Centralised Heat Recovery

Everything You Need to Know About Heat Recovery Ventilation (MVHR)

If you’re looking for a way to improve air quality, lower your energy bills, and ensure your home complies with building regulations, a Mechanical Ventilation with Heat Recovery (MVHR) system could be the perfect solution.

This guide explains how MVHR systems work, the benefits they offer, and how they help meet UK building standards. We’ve also included answers to common questions and a jargon buster to make everything as clear as possible.

What is an MVHR System?

An MVHR system continuously extracts stale air from your home or office and replaces it with fresh, filtered air from outside. What makes MVHR unique is its ability to recover up to 95% of the heat from the outgoing air, transferring it to the incoming air. This process keeps your home warm without wasting energy.

MVHR systems are perfect for homes that are well-insulated and airtight. Whether you're building a new house or upgrading an older property, MVHR offers a range of benefits from better air quality to lower energy consumption.

How Does an MVHR System Work?

Here’s a step-by-step look at how an MVHR system works:

1. Extract Stale Air: The system extracts stale, humid air from rooms such as kitchens, bathrooms, and utility rooms. This air is full of moisture and pollutants.
2. Heat Recovery: As the stale air leaves the building, it passes through a heat exchanger. This clever device captures the heat from the outgoing air and uses it to warm the fresh air coming in, without the two air streams mixing.
3. Fresh Air Supply: Fresh air is drawn in from outside, filtered to remove dust, pollen, and other particles, and warmed by the recovered heat before it’s circulated throughout the house.
4. Balanced Ventilation: This constant flow of fresh, warmed air is supplied to your living areas, ensuring the air quality is good without any heat being wasted.
5. Bypass Mode (Summer Use): In warmer months, MVHR systems can bypass the heat recovery process, allowing cooler outdoor air to flow inside, keeping your home comfortable without overheating.

Benefits of an MVHR System

1. Energy Savings

MVHR systems capture heat that would normally be lost through conventional ventilation, reducing the need to use extra heating. This makes your home more energy-efficient, helping you save on energy bills and lower your carbon footprint.

2. Better Air Quality

With modern homes being more airtight, pollutants and moisture can build up indoors. MVHR systems continually replace stale air with fresh, filtered air, reducing the risk of allergies, asthma, and mould growth.

3. Filtration for Healthier Air

MVHR systems come with F7 filters as standard, which are highly effective at removing fine dust and pollen from the air, making your home a healthier environment.

For those with allergies or sensitivities to pollutants, H13 HEPA filters can be added to filter out even finer particles, such as allergens and harmful pollutants.

Additionally, carbon filters can be included to neutralise odours and remove volatile organic compounds (VOCs), improving air quality and eliminating smells.

4. Consistent Comfort

MVHR systems help maintain a steady 21°C temperature throughout the year by recovering heat from the outgoing air. This not only reduces the need for additional heating but also takes the load off your existing heating system, making it work more efficiently. With balanced ventilation, your home stays warm in the winter and comfortably cool in the summer.

5. Quiet Operation

Modern MVHR systems are designed to operate quietly, making them perfect for bedrooms, living areas, and offices. Proper installation ensures noise levels are kept to a minimum.

What About Building Regulations?

When installing an MVHR system, it’s important to ensure it complies with UK Building Regulations. These rules are in place to make sure your home is safe, efficient, and comfortable. The key regulations relevant to MVHR systems are:

Part F: Ventilation & MVHR

Part F ensures that homes and buildings have proper ventilation to maintain indoor air quality.

How MVHR Helps: MVHR systems meet Part F requirements by continuously ventilating your home, ensuring stale air is removed and fresh air is supplied, without wasting heat.

Part L: Conservation of Fuel and Power & MVHR

Part L focuses on improving energy efficiency in buildings to reduce fuel consumption and carbon emissions.

How MVHR Helps: By recovering up to 95% of the heat from outgoing air, MVHR systems help buildings meet Part L requirements, reducing the need for additional heating and conserving energy.

Part O: Overheating & MVHR

Part O aims to minimise the risk of homes overheating, especially during the summer months.

How MVHR Helps: MVHR systems can switch to a bypass mode in hot weather, circulating cool outdoor air into your home without adding unnecessary heat, helping to meet Part O requirements.

Why Compliance Matters

Making sure your MVHR system complies with Parts F, L, and O of the Building Regulations is essential. Non-compliance can lead to costly delays, fines, or retrofits. A properly installed MVHR system ensures you stay within regulations, while also enjoying better air quality, reduced energy bills, and a more comfortable home.

