system 3 and 4 are "continuous mechanical ventilation systems" - in order to provide "adequate means of ventilation" as laid down in ADF.
The only continuous system which does switch of is PIV (to prevent overheating of a home due to the solar gain within a loftspace).

The running costs are so negligible its not worth turning off....

Besides, you will generate smells and moisture all year round which needs extracting/removing.

I agree with Damon.

Unless:

A member of the household suffers from hay fever, or
The property is on a busy road where the noise would be Intolerable.

For a 200 m2 property with an EST 'best practice' SFC of 1.0 W/l/s operating at the minimum of 0.3 l/s/m2, the consumption is 60 Watts continuous. Would you leave a 60 W light bulb running continuously for 4 to 6 months?

Also, the filters will require more frequent changes.

GaryB: true, but that I hope is covered by "unless no alternative is reasonably possible" though even then I'd still think about other/future users of the house and have an openable window for them even if I did not open it myself.

Rgds

Damon

Well, more benign then Siberia! B^>

And our heating went off earlier than usual this year, with some support from MHRV on chilly nights, so a definitely energy saver when used carefully in what passes for a British spring/summer...

Rgds

Damon

I never said they were mandatory and never said they replace openable windows.
In fact you are unlikely to get sufficient airflow from any system to give the purge rate provided by an openable window. This causes design issues on noisy sites under PPG24.

The query was whether you should turn off mvhr. Ive tried to offer my knowledge and experience for the reader of this thread looking for factual guidance, esp for new build compliance.
Of course you can do what you like. The regs do state that mvhr is designed to provide continuous mechanical ventilation.
If you have internal wetrooms you dont have the option to open a window so mech vent would be required if you wished to remove smells and or moisture.
You will have to declare to BC which system you intend to employ, how you then use it is upto the owner/user.....

That may be a good reason not to have ducts, as Viking has often said.

My single-room MHRV should also be immune providing I wash/decon the extractable bit as per the instructions, so I have turned it off entirely for now.

Rgds

Damon

Always its all down to interpretation.
System 3 and 4 (which are options for you to provide adequate means of ventilation) are called continuous mechanical ventilations systems (with or without heat recovery).

My dictionary states that "continuous" means: without interruption, forming a series with no exceptions or reversals.

Its down to the user to use how they feel best. As you can lead a horse (or other creatures of a similar nature) to water and all that.

I cant find my copy just now of ADF due to now sharing my office with a baby en-route. However, there are various tables and sections on "trickle" rates based on footprint. and boost rates based on nos of wetrooms.
Again , my interpretation and hundreds of architects, consultants and developers I dealt with interpret this as a continuous background rate and commission accordingly (allowing for infiltration or not as the case maybe).
(you now must produce a commissioning certificate, and ideally show the installer is "competent" via a BPEC course).
If the tenant then turns off the unit the subby, the developer, the architect is "covered" as they have offered a compliant ventilation system - as signed off by building control.

Posted By: TimSmallOne of the guys from Parity Projects said that nearly all (all?) of the multi room heat recovery systems which they've fitted ended up getting turned off by the occupants because of noise-nuisance.

Probably means they don't install them very well then! Some of the issues here are discussed in the attached document. Incidently the author of that document fitted our system and there is certainly no noise nuisance.

Is the noise issue similar to the wind turbine noise issue, if you like/benefit what it is doing for you it is not a problem. Flip side being that if you do not benefit/care then it is a nuisance. Within sensible limits mind.

It struck me that even trickle vents can be closed so why not switch off your MVHR if you plan to open windows. Personally I favour the idea of MVHR controlled by humistats and CO2 detectors with a boost button in case you had a curry the night beforethat way the system runs itself as appropriatte but turns off if you leave doors and windows open in summer (not 2012).

Posted By: joe90 in case you had a curry the night before

do they do a sensor that can detect such odours ?

This is what I said:-
(Unless someone knows of a pong detector?)

Posted By: joe90 with a boost button in case you had a curry the night before" >

But a no1 wouldn't require a boost, where as a no2 might , so joes button would be best

Hi Hairlocks-I got mine from here:
http://www.extractorfanworld.co.uk/vent-axia-heat-recovery-ventilation-sentinel-kinetic-plus-b-1143-p.asp
I got the extra larger spigots at the same time as the kinetic plus. It was a bit of a faff for them to get I think, but it got them the kinetic sale - hence they were keen!
I got extra 2*200mm, and 2*180mm spigots. The 180mm ones came with a foam adapter to expand them up to 200mm. The main unit came first, then the extra spigots a few weeks later.