Continuous Inline Bathroom fan available?

[MarkJohnson]

That achieves nothing.

If the lights are not 100% sealed types they need to be replaced with ones which are.
Firehoods have one purpose - to slow the spread of fire through the holes in the ceiling if there is a raging inferno in the bathroom.

Hi,
The downlighters don't have any obvious gaps. The idea with the firehoods is to create space above the downlighters so I can add (the currently missing) insulation to the loft above the bathroom.
Is that reasonable?

 

[flameport]

Some downlights require space if there is insulation above.
Firehoods are not intended for that purpose however rigid types can also do that.

 

[MarkJohnson]

Might be worth having a look at a PIV system.
Don't know a lot about them other than what I have read

Positive Input Ventilation: The Pros and Cons

Positive Input Ventilation (PIV) units alleviate condensation - but are they the most effective method? Read our guide on PIV units to find out.

www.permagard.co.uk

Nuaire and Vent Axia seem to be the most common makes.

Thanks. I've thought about a PiV and the two main problems seem to to be:
It seems to be mostly a matter of luck where the air gets vented to and
Since it pushes air in from the loft, which is cold in winter, you are left with either a cold landing or get one that uses an electric heater to warm the air (about 200W) which is expensive to run.

So I thought using negative air pressure from the inline extractor fan that needs to replacing anyway would create a pull of warmer air through the bathroom and achieve the same effect.

Despite much searching I can't find an ithevwsll.nline fan with trickle. There are plenty of the ones designed to fit through the wall type where the fan unit is actually on the wall.

 

[RandomGrinch]

Despite much searching I can't find an ithevwsll.nline fan with trickle.

The Envirovent MV160 line appear to have 2 speeds including continuous running...

Envirovent Silent 160 MV Ultra Quiet in Line Fan - SILMV160/100S

The SILMV160/100S is an ultra-quiet in-line duct fan designed for both domestic and commercial applications. It features a patented silent axial motor and is equipped with sound absorbent insulation, making it one of the quietest in-line fans available. The fan is IP44 rated and includes...

www.airconcentre.co.uk

Although wiring up the fan won't be as simple as taking a single switched live from the light switch...

Edited to leave link to item in stock.

...and I haven't found any information directly from Envirovent, to say that it is rated (or not) for continuous operation.

Edit2:

Ok, while a 2 speed fan may be what you require - the description on the website I linked to, actually relates to a completely different product line...

ECO dMEV+ LC | Decentralised Mechanical Extract Ventilation | EnviroVent

The ECO dMEV+LC is a centrifugal extract fan with optimum versatility to operate continuously or intermittently.

www.envirovent.com

Oh well, I tried! Don't trust anything you find on the web!

 

[MarkJohnson]

Clothes drying in a house with poor ventilation and insulation is going to be problem. Definitely put in a continuous extraction in tne bathroom or a timed overrun extractor that always comes on with the light. Even if it doesn't fully resolve the problem you have a defence if they complain to the Council. The bathroom door needs a gap at the bottom if the extraction is going to work more efficiently.

Agreed. Continuous extraction is what I'm trying for but one that will boost the speed when the light is on and a timed delay so it runs in boost mode for 15 mins afterwards. The faulty inline extractor is already a unit with timer so the wiring should be the same (permanent live, permanent neutral, and switched live).

 

[MarkJohnson]

The Envirovent MV160 line appear to have 2 speeds including continuous running...

Envirovent Silent 160 MV Ultra Quiet in Line Fan - SILMV160/100S

The SILMV160/100S is an ultra-quiet in-line duct fan designed for both domestic and commercial applications. It features a patented silent axial motor and is equipped with sound absorbent insulation, making it one of the quietest in-line fans available. The fan is IP44 rated and includes...

www.airconcentre.co.uk

Although wiring up the fan won't be as simple as taking a single switched live from the light switch...

View attachment 331862

Edited to leave link to item in stock.

...and I haven't found any information directly from Envirovent, to say that it is rated (or not) for continuous operation.

Edit2:

Ok, while a 2 speed fan may be what you require - the description on the website I linked to, actually relates to a completely different product line...

ECO dMEV+ LC | Decentralised Mechanical Extract Ventilation | EnviroVent

The ECO dMEV+LC is a centrifugal extract fan with optimum versatility to operate continuously or intermittently.

www.envirovent.com

Oh well, I tried! Don't trust anything you find on the web!

I'd come across the Envirovent range but they said (as per your link) "intermittent OR continuous operation" which makes me think they can do either mode but not both. The other link (dmev) isn't inline as the fan unit would be installed in a wall usually. Thank you for taking the time to do a search but I seem unable to find an inline extractor fan that runs at low extraction rate when "off" but at high speed when the light is on and preferably with a timed function.

 

[MarkJohnson]

The Envirovent MV160 line appear to have 2 speeds including continuous running...

Envirovent Silent 160 MV Ultra Quiet in Line Fan - SILMV160/100S

The SILMV160/100S is an ultra-quiet in-line duct fan designed for both domestic and commercial applications. It features a patented silent axial motor and is equipped with sound absorbent insulation, making it one of the quietest in-line fans available. The fan is IP44 rated and includes...

www.airconcentre.co.uk

Although wiring up the fan won't be as simple as taking a single switched live from the light switch...

View attachment 331862

Edited to leave link to item in stock.

...and I haven't found any information directly from Envirovent, to say that it is rated (or not) for continuous operation.

Edit2:

Ok, while a 2 speed fan may be what you require - the description on the website I linked to, actually relates to a completely different product line...

ECO dMEV+ LC | Decentralised Mechanical Extract Ventilation | EnviroVent

The ECO dMEV+LC is a centrifugal extract fan with optimum versatility to operate continuously or intermittently.

www.envirovent.com

Oh well, I tried! Don't trust anything you find on the web!

I did ring Envirovent and the closest they sell to what I want is the MEV 160. It can switch to high speed when the light is on and switches back to slow speed when the light is off. It has a built in humidistat so the slow speed actually varies from low to high depending on the humidity.
It is 5" not 4" but you can get adapters. It is also about £425 which is more than I was hoping to pay but I'm thinking about it. It wasn't described as quiet or silent so I'm a little concerned it might be noisy when at high speed and the tenant might be tempted to turn it off.

 

[flameport]

You may be wasting your time.

If the tenants won't use the heating, the chances of them leaving an extractor running continuously are pretty much zero.

 

[EFLImpudence]

the chances of them leaving an extractor running continuously are pretty much zero.

... but they will tell you that they do and the condensation is a mystery.