Monsoon Alternate Flow Heat Recovery Fan
Rating: 100 / 100

A single room alternate flow unit that provides fresh, filtered air and extracts humid air without losing heat. It’s ideal for dealing with problem condensation in rooms such as living rooms and bedrooms as it reduces humidity & pollutants.

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Availability: >In stock


RRP £280.00 Ex VAT
£249.00 Ex VAT £298.80 Inc VAT

Single Room Alternate Flow Heat Recovery Unit

The Monsoon Mon-HR Alternate Flow fan brings fresh, filtered air in for 70 seconds and then removes humid air for 70 seconds. As a continuous flow supply and extract fan, it is effective at reducing humidity in single rooms. 

The fan also features a ceramic heat exchanger unit. This heat exchanger collects and retains heat from the extracted air. As the warm air travels across the heat exchange area, it recovers the heat to heat incoming air. This saves you money on your energy bills. The units are also extremely low energy so are very economical to run.

Domestic Supply & Extract Fan

The fan is designed for domestic use and to meet the needs of inhabitants. It is very cheap to run, It is ultra quiet and comes with an attractive fascia. More importantly, the Monsoon Mon-HR allows single rooms to breathe. By exchanging humid air for fresh filtered air on an alternating basis, it reduces humidity levels and pollutants. This helps solve issues with condensation, damp and mould. 

The highly effective heat exchanger unit means it can be used confidently in bedrooms, living rooms, hallways and dining rooms without risking any heat loss or cold draughts.  

A further benefit to this alternate flow unit is that you do not require an additional sensor module. All sensors are built in. The Mon-HR also has different settings to meet your changing needs. 

If you want to use these fans in multiple rooms across your home, you can link up to four units. This allows them to work together to more effectively ventilate your entire home. This includes allowing cross ventilation by running opposite units to alternate supply and extract modes. 

Installing Supply & Extract Fans 

Monsoon Mon-HR Alternate Flow fan ‘through-the-wall’ units are easy to install using a 110mm core drilled hole. Installation requires access to both internal and external surfaces. The unit must be installed by a qualified electrician.

Note: Suitable for wall thickness from 270mm to 500mm.

Permagard - Providing Solutions. Inspiring Confidence. 

If you have any questions around alternate flow units or ventilation in general contact our expert team on 0117 982 3282. Permagard are experts in condensation control and will find a solution to your situation.

You can browse our ventilation products or read our complete guide to ventilating your home.


  • Up to 90% heat recovery with an energy efficient regenerative heat exchanger
  • Cheap to run - costs less than £2 a year
  • 5 year guarantee
  • Three airflow settings to match your needs
  • Tackles condensation and damp issues such as mould growth
  • Can control 1-4 units with the controller (AVAILABLE SEPARATELY), allowing selection of off/on, the speed selection and extract or supply
Model: MON-HR100
Manufacturer: National Ventilation
Packaging: each
Size: see technical data sheet
Coverage: 1 Unit per room
Country of Manufacture: United Kingdom

Need more information?

Speak to our technical experts.
0117 982 3282

Fantastic Product

I built a 15sqm bar in the garden and notice some mould around the skirting boards, plus a high degree of moisture in general. I spoke to the technical guys who were so helpful and they recommended the Monsoon unit. It is very quiet and quite small which looks neat. Since it was installed I have had no more problems, the unit is fantastic thank you

Excellent. Great for rented properties

Having spoken to one of the Permagard technical experts I settled on buying the monsoon heat recovery fan for a rented property with a particular condensation problem. This was easy to install for my electrician and there are no buttons or switches to prevent tenants turning this off which is of importance to landlords. The fan is super quiet and in fact I had to put my ear next to it to even check it was working. I have since bought another one of these. I chose the monsoon over the kair fan because the sensors are all built. I'm now looking forward to a condensation free house, thank you Permagard

Permagard Reply:

Hi Martin, Thank you for leaving such a detailed review, we love to hear that our products are making a difference! The Permagard Team

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