Frequently Asked Questions

1. How does an MVHR system work?

An MVHR system extracts stale air from your home, replaces it with fresh air, and recovers up to 95% of the heat from the outgoing air. This ensures continuous ventilation while maintaining indoor warmth.

2. Can I retrofit an MVHR system in an existing home?

Yes, MVHR systems can be retrofitted into older homes, although the process might be more complex due to existing ductwork and insulation. Proper planning and installation are key to ensuring the system works efficiently.

3. What’s the difference between MVHR and HRV?

MVHR (Mechanical Ventilation with Heat Recovery) and HRV (Heat Recovery Ventilation) are similar, but MVHR systems allow for better control over airflow and temperature, making them more efficient in airtight homes.

4. How much will I save with an MVHR system?

MVHR systems can reduce your heating bills by up to 30%, depending on your home’s insulation and size. Over time, the savings can be significant, particularly in homes with high energy demands.

5. Can MVHR systems work in all homes?

MVHR is most effective in airtight, well-insulated homes. In older, draughty properties, the benefits might be less noticeable unless the building has undergone insulation improvements.

6. Do MVHR systems help in summer?

Yes, many MVHR systems come with a summer bypass mode, which prevents the heat recovery process during warmer months, allowing fresh, cooler air to circulate without heating it.

7. Are MVHR systems noisy?

Modern MVHR systems are designed to be quiet. Proper installation and insulation of ductwork will ensure the system operates without disturbing noise, making it suitable for bedrooms and living spaces.

8. How often should I maintain the MVHR filters?

MVHR filters should be cleaned or replaced every 3 to 6 months, depending on usage and the air quality in your area. Upgrading to H13 or carbon filters may require more frequent maintenance to ensure they continue to work effectively.

9. Does an MVHR system help prevent condensation and mould?

Yes, MVHR systems are excellent at reducing indoor humidity by constantly removing moisture from the air. This helps to prevent condensation on windows and walls, which in turn reduces the risk of mould and mildew.

10. Will an MVHR system improve my EPC rating?

Yes, installing an MVHR system can improve your Energy Performance Certificate (EPC) rating. By enhancing energy efficiency, reducing heating demand, and improving air quality, MVHR systems contribute positively to your home’s EPC score.

11. Can I install an MVHR system myself?

It’s not recommended to install an MVHR system yourself. Professional installation ensures the system is correctly set up, complies with building regulations, and operates efficiently and quietly.

Jargon Buster

1. Heat Exchanger: The part of the MVHR system that transfers heat from outgoing stale air to incoming fresh air.
2. F7 Filter: A high-efficiency filter that captures fine dust and pollen, improving air quality and helping to reduce allergies.
3. H13 HEPA Filter: A high-performance filter that removes smaller particles, including allergens and pollutants, ideal for those with respiratory issues.
4. Carbon Filter: A type of filter that neutralises odours and removes volatile organic compounds (VOCs), making indoor air cleaner and fresher.
5. Bypass Mode: A function that allows fresh air to bypass the heat exchanger in summer, helping cool the house without adding heat.
6. Air Tightness: How well a building prevents air from leaking in or out. High airtightness is essential for MVHR to work effectively.
7. Ductwork: The pipes and channels that transport air around your home in an MVHR system.
8. Part F: The section of UK Building Regulations focused on proper ventilation.
9. Part L: The section of UK Building Regulations aimed at improving energy efficiency.
10. Part O: The section of UK Building Regulations designed to reduce the risk of overheating in buildings.
11. EPC: Energy Performance Certificate, a rating that measures how energy-efficient your home is.

Need More Help?

If you have more questions or want advice on choosing the right MVHR system for your home, we’re here to help. Contact us today to learn more about installation, maintenance, and finding the best system to suit your needs.

Investing in a Mechanical Ventilation with Heat Recovery (MVHR) system is not only a step towards improving your home’s air quality but also a smart way to reduce energy consumption and ensure compliance with modern building regulations. By maintaining a comfortable temperature year-round, filtering out pollutants, and enhancing energy efficiency, an MVHR system offers lasting benefits for both your home and your wellbeing.

Whether you're building a new property or upgrading an existing one, an MVHR system provides a reliable, sustainable solution to balance ventilation needs and energy conservation.

Ready to take the next step? Our team is here to help you make the right choice, from selecting the perfect MVHR system to professional installation and ongoing maintenance.

Contact us today for expert advice and start experiencing the many advantages of a heat recovery ventilation system in your home.