H&V services have been supplying ventilation equipment to the construction and industrial sectors in Northern Ireland since 1990. We are distributors and agents for some of the leading manufacturers in the mechanical and natural ventilation market, and our comprehensive range of products means we can provide solutions to practially any ventilation requirement.
(028) 92 611648

Hybrid Thermal Mixing




Hybrid Ventilation Systems seek to provide the ideal trade-off between the controllability of mechanical ventilation and the low running costs of natural ventilation.  An integral fan gives the system the ability to provide guaranteed levels of fresh air to the ventilated space, whilst mixing it with recirculated room air to maintain acceptable supply air temperatures without any supplementary heating.


Monodraught’s Hybrid Thermal Mixing (HTM) solution has been developed primarily for schools, to comply with the latest Facilities Output Specification (FOS) for the Priority Schools Building Programme (PSBP) in England, but is suitable for a range of other applications including offices.

Our hybrid ventilation system is designed to provide natural ventilation, hybrid ventilation, secure night time cooling and boosted levels of ventilation during summer. The HTM FS systems are designed to be installed above a suspended ceiling or within a ceiling raft and to work in conjunction with natural ventilation provided by manual or automatic windows.

HTM is constructed from composite panels providing high levels of acoustic attenuation and along with its low noise fan it meets BB93 and priority school building programme (PSBP) facility output specification requirements.

HTM exploded view


Why choose HTM?

  • HTM is able to provide the ideal environment to school classrooms/ areas, whilst delivering lower capital and potentially lower running costs than traditional MVHR systems.
  • HTM is designed to provide mixed tempered air during winter, boosted levels of ventilation during summer and secure night time cooling, thus overcoming the shortfalls of 100% natural ventilation strategies.
  • The HTM system can work on its own or in conjunction with natural ventilation provided by manual or automatic windows/louvres, and can be used in single sided or cross flow ventilation strategies.
  • Integral fully automatic controls ensure optimal performance without any user intervention


Monodraught® HTM systems have exceptionally low specific fan powers and feature an intelligent control system, which is supplied as standard, with full data logging facility, temperature control and CO2 control. The system switches between operational modes dependent on season, external/internal temperature conditions and indoor air quality (IAQ). With the optional BACnet module, each unit has the ability to output key performance data to a central BMS.

General Description

Hybrid Thermal MixingTwo versions of Monodraught’s HTM system are available, the HTM F and the HTM FS. The “F” type has been designed to have one unit per classroom, and the “FS” type two units per classroom. The HTM F system is able to produce 350 l/s of daytime ventilation and 530 l/s for night purge ventilation when required, while the HTM FS system is able to produce a daytime hybrid ventilation rate of 180 l/s (SFP 0.14) per unit and night time ventilation rate of 250 l/s (SFP 0.22) per unit.

A powder coated steel frame makes the system robust and easy to install This frame supports a body constructed from specialist acoustic panels which when combined with a low energy fan means that the systems maximum daytime operation sound level is well below 35dB.

The low leakage external damper is integrated within the system and has a U-Value of 1.2Wm2K and when combined with the internal damper allows the system to supply tempered fresh air throughout the year.

For more information, including a CPD seminar on Natural Ventilation including Hybrid Thermal Mixing, contact Fairhaven or visit https://www.monodraught.com/products/hybrid-ventilation