Part F 2021 Ventilation. How it changes window installations

Photo of author

Nick Dardalis

Updated on

When it comes to air quality in dwellings and other buildings, Part F 2021 Ventilation is part of the wider range of Building Regulations. In simple terms, Part F 2021 requests adequate means of ventilation provided in buildings whether by mechanical or natural means.

Also known as Approved Document F, these Building Regulations ensure buildings have a constant flow of clean and fresh air, protecting against moisture, poor quality internal environments, condensation and mould. It’s already well known that condensation and poor indoor airflow is not good for health.

An brief overview of Part F 2021 Ventilation

Part F is the Building Regulations Document covering ventilation. During the life of Part F, there’s been confusion and misinformation on what homeowners understand about these requirements and whether some installers have been responsible for making sure the installation complies, although many of course have. As well as this, more studies since the introduction of Part F, arguably make many parts of it seriously due for review.

Part F Ventilation, has for years, stipulated effective means of ventilation dwellings. The current Document F was amended in 2010 and 2013 with the current changes made public in December 2021 and coming into force in 2022.

The full version of the latest 2021 Edition of Part F mentions that the energy efficiency measures carried out in existing buildings, as well as Part L Building Regulations for new build projects, can cause dwellings and buildings to be under-ventilated.

This latest amendment takes the previous requirements for ventilation and makes them more stringent.

As we understand it, Part F Ventilation aims to make ventilation requirements simpler. At the same time, it tries to align other factors such as airtightness. All of this has come about after a Government review of ventilation and indoor air quality in new homes. The results showed a tiny proportion of the eighty homes tested around the UK actually complied with Part F Ventilation as it presently stands.

Why ventilation in homes is important

Building Regulations Part F for new building projects or extensions can be forgotten about but it’s actually quite important and not just because it’s a legal requirement.

Everyone wants well-insulated homes and choosing energy-efficient windows and doors helping lower heating bills. We’ve concentrated so much on the energy-efficiency message but possibly overlooked airflow and airtightness.

Saving energy through building materials with great insulation is a positive thing. The downside of more energy-efficient and better-sealed homes is the lack of fresh air and condensation as a result. Part F, therefore, aims to provide ventilation and the removal of vapour.

What are the new changes with Part F 2021?

part f ventilation building regulations

With the quality of air in the home being important and recognising that modern windows make buildings more airtight, there are some changes to Part F 2021 covering Ventilation.

Just like the current requirements on vents in windows, if the existing windows being replaced have background ventilators, the replacement windows should include these too. At the same time, the trickle vents must not be smaller than those in the outgoing windows and have some manual or automatic control.

Change. Where existing windows being replaced don’t have trickle vents, ventilation must be no worse than before. If so, the new windows will need trickle vents.

Habitable rooms minimum 8000mm2
Kitchen minimum 8000mm2
Bathroom 4000mm2

Also available in the official document is information about additions of habitable rooms to existing dwellings, ventilation requirements for conservatories and orangeries, adding wet rooms and kitchen and bathroom refurbishments.

What the Part F 2021 changes mean

The window industry anecdotally at least, doesn’t like trickle vents. Homeowners have mixed no or mixed feelings about them. Anyone buying a new build home in the last decade or so would have these installed in their windows. Occupiers of old flats or social housing would have experienced some of the bulky types that sit on top of the glass unit. Trickle vents have been a part of windows and doors for many years already.

As a website, and despite the complications and conflicts with other Building Regulations, we support these changes. Air quality in the home is very important for health supported by extensive studies carried out. That said, there are challenges to Part F 2021 and questions to answer.

Putting trickle vents in all windows and doors adds to the manufacturing cost and selling prices. Trickle vents increase window sightlines at a time when slim sightlines matter a lot to customers.

Then there are questions over increased heating costs to heat the fresh and cooler air from the trickle vents. How big an issue this really is is subjective as trickle vents aren’t designed to make a room cold, even if some perceive they might.

Some will argue against or mention the unwanted noise entering the property as a result of an open vent. There are ways to improve the acoustics of windows and doors with suitable glazing.

These ventilation requirements to Building Regulations have been in force for some time already. Now they’re just different.

With changes to Document L (Conservation of Fuel and Power) coming in 2022, there’s an obvious question about the role Part F 2021 plays and it’s logical to assume ventilation conflicts with sealing and energy efficiency.

How Part F Ventilation affects manufactuers and installers

Believe it or not, there are still several systems on the market, especially sliding and slide and stack doors that don’t come designed for trickle ventilation.

Some manufacturers took the decision to leave the issue of ventilation to the builder and homeowner as their products are intended for new extensions. Other brands in the UK are European systems where trickle vents aren’t needed or even known. These haven’t even been designed for trickle vents as a result, despite selling well here.

For residential windows, there’s little to change from what has been available for years. Some independent systems for doors in extensions will continue to cite the need for other means of ventilation. The obvious question is will they bother telling the customer or leave it until Building Control visits the property.

