When it comes to improving your home, ventilation is one of the most overlooked elements. People often ask: “Can I put MVHR into my renovation or refit?” The short answer? Yes... 100% yes.
But before you rush to install a unit, there are a few important things to understand about how MVHR works, why airtightness is essential, and why extraction systems in most homes are simply not up to the job.
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Renovations vs. Simple Redecoration
If you’re carrying out a full renovation — stripping the property back to the walls, starting fresh, and making the house airtight — then MVHR (Mechanical Ventilation with Heat Recovery) is a fantastic addition.
But if your “renovation” just means a lick of paint and some decorating, then no, MVHR isn’t for you. For the system to work, your home needs to be airtight. Without that, air will leak everywhere, and the system becomes pointless.
Think of MVHR as your home’s lungs: it balances airflow, brings in fresh filtered air, and removes stale air — without you needing to fling windows wide open in the middle of winter.
Where Can MVHR Units Go?
MVHR units aren’t as difficult to integrate as many think. They can be:
- In a loft (with proper insulation as per manufacturer’s instructions).
- In a garage.
- In a cupboard — about the size of a washing machine.
- Boxed into walls with ducting routes tailored to your property.
The golden rule: always follow manufacturer’s instructions. They override everything else.
Why Extraction is Usually Wrong
Walk into most homes (or even commercial spaces), and you’ll find a tiny, wall-mounted bathroom fan that’s supposed to “do the job.” The truth? They’re useless.
Extraction isn’t guesswork. Every occupied room has an air change rate — the number of times per hour the air needs to be completely replaced. Bathrooms, kitchens, and WCs all have specific requirements.
If the fan isn’t powerful enough, or the door has no gap at the bottom, you’ll end up with negative pressure: the fan stalls, the room never clears, and you’re left with condensation, mold, and frustration.
Tip: Always leave at least 25mm under bathroom doors so the fan can “feed.” Without an inlet, extraction fails.
Kitchen Extraction — A Common Problem
If you’ve ever cooked a steak and set off the smoke alarm while throwing open all the windows, it’s a sure sign your kitchen extraction isn’t up to scratch.
Signs your system is underperforming:
- Grease on top of cupboards — especially if you’re using a recirculating hood.
- Lingering smells after cooking.
- Overheating when cooking large meals.
A properly sized extraction system should remove heat, grease, and contaminants efficiently, without dumping everything back into your kitchen.
Why Good Extraction Protects Your Health (and Your Wallet)
Condensation and mold aren’t just annoying — they’re unhealthy. Black mold spores are linked to respiratory problems, allergies, and long-term health issues. If you’re constantly battling mold in your bathroom, the culprit could be poor extraction.
And then there’s wasted energy. Many people “crack the window” after a shower. All that valuable heat just escapes. With MVHR, that warmth can be recovered and redistributed around your home, keeping you comfortable while cutting bills.
The Bottom Line
- Yes, you can fit MVHR into a renovation — provided it’s a proper strip-back job with airtightness in mind.
- Extraction must be correctly sized — not just a cheap fan in the wall.
- Bathrooms, kitchens, and WCs all need adequate ventilation to prevent condensation, mold, and lingering smells.
- MVHR saves energy and improves health by recycling heat and keeping air fresh.
If you’re renovating, extending, or simply fed up with condensation and poor air quality in your home, it’s worth speaking to a ventilation specialist. Done properly, MVHR and well-sized extraction will transform the comfort, health, and efficiency of your property.