Let’s face it - nobody wants to live in a stuffy, stale house. That’s where purge ventilation comes in. Whether you're dealing with smoky mishaps in the kitchen, humidity from a long shower, or just a hot summer day, fresh air is a must. Luckily, the UK Building Regulations Part F has your back.
If you’ve never heard of Part F, don’t worry. It’s the rulebook for how your home breathes, and purge ventilation is one of the important areas covered (specifically sections 1.26 to 1.31).
Traditionally, the advice has been simple: open your windows and doors! But let’s be honest - this doesn’t always work for everyone. Pollution, Noise, chilly air, and even security concerns make this old-school method less than ideal, especially in today’s modern, airtight homes. So what’s the better option?
Let’s dig in.
What Is Purge Ventilation Anyway?
Purge ventilation is the rapid removal of unwanted indoor air - paint fumes, burnt toast smoke, or extra humidity from cooking and bathing etc. It’s all about flushing out bad air and letting the good stuff in - fast.
Part F recommends large openings (like windows or doors) that provide at least 1/20th of the room's floor area in openable space, with direct access to the outdoors. But there’s a catch…
The Problem with “Just Open a Window”
Sure, it’s easy, but it’s not always practical. Here’s why opening up isn’t the ultimate fix:
Noise Pollution: If you live near traffic or in a busy area, you’re letting in a lot more than fresh air.
Outdoor Air Quality: Unfortunately, opening your windows can invite in vehicle exhaust emissions, pollen, and other nasties.
Heat Loss: Winter + open window = icy blast + higher heating bill.
Allergens: Pollen season? Hello sneezing fit!
Security Risks: Leaving a door or window open, especially on the ground floor, isn’t always the safest choice.
A Smarter Solution: Mechanical Ventilation
Thankfully, there’s a modern way to purge your home without cracking a single window. Enter: mechanical ventilation systems.
These systems do the heavy lifting for you, pulling out stale air and bringing in fresh, filtered air. Bonus: they’re quieter, more energy-efficient, and safer than the old open-window method. There are various systems available, and while all of them extract, not all of them have the option of supplying filtered fresh air back into a building. However, the key here is the removal of indoor air pollutants, and there will be a system that will work for you regardless of the limitations of your home for installation.
Here are some popular options:
1. MVHR & dMVHR (Mechanical Ventilation with Heat Recovery)
These are the superheroes of home ventilation. They extract old air and bring in new, filtered air, while capturing the heat from the outgoing air and using it to warm the incoming air. That means lower bills and cozy winters. Most MVHR systems even have a manual purge mode - just press a button and they ramp up airflow to quickly clear the air. Although MVHR systems are very intrusive when it comes to installation and are best installed during construction of new homes or major renovations, dMVHR systems are much simpler to install directly through external walls, similar to your standard bathroom fans, and are easy to retrofit to your existing building.
2. MEV & dMEV (Mechanical Extract Ventilation)
These systems extract stale air from wet rooms (like kitchens and bathrooms) and vent it outdoors. You’ll still need some way for fresh air to get in (like trickle vents), which won't be filtered, but these systems are a solid, low-cost solution and still control the airflow better than leaving doors and windows open.
3. High-Rate Extract Fans (Purge Fans)
Need to vent just one room in a hurry? High-powered extract fans are your friend. These are often activated by a switch or sensor and are perfect for bathrooms, kitchens, or utility rooms and can also be used to control other living spaces where puging could be a benefit, such as living rooms or conservatories.
Why Go Mechanical?
Let’s break it down:
✅ Less Noise
✅ Cleaner Air (thanks to filters!)
✅ Lower Heating Costs
✅ Fewer Allergens
✅ Better Security
In short: You get all the fresh air without the downsides of opening your home to the elements.
So, What Should You Choose?
Here’s a quick guide:
Best for new builds or major renovations: MVHR systems. They’re efficient, whole-home solutions - just know they’re easier to install during construction.
Best for existing homes: dMVHR units. These single-room options are great retrofits, and some models can work together wirelessly to create a whole-house ventilation system.
Budget-conscious options: MEV or dMEV systems. More affordable, less intrusive, but no air filtering, and you’ll rely on outdoor air via vents or gaps in the fabric of older buildings.
For specific room purging: High-powered purge fans. Great if you just want to target one area quickly.
Recommended Products
Here’s our tried-and-tested lineup:
🌀 MVHR
→ Want full-home coverage? Visit Clean Air Direct - Our new website that specialises in MVHR Specifications. We offer a free spec and design service to make sure it fits your space and meets every regulation.
🌀 dMVHR
→ Blauberg Vento-Maxi Single Room Heat Recovery Unit – These can be installed individually or in multiple rooms, working together wirelessly for whole-house coverage.
🌀 MEV
→ Vent Axia 443298 MVDC-MSH – Smart humidistat control + manual purge switch option. Customisable extraction speeds for every situation.
🌀 dMEV
→ Silent Tornado ST100DMEVS – Quiet background extraction with manual boost. Full control, no auto-boosting via humidity means you control when the unit boosts, making it ideal for quiet trickle installations in bedrooms and other living areas like conservatories!
🌀 High-Rate Extract Fan
→ Tornado TT150PROS – A solid inline fan that gets the job done. Perfect for targeted purge in one room.
Final Thoughts
Purge ventilation isn’t just a regulatory checkbox, it’s a real game-changer for air quality, energy savings, and home comfort. And while traditional window-opening methods still work, mechanical solutions are the way forward if you want consistent, clean, and efficient airflow, without compromising your comfort, security, or style.
It's important to note that installing central purge ventilation doesn't mean that bathroom, kitchen and utility room fans can be ignored, these still need to be present to meet building regs, but these can be incorporated as part of a whole house system such as MVHR or MEV systems where extract points can be included in these areas. For MEV systems, you can also include a central extraction point in the home to help with purging and with MVHR systems, supply points installed in living spaces and hallways/landings will help with the through-flow of air in the home when purging.
Whether you're building from scratch or upgrading your current setup, there's a smart system out there to help your home breathe easy. Ready to make the switch? We’re here to help every step of the way.