But for the majority, there isn’t a significant product change, but certainly a mindset one in giving the right information to the customer.

Part F 2021. Summary and Conclusion

trickle vents in new white windows

Installers must be professional and ethical and overcome their own prejudices regarding trickle vents. Demonstrating knowledge and respect for Building Regulations is one way of adding value to any business. They should also be aware of the other Building Regulations relating to windows and doors.

For years the issue of trickle vents has been glossed over, ignored and many installers continue to have a rather obsessive view of what is essentially a component on top of a window or door that actually provides health benefits.

For homeowners, it’s an acceptance that trickle vents are likely to be something they’ll have to learn about and an essential part of their new build or refurbishment project. There’s lots of information now available about the benefits of clean air and how it also helps with reducing condensation inside the home.

The changes to Part F 2021 are happening as are changes to Window Energy Ratings, Part Q for Security and even Part S mitigating the risk of overheating for new dwellings in England and Wales. There is always going to be some clash between existing and new regulations.

For windows and doors, homeowners need to know that trickle vents have been designed into the vast majority of aluminium, PVCu, timber and hybrid products for years already. There’s the option of an add-on profile at the top of the door or window frame housing the trickle vent. Well made, trickle vents are neat and don’t detract too much from the aesthetics of the product. The benefits they provide outweigh aesthetics.

