Key Takeaways
- MVHR systems recover up to 93% of heat from outgoing stale air, significantly reducing heating costs
- Single room units suit apartments and retrofits; whole house systems are ideal for new builds and larger homes
- Building Regulations Part F requires mechanical ventilation in new builds — MVHR satisfies this while also meeting energy efficiency requirements
- Correct sizing matters — match the unit's airflow rate (m³/h) to your property's floor area and number of rooms
- With filter changes every 6–12 months, a well-maintained MVHR system will last 25–30 years
A heat recovery system — or MVHR (Mechanical Ventilation with Heat Recovery) — is one of the most effective ways to keep a home well-ventilated, free from condensation, and energy-efficient. But with different system types, sizes, and brands to navigate, knowing where to start isn't always straightforward. This guide covers everything you need to make the right choice.
What Is a Heat Recovery System?
An MVHR system provides your home with a continuous supply of fresh, filtered air while recovering the heat from the stale air it extracts — heat that would otherwise be lost to the outside. Modern MVHR units recover between 78% and 93% of that heat, meaning the incoming fresh air arrives at close to room temperature even in winter.
The two airstreams — outgoing stale air and incoming fresh air — never mix inside the unit. They pass on either side of a heat exchanger, with warmth transferring from one to the other. The result is consistent ventilation without draughts, without heat loss, and without the need to open windows.
What Are the Benefits of an MVHR System?
Reduced Heating Bills
By recapturing heat that would otherwise be exhausted outside, MVHR reduces the demand on your boiler or heat pump. The higher the heat recovery efficiency of the unit, the greater the saving — units like the Zehnder ComfoAir range achieve up to 93% recovery, making a measurable difference to annual energy bills.
Eliminates Condensation and Mould
MVHR continuously extracts humid air from kitchens and bathrooms, preventing moisture from settling on cold surfaces. For new builds in particular — which are highly airtight — MVHR is the most effective way to control humidity and stop mould taking hold.
Improved Indoor Air Quality
All incoming air passes through filters before entering the living spaces, removing dust, pollen, and airborne pollutants. This is particularly beneficial for households with allergy sufferers or anyone with a respiratory condition such as asthma.
Building Regulations Compliance
Under UK Building Regulations Part F, all new residential builds must meet minimum ventilation standards. MVHR is the go-to solution for new builds and major renovations — it satisfies Part F and contributes towards Part L (energy efficiency) compliance simultaneously. For Passivhaus-standard builds, MVHR is effectively essential.
Single Room Heat Recovery vs Whole House MVHR
Not every property needs a full whole-house system. Understanding the difference helps you choose the right solution for your situation.
Single Room Heat Recovery Units
Single room units are wall-mounted and handle ventilation for one space only — typically installed through an external wall. They're well suited to:
- Apartments where a whole-house system isn't feasible
- Individual rooms with persistent condensation or poor air quality
- Retrofits where full ductwork installation isn't practical
- Budgets that can't stretch to a full system
Entry-level single room units start from around £300–£500.
Whole House MVHR Systems
A whole-house system uses a central unit — typically installed in a loft or utility cupboard — connected to ducting that runs to every room. Stale air is extracted from wet rooms (kitchen, bathrooms, utility), and fresh air is supplied to living rooms and bedrooms.
Whole-house systems are the right choice for:
- New builds and major renovations
- Larger homes (3+ bedrooms) where room-by-room solutions would be impractical
- Properties built to high airtightness standards
- Anyone prioritising maximum energy efficiency
Browse our full range of whole house MVHR units, including models from Vent-Axia, Zehnder, S&P, and Elta.
How to Size an MVHR System
Correct sizing is critical — an undersized unit won't ventilate the property effectively, while an oversized one costs more to run than necessary. Sizing is based on floor area and number of rooms:
- 2–3 bedroom house (up to ~120 m²): 200–280 m³/h
- 4 bedroom house (~120–200 m²): 280–400 m³/h
- Large 5+ bedroom house (200 m²+): 400 m³/h and above
If you're unsure which unit is right for your property, get in touch at hello@efans.co.uk and we'll help you size correctly before you order.
Which MVHR Brand Should I Choose?
