Diffusion COVID-19 customer communication

By John Molloy on April 2nd, 2020

The effects of the Covid-19 global pandemic have seen devastating consequences for individuals, families and businesses all over the world. Throughout this time, we have remained operational and have been working hard to ensure our employees have been working safely and in-line with Public Health England guidance. However, given the significant shift in construction activity over the course of the final days of March, we have now taken the unfortunate decision to close our operations for a period of 3 weeks, effective April 01st, targeting to re-assume our operations as normal by April 22nd.

During this period of closure, our non-manufacturing teams will still be on hand to support you with any question, concerns or advice that you need and we are still handling sales enquiries and issuing quotes remotely.

Please contact us the normal way or through or by emailing:
Cooling Sales – cooling@diffusion-group.com
Heating Sales – heating@diffusion-group.com
Spares – spares@diffusion-group.com
General Enquiries diffusion@diffusion-group.com

We will endeavour to come back to you as soon as we can.

Coronavirus (COVID-19) Statement

By Oliver on March 17th, 2020

The senior leadership at Diffusion are continuously assessing the significant challenges and dynamic situation posed by the Coronavirus (COVID-19) and are actively developing mitigating actions to protect the health and wellbeing of our employees and customers whilst ensuring the continuity of supply for our products to the market is maintained.

We are following the advice and direction given by the UK government and are putting in place plans to ensure that all our teams and business services are protected as far as possible by restricting travel between our UK sites and ensuring that where possible our digitally enabled teams can continue to support our customers remotely.

Our supply chain is robust and the actions taken earlier this year surrounding the challenges in China are not impacting our ability to manufacture our products or deliver our services and  to ensure that we can continue to supply the market every effort is being made to increase the output of our production facilities to ensure stock availability can be maintained. 

Whilst the situation is dynamic and develops everyday our teams are currently fulfilling orders and working to our normal hours of business. Should the situation change significantly we will update you via our website.

Heating and Cooling Solutions Guide

By John on May 5th, 2016

Our latest Heating and Cooling Solutions Guide (PDF) are now ready to download – with customer examples along with manufacturing, R&D and quality information –  everything you need to make the right choice in Heating and Cooling solutions.

Click here to download or visit our Brochures section in the Product tab on the main menu.

Not all fan coil units are made the same!

By Oliver on January 16th, 2015

20 Fenchurch Street

20 Fenchurch Street

Diffusion recently supplied over 2000 of their Eco H270 ec/dc fan coil units to the ultra-modern 20 Fenchurch project, nicknamed the Walkie-Talkie because of its distinctive shape.

The joint-development between Land Securities and Canary Wharf Group specified an extremely low specific fan power (SFP) requirement of 0·19W/l/s.

This specific fan power of 0·19W/l/s was to be achieved at an external system pressure of 30 Pascal, and at NR35 with all units running.

Project specific witness testing demonstrated that specific fan powers of 0·14 to 0·17W/l/s would be achieved, and all accomplished within the NR35 noise requirements on standard model selections without oversizing.

Diffusion provided Volumetric, Acoustic and Thermal performance factory witness testing to Land Securities, Canary Wharf Group, Hilson Moran, Chapman Bathurst, Atelier Ten and MH Associates; demonstrating that all unit selections met or exceeded the specified requirements.

Fan coil performance validation at Diffusion is conducted in accordance with:

BS 848-1, BS EN ISO 5801 Air Volume flow rate.

BS 4856-4  Acoustic Performance.

BS 4856-3 Thermal Performance.

The superior SFP figures achieved with standard selections by Diffusion’s Eco H270 ec/dc fan coil clearly demonstrate the benefits of combining carefully considered components and the results of working sedulously with leading fan and motor manufacturers to provide a more efficient product.

Diffusion fan coils – not all fan coil units are made the same.


Eco 270 Range

By Oliver on March 27th, 2014

The new Eco fan coil range from Diffusion is probably the most energy efficient fan coil range ever.

With energy savings of up to 25% the new Eco 270 ECDC Fan Coil offers industry leading specific fan powers at typical selections without any additional cost to the product.

Diffusion High Efficiency Low SFP Eco Fan Coil Unit Range.

With ever increasing energy costs, the saving of energy and the design of energy efficient buildings are now paramount within the HVAC industry. To enable the design of fan coil systems that provide the scope for much improved energy efficiency, Diffusion, by using the very latest ecdc fan technology, have developed a unique energy efficient, 270 mm deep, ecdc fan coil unit.

ECO 270 Range.

This new ECO range of units offers extremely low Specific Fan Powers at typical fan coil duty and air volume selection points.
Specific Fan Powers below 0.2 W/l/s can be achieved at typical NR35 duty and airflow selections with no increase in unit size or cost over our standard ecdc 270mm deep fan coil unit range.
Specific Fan Powers below 0.15 W/l/s can be achieved depending on the unit
duty/air volume selection point.
The new ECO unit range offers significant improvements in SFP, typically 20% (on a like for like unit basis), over existing ecdc fan coil units currently available.


  • Incorporating Leading ec/dc Motor Technology.
  • ErP Directive 2015 Compliant.
  • Low Specific Fan Powers.
  • Infinite Fan Speed Control.
  • Performance at System Pressures Up To 50 Pa.
  • Independently Established Performance Data.
  • Lifetime ‘eco’ filter.

See more:

Eco 270 Page

New Eclipse Air Curtain

By Oliver on February 3rd, 2014

DSC04090The Diffusion Eclipse recessed air curtain has been designed for a vertical concealed application where the client does not want to see a unit within the area. The unit shall be vertical mounted within a recess/bulkhead construction only showing the discharge & the optional return air grille.

The chassis shall be manufactured from heavy gauge galvanised mild steel sheet, with burr free edges and a natural finish, formed and strengthened to provide a rigid and distortion free construction.

Diffusion has recently supplied two Eclipse air curtains for a vertical concealed installation at 2 Waterhouse Square (Pictured above), where they have been discreetly hidden behind the reception walls, with only the discharge air grille on show. The air curtains are mounted on both sides of the main entrance and quietly ensure a comfortable environment within the elegant reception lobby.


  • Concealed installation.
  • Compact design.
  • Available in electric, LPHW or ambient.
  • Grille can be supplied in a large range of colours.
  • Energy saving controls option available.

Please download the Eclipse literature for more information.

You can also download our Air Curtain Selection Guide  for more information on all of our other Air Curtain Products.

Challenging Times Promote Innovation

By Oliver on June 3rd, 2013

eco-friendly-decorating-budget-wise-home-1200x1600As Diffusion enters its 53rd year in business like everyone else we have seen  several years of difficult trading in dire market conditions, business has been challenging. However as is the case difficult times often promote great ideas,  innovation and technical advancement.

At the beginning of the recession as a way to improve our efficiency and  competitiveness we invested heavily in new plant and manufacturing systems which has enabled us to produce a better quality product at a reduced cost which in turn has allowed us to compete positively both on quality and price.

Importantly at the same time we have invested in research and development, both in facilities and people. During this time we have developed several new products. Particularly the Solent fan coil specifically designed for high end residential projects and first used to supply the    prestigious One Hyde Park project. The Solent is now being supplied to numerous residential projects including the Shard residential along with our standard Fan Coils for office areas.

Our most exciting development at Diffusion is the new Highline 270 Eco fan coil unit.  Simply this fan coil is significantly more energy efficient than anything else currently on the market, saving up to 25% energy. The innovation is in the fan technology i.e. Sfp reducing from 0.2 to 0.16 for most individual FCU selections. The really good news is that this innovation comes at no extra cost benefitting our customers and end users.

The new 270 Eco fan coil will be available from April 2013. Please click here for more information on the new ECO 270 Range. To herald the new unit Diffusion will be running a series of in-house CPDS designed particularly to help younger engineers achieve a greater understanding of fan coils in the built environment.


One Hyde Park, London

This site in your language – an experiment

By John on July 12th, 2012

We have enabled this site for real-time translation into more than 60 languages, thanks to Google Translate.

To translate a page, use the “Select Language” dropdown just below the search bar at the top right corner of any page.  Google will translate the page, and any subsequent pages, into your chosen language.  Translation may take several seconds.

We would be interested to know if you find this facility useful.  Please leave a comment on our contact page.  Experts can also submit translation suggestions by hovering over translated text and following Google’s instructions.

Unfortunately we’ve found that Internet Explorer V8 may experience intermittent problems.  We’ve raised these with Google, but reloading (refreshing) the page often works.

A Sound Investment

By Oliver on January 3rd, 2012

Highline 270ec Fan Coil Independent Acoustic Testing
(In accordance with BS 4856 part 4:1997 and BS 4196 part 1:1991)

Diffusion’s Highline 270 range of waterside control ceiling void mounted fan coils having been supplied on numerous projects since 2008 now form a substantial cornerstone for the business, combining the success of this product with Diffusions commitment to provide the most accurate and valuable information on all its products made the decision to undertake independent acoustic testing of the Highline 270 range was an obvious one.

Employing the services of Sound Research Laboratories (SRL Technical Services Ltd) at their UKAS accredited laboratories in Suffolk; all models within the Highline 270 range, covering volumetric air flow rates from 60 ls-1 to 700 ls-1, have now been tested at external static pressures from 10Pa to 50Pa.
Installations and measurement procedures for the testing were conducted in accordance with BS 4856: Part 4: 1997, (Determination of Sound Power Levels of Fan Coil Units, Unit Heaters and Unit Coolers using Reverberation Rooms), with measurements being taken to BS 4196: Part 1:1991, (Sound power levels of noise sources. Precision methods for determination of sound power levels for broad-band sources in reverberation rooms).

The independently established Inlet and Case radiated SWL’s and Discharge In-duct SWL’s can now be provided as part of our technical submittal, affording confidence in the accuracy of data required when any acoustic analysis or assessment is being undertaken.

Furthermore by utilising Diffusion’s own acoustic test rooms we offer the facility to set-up and test for individual project configurations; thus providing more specific acoustic data for individual NR modelling assessment.

Diffusion website update – all roads lead to .com

By John on April 18th, 2011

Today we have standardised our web presence on the site you are on now, www.diffusion-group.com. If you try to access www.diffusion-group.co.uk you will be sent here. We’ve tried to make the switch-over as painless as possible, and all the information on the old site and more should be available on this one. If there’s anything you can’t find, please call us or drop us a line – all contact details, and a contact form, are here.

Thank you,

The Diffusion Web Team