Providing expert help to homeowners and trade professionals since 2010




Get Free help finding the right products from the best suppliers

16:42 30 Oct 23
Nick responded incredibly quickly to my enquiry (on a Saturday too!), and was able to offer invaluable advice on both aluminum systems and manufacturer / suppliers. Thanks Nick!
chris steerchris steer
16:18 09 Oct 23
Had a meeting with Nick during the grand designs show. Was extremely helpful and professional would highly recommend
Chris WesthorpChris Westhorp
19:55 13 Sep 23
Extremely helpful with pointing us in the right direction to find the products we required and suggesting firms that could reliably fit them.Nick was quick to reply and very detailed in his advice.Highly recommend reaching out to them.
Cathy GreenwoodCathy Greenwood
07:03 11 Sep 23
Update - A second email to nick for help on bifolds resulted in a detailed informative reply even on a Sunday ! This guy is so knowledgable and helpful .I approached Nick for an independent view on sliding doors v bifold and the different brand options . His reply was extremely detailed and prompt and allowed me to navigate this often confusing world in a much more informed way . Thanks so much Nick
Anthony CraigAnthony Craig
12:45 05 Sep 23
This is a must site for anyone looking for advice. Great service and very quick answers to questions. Nick has been of great help quiding us through the maze of aluminium products. Thank you
Philip DuffieldPhilip Duffield
20:24 26 Jul 23
I contacted Nick @ ATS for guidance on what aluminium sliding door systems would be suitable for an opening in an extension that is going to be both wide and tall. He came back really quickly with very detailed and incredibly helpful advice. He is clearly extremely knowledgeable about the systems on the market and their respective features and capabilities. If you’re feeling a bit lost by the overwhelming range of choices out there, I’d definitely recommend contacting him.
Dariush HekmatDariush Hekmat
17:25 19 Jul 23
Nick's advice is great. He is always quick to respond and spends time on responses, which really help to make an informed decision.
Alan FosterAlan Foster
07:51 12 Jul 23
Absolutely fantastic. Asked for advice about replacing Crittall (?) windows late last night and early this morning received 3 great suggestions and contact information for suppliers
Rachel LauRachel Lau
09:24 16 Jun 23
Fantastic website full of valuable and pragmatic advice about product selection and comparison: no other website gives information like this. Truly written for public interest. Don't hesistate to reach out to Nick via the mailing system. He responds very quickly, is friendly, and has very sound and high knowledgable advice. I have already shared this with my friend planning her own grand design.
guard Charlieguard Charlie
12:28 14 May 23
I emailed this company just on the off chance they could help me with new magnetic sliders for my patio door. They were not able to supply those but were so very helpful providing me with the name of a company who could. I am so very grateful at the great service. Dare say customers must be very happy. thank you so much.
Benjamin LewisBenjamin Lewis
10:06 04 May 23
Nick is very helpful indeed. Extremely knowledgeable on bifolds which was in relation to my query. Great website as well, some very useful articles. Particularly appreciated the article that lists all the major bifold options in order of their sightlines! Thank you!
P JonesP Jones
08:07 15 Apr 23
I asked Nick some questions about an installation we were considering and he replied within hours with some very useful suggestions that will probably lead us to using a different make and supplier. Thanks, Nick. Great work.
Nicholas WallNicholas Wall
13:18 02 Apr 23
Looking for fair and honest expert advice on all aspect of aluminium windows and doors? These guys will arm you with all the information you need to make the RIGHT choice in a highly complex, crowded marketplace. post a question and you will get a very quick professional answer you can rely on being based on fact. Thanks guys!
Giorgia SiriacoGiorgia Siriaco
16:25 21 Mar 23
After a lot of research to find doors that would meet our unusual size requirements and feeling increasingly uncertain about the best way to spend our small budget, I stumbled on the ATS website, and I'm so glad I did! I contacted ATS to request advice and Nick promptly replied with a wealth of information, providing us with options and relevant contact details. I only wish I'd found them sooner!
Carol NortonCarol Norton
10:01 17 Mar 23
I've been so confused about how to achieve the look I'm after, and going round in circles with various window/door companies, trying to get away from the huge chunks of plastic currently around my windows. I didn't expect an email to a company found through a Google search to really help - but I was desperate, so I tried. I'm SO glad I did. Finally I have clear explanations from ATS of where I've been going wrong, exactly what I'm looking for, and a list of local companies that might be able to provide it! The response has excelled my expectations and I feel as if I'm finally inching closer to a home with which I'll be happy and comfortable: thank you.
David NunnDavid Nunn
20:54 14 Mar 23
It is rare that I write reviews, however after my very positive communication with Nick - enquiring about suitable slim sash aluminium windows for my project, I felt that a review was definitely warranted. I can reinforce the many positive reviews posted so far, Nick was very quick to respond, providing comprehensive detail, with excellent independent advice.In summary, great service, thank you Nick.
Chantal AuerbachChantal Auerbach
13:04 09 Mar 23
Nick from Aluminium Trade Supply was incredibly helpful informative and pleasant to deal with. He responded quickly to emails and was very knowledgeable. Highly recommend being in touch with Nick if you are considering new aluminium windows or doors.
Lee JonesLee Jones
20:21 22 Feb 23
I dropped Nick at Aluminium Trade Supply an email re high security slim sightline bi-folds and their alternatives and he responded that quickly (and so comprehensively) that I felt bad I’d not paid him for his time!Nick Sir your product knowledge is outstanding and you are providing a level of service that goes wayyyy above and beyond expectations. I’ll definitely make sure I mention Aluminium Trade Supply to anyone I encounter looking for a fenestration solution 🙏🏼
15:13 13 Feb 23
We are looking to replace some old UPVC patios doors with aluminium ones. The ATS website is a great source of advice in an area where clear information is sorely lacking. Having used the website, I then followed this up with a number of specific questions relating to our search, and Nick came back very quickly with clear, detailed and very useful advice.I have been very impressed with both the website and with Nick's advice. My only regret is that I didn't come across ATS before replacing various windows in 2021 - I'm sure it would have saved me a lot of grief and money! Thanks again Nick.
Azza McCabeAzza McCabe
17:47 01 Feb 23
So impressed with this company.Responded to my query quickly andgave valuable advice. Nick was extremely helpful and we were able to move forward with our project.
Adri LoloçiAdri Loloçi
11:21 08 Jan 23
Nick was super fast to respond and provided some great recommendations. I would recommend this website to anyone looking to find bifold or sliding aluminium doors.
Stephen HoustonStephen Houston
16:16 03 Jan 23
Looking for aluminium crittall style internal door and external patio French doors. Noted good reviews and thought would ask for advice. Comprehensive reply with excellent independent advice and lists of fitters who could provide products and installation. Great service.
Inga GeachInga Geach
08:25 21 Dec 22
Nick from Aluminium Trade Supply has been extremely helpful with navigating the jungle that is aluminium glazing for our upcoming extension project. His advice was prompt, detailed and always impartial. Very grateful for your input, thanks Nick!
Amanda BurtonAmanda Burton
10:54 16 Dec 22
Brilliant website and an excellent service. Nick provided not only detailed advice and supplier contacts, but highlighted the considerations of various products so I could make an informed choice. Our Sunvista minimal sliders were fitted this week and I couldn't be happier, stunning. Thanks once again for your advice and recommendations, invaluable!
Keith BarnesKeith Barnes
17:18 10 Dec 22
Very helpful advice given to my question, including the name of 3 different companies that i could try for the product being enquired about. Many thanks
Munim ChowdhuryMunim Chowdhury
11:45 13 Sep 22
Nick has been very helpful on signposting me to a number of partner organisations for steel/aluminium doors.
SUSAN wallaceSUSAN wallace
17:26 31 Aug 22
My experience with this firm was exceptionally good and this is notalways the case as a female, dipping a toe into technical waters.I was spoken too with courtesy and at a level that helped me consolidate what was needed .On top of that I was given a list of companies and places where I could obtain the type of product I needed.I could not thank them enough and would certainly go there again and reccommend others do too.
Paul SalterPaul Salter
22:39 22 Aug 22
Contacting Aluminium Trade Supply is like contacting the Oracle direct. Advice is always comprehensive and balanced. On multiple occasions they have provided me with options that fully meet our objectives. Many thanks.
Nick McCormackNick McCormack
20:25 14 Aug 22
Really helpful and useful came back to me on a Sunday with some invaluable information. Highly recommended.
ray addisonray addison
13:14 14 Aug 22
received a prompt reply to my query,and helpful information from ATS