I dislike Trickle vents

Replacement vents do not automatically have to achieve the 8000 figure for habitable rooms there are some getarounds if you don't have the window space or already have existing vents

Replacement windows and trickle vents | LABC

This guide is intended to help people involved with replacing windows in existing dwellings to understand the 2021 changes to ventilation requirements of the Building Regulations in England. The article provides details on the key changes, along with examples of how compliance can be achieved...
www.labc.co.uk www.labc.co.uk
 
robinbanks said:
Sure, block the vents and then either fit an MVHR or let us know how the battle with black mould goes next year. Personally I'd go for MVHR - one of the best things I've ever bought for the house
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He won’t need one he has rewritten the laws of physics .
 
It's obvious that the jury is still out on trickle vents, and there are lots of knowledgeable people out there who talk very convincingly about their advantages and disadvantages. It does seem to me rather contradictory though, to insist that on the one hand, new buildings should be airtight and on the other insist that they shouldn't be airtight, to insist that a window must conform to certain uvalues and then fill it full of holes so it no longer conforms to those uvalues. Why make sure that thermal bridging is kept to a minimum and then legislate so that a hollow window frame is open to the elements and so becomes a radiator working to disperse heat to the great outdoors?
People continue to have, of course, the option to close their vents (but will still lose heat through the frame) so why not just let them have the option of opening and closing a window instead of opening and closing a trickle vent? It seems to me that some of our lawmakers may have had more persuasive considerations than concern for mould or stale air and I understand that the trickle vent manufacturers were quite keen to be involved in the decision making process. 'Can't help wondering why.
Like Ronniecabers I have considered a mechanical heat exchange system but the cost of retro-fitting one turned out to be prohibitive for me and also a mechanical system, which has 2 sizeable duct fans running 24/7, even though it does recycles heat, perhaps isn't so environmentally friendly after all. Passive ventilation would be a possibility, but that means drilling a hole 100mm+ diameter through the wall of every habitable room in the house direct from the outside when I've just spent thousands of pounds on Celotex! I must have missed something.
Trouble is, I'm ordering my windows tomorrow so I have to decide; trickle vents or no trickle vents! I have a sleepless night ahead.
Thanks once again for everyone's input.
 
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There are things you can do with passive stack too to recover heat, but again a lot of faff to retrofit

My MVHR apparently consumes 0.48kwh a day, but I note that every reading is the same, even though it changes fan percentage on a schedule to set back for night, so it may be at the limits of low consumption for what my energy monitor can detect. I'll see if I can get any more accurate reading out of the manufacturer's IoT dashboard

brucek said:
.Trouble is, I'm ordering my windows tomorrow so I have to decide; trickle vents or no trickle vents! I have a sleepless night ahead.
Thanks once again for everyone's input.
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Well, you can't undrill a hole so I'd say order without and if the urge takes you, drill one in. Maybe ask the window co to supply the vent covers but not drill the holes so it's easier to finish if you go for it

Heat recovering extractor fans exist; not stellar efficiency compared to a dedicated MVHR but you could install them in the moist areas (kitchen/bathroom) and then keep an eye on whole house humidity

Also, take a look at these; http://www.viking-house.ie/fine-wire-hrv.html MVHR without the onerous ductwork
 
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freddiemercurystwin said:
Well legally they're not allowed to do that now are they.
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Apparently they are and do. It's up to the installer to fit or have them fitted. FENSA doesn't approve the windows without a proper ventilation system but I won't be going down the FENSA route anyway since I'm not an approved fitter and I will have al my work inspected by Building Control. Apparently FENSA only states that the windows have been fitted to BC specification anyway so an actual BC inspection means more than a FENSA self certification.
 
Well alright, put it another way you won't (or shouldn't if BC are sticklers) get sign off if an alternative to the vents is not present.
 
BC should NOT being signing that off if you don't have a recognised ventilation ( whether tvs, piv, mhev or airbrick) . IF they do then they will have broken the very Building Regulations they are supposed to uphold and this would make a complete mockery of them. Personally I would check with BC before ordering ( and then be intrigued to hear their answer please ), as by all means you can retro fit vents but it's a pain in the a4se.
As goes the manufacturer I would be surprised if they let you order vents with the window and request no holes, as this could easily open them up to a court case regarding professional liability.
I am not in the least pushing trickle vents , I hate the bloody things and totally agree about rated windows with holes in and how pointless it all is.
 
Thanks for your input again. I'll investigate the MVHR units.
Looks like a combination of trickle vents (with me retrofitting an internal sleeve made from upvc hollow skirting board) upstairs and passive ventilation downstairs is the best way forward. Can't get enough wall height (because of sloping ceilings) upstairs for a passive vent and I don't want to start fitting roof vents. Certainly I wouldn't expect Building Control to sign anything less than is required but I reckon they'll be happy with the combination. I did speak to BC some time ago and was told that I had to do whatever my architect specified (plans were passed a long time ago so I could go back to 2007 regs if I wanted). I've already had the conversation with my suppliers and they will supply windows with/without vents and sell the vents separately. They told me that compliance is the responsibility of the fitter, not the supplier. Not every window in my project needs a vent anyway because some rooms have several windows and (just checked current regs) 5000 mm2 EA vent per room is now what's required, with a total of 5,500 mm2 for the whole property.
Onwards and upwards. Thanks again.
 
Only 5000mm2 ea if other ventilation provide otherwise habitable rooms is 8000mm2 ea.
As goes the plans , when were they passed and when did you start building? As planning only lasts for 3 years
 
You're right, it's 8,000mm2. I'll get there eventually!
Plans were passed back in 2007, but work started in 2008 and was approved by Building Control back then so no concerns on lapsed planning. Recession, illness & Covid all set me back but I'm moving in the right direction again now. Still not setting any completion dates though; these things take time when you're trying to do everything yourself. Building control very happy so far anyway.
 
ronniecabers said:
Get used to Trickle vents I'm afraid... ALL replacement and new upvc windows have to have them fitted under building regulations. Unless of course you go PIV or similiar
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Is this a recent thing ?
ronniecabers said:
Yes, from June 15th this year
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OMG I was seriously considering upgrading my double glazing this year, thanks all in this thread who have opened my eyes, I am not going to waste money on good insulation that some stupid government diktat ruins. No way will the trickle vent manufacturers who inspired this are going to make any money out of me. The DG vendors should have screamed blue murder!! Sorry if this is hijacking this thread but I had to say something.
 
The theory is simple and is justified as the following, quoted from the document linked to at the top of this page:

Replacing the windows is likely to increase the airtightness of the dwelling. If ventilation is not provided via a mechanical ventilation with heat recovery system, then increasing the airtightness of the building may reduce beneficial ventilation in the building.
In these circumstances, it is necessary to ensure that the ventilation provision in the dwelling is no worse than it was before the work was carried out.

The forum is awash with threads about mouldy walls, excessive condensation and other internal damp problems.
 
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