MVHR Explained: Your Mechanical Ventilation with Heat Recovery Questions Answered

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MVHR Explained: Your Mechanical Ventilation with Heat Recovery Questions Answered

Are you curious about the inner workings of MVHR? This innovative system, short for Mechanical Ventilation with Heat Recovery, revolutionises the way we ventilate and heat our buildings. Say goodbye to stale air and hello to fresh, filtered air while simultaneously reducing your carbon footprint.

In this blog post, we delve into the world of MVHR and uncover how this ingenious technology works its magic.

An Overview of MVHR

What does MVHR mean?

MVHR, an acronym for Mechanical Ventilation with Heat Recovery, is a clever system designed to circulate fresh air while conserving warmth. The “Mechanical Ventilation” part refers to the method of using mechanical devices to move air, and “Heat Recovery” denotes the process of capturing and reusing heat that would otherwise be lost.

Where is MVHR most commonly used?

MVHR systems are typically installed in residential and commercial buildings that require efficient ventilation and temperature control. They find their place in houses, apartments, offices, schools, and other spaces where a comfortable and healthy indoor environment is essential.

What is MVHR used for?

MVHR is used to provide fresh air and remove stale air in buildings, ensