July 2016

What is dMEV?

When looking for a fan that is right for you and your family, you might have come across a lot of different acronyms and wondered what they meant. One of the most common acronyms within the ventilation is dMEV. dMEV stands for Decentralised Mechanical Extract Ventilation. This is a form of continuous ventilation that is used within domestic properties.

It was traditionally used within social housing sector and with private landlords, due to pthe fact that it needed minimal input from those living within the property and the cost-effective running rate. It has grown in popularity over recent years as a cost-effective alternative to a whole house system, as many of these units are cheap to run and require minimal input from those living within the property after they have been installed.

dMEV fans are installed in each wet room just like your typical intermittent extractor fan and ventilates the whole property from that room, as with all ventilation systems. dMEV fans are, in many cases, two speed fans, with the lower speed being used as its trickle rate and the higher rate being used for boosted extraction.

The trickle rate of the fan is the flow rate at which the fan is always running at and tends to be at a fairly low flow rate. The rates at which the Building Regulations Part F specify the trickle rate to be are dependent on the following criteria:

When a dMEV fan is being specified for your property, you need to be aware that the minimum flow rate for a dwelling is either the figures found in table 5.1b or 0.3 l/s per m2 of floor area – whichever is bigger. Be aware that the flow rate could increase again should there be more occupants than outlined in note b. below table 5.1b.

When the moisture levels rise within a room, for example when you cook or take a shower, the dMEV fan with a humidity timer function should automatically boost so to swiftly remove the excess moisture from the room. This will help to prevent damp and mould developing within your property and help you maintain a comfortable living environment.

Want to learn more about the range of dMEV fans that you could improve the indoor air quality within your home? Contact Airflow and we’ll take you through our wide range of dMEV fans including the virtually silent iCONstant that guarantees installed performance. Alternatively, you can use our SelectAir service to see which fan is best for you.

Avoiding Installation Horror Stories

We at Airflow love our products and want to provide you with highest quality indoor air and most comfortable living environment as possible. There are instances where you spend a lot of money on a ventilation system, only for it to be installed badly.

You end up with a substandard ventilation system that doesn’t perform as well as it should or even at all. Furthermore, there will likely be no improvement in the quality of air being circulated around your home, and in the most severe cases, there may even be a decrease in its quality. You suffer from this poor install, as you’ve now wasted money on a system that doesn’t do its job and now have to pay for it to be installed properly.

Below you can see some of the poor installation jobs that we have seen on some of the sites that we have visited in the past.

Above shows what happens when the incorrect fasteners are used to connect the flexible ducting to a T-Joint. The duct has split and results in non-performance of the ducting system.

By being coiled, the system pressure is now higher and the fan has to work harder to move the air and the system won’t deliver the performance that was specified.

We also don’t want these bad installation practices to happen. This not only reflects badly on us, as our products aren’t performing as well as they should but more importantly, you aren’t receiving the comfortable, healthy living environment that you deserve.

Because of this, we will now recommend only NICEIC approved installers where possible. This newly launched scheme will see installers assessed to the highest of standards and subsequently audited to ensure that they install our products correctly; thereby ensuring you receive the highest quality, safe, and comfortable indoor air environment.