Vent-Axia
Vent-Axia is the most widely specified MVHR brand in UK residential new builds. Their Sentinel Kinetic range covers airflow rates from 117 m³/h up to 684 m³/h, with heat recovery efficiencies between 81% and 93%. Well-supported, competitively priced, and available in left and right-hand configurations. A good all-round choice for most domestic installations.
Zehnder
Zehnder's ComfoAir range sits at the premium end of the market. Recovery efficiencies up to 93%, ultra-quiet operation, and app-based control make these units the preferred choice for Passivhaus projects and specifiers where performance and noise levels are the priority. The ComfoAir Q series offers app control and airflow rates from 350 m³/h to 600 m³/h.
S&P and Elta
S&P and Elta offer well-priced MEV (Mechanical Extract Ventilation) and entry-level MVHR units suited to smaller properties and retrofit installations where a full whole-house system isn't required.
MVHR vs MEV — What's the Difference?
MEV (Mechanical Extract Ventilation) only extracts air from the property — it doesn't supply fresh air or recover heat. It's a simpler, lower-cost system suited to existing homes with some natural air infiltration. MVHR both extracts and supplies, recovering heat in the process — making it significantly more energy-efficient but also more complex and expensive to install.
For new builds and well-sealed properties, MVHR is the correct choice. For older homes with naturally draughty construction, MEV may be sufficient.
How Much Does an MVHR System Cost?
The unit cost alone ranges from around £300 for a single room system up to £3,000+ for a premium whole-house unit. A full whole-house installation — including ductwork, fittings, commissioning, and labour — typically costs between £2,500 and £6,000 depending on property size and complexity. The investment pays back through reduced heating bills and a more comfortable, healthier home environment.
MVHR Maintenance
MVHR systems require minimal ongoing maintenance but it must be done regularly to keep the system running efficiently:
- Filter replacement: Every 6–12 months, depending on air quality and usage. Most units have easily accessible filter panels.
- Annual check: Inspect ducting for blockages and check airflow rates are balanced.
- Heat exchanger clean: Every 2–3 years, or as recommended by the manufacturer.
A well-maintained MVHR system will last 25–30 years. Neglected filters are the most common cause of reduced performance and premature failure.
Frequently Asked Questions
What is the difference between MVHR and a standard extractor fan?
A standard bathroom extractor fan simply removes stale air — all the heat in that air is lost to the outside. An MVHR unit recovers that heat via a heat exchanger and uses it to warm incoming fresh air, making it far more energy-efficient. MVHR also supplies filtered fresh air to every room, whereas a standard extractor fan only serves the room it's installed in.
Does MVHR replace the need for a boiler?
No — MVHR reduces heat loss from ventilation but doesn't generate heat. It works alongside your existing heating system, reducing how hard it needs to work. Some whole-house systems can integrate with heat pumps as part of a broader low-carbon heating strategy.
Can MVHR be retrofitted to an existing home?
Yes, but it's significantly more involved than a new-build installation. Ducting needs to be routed through the property, which can be disruptive and costly in an existing home. For retrofits, single room heat recovery units are often the more practical choice — they require only a single hole through the external wall per room.
How noisy is an MVHR system?
A correctly specified and installed whole-house MVHR system should be virtually silent in the living spaces. The unit itself is typically installed in the loft or a plant room, and the air supply to rooms arrives at low velocity through diffusers. Zehnder ComfoAir units in particular are noted for ultra-quiet operation. If noise is a concern, look for units with low dB(A) ratings and ensure the installer correctly sizes the ductwork.
Is an MVHR system worth it?
For a new build or a well-sealed home, yes — MVHR is one of the most cost-effective ways to meet ventilation requirements while minimising heat loss. For older, draughtier properties, the payback period is longer and MEV or targeted extractor fans may offer better value. If you're unsure which approach is right for your property, get in touch and we'll advise.
How often do MVHR filters need replacing?
Most manufacturers recommend replacing filters every 6–12 months. Running a unit with blocked or saturated filters reduces airflow, drops heat recovery efficiency, and puts unnecessary strain on the motor. Replacement filters are available for all units we stock.
Ready to choose? Browse our full range of whole house heat recovery units — or contact us at hello@efans.co.uk for sizing advice.
Need Further Help?
If you need additional assistance or have questions about choosing the right heat recovery system for you project, feel free to reach out to us at hello@efans.co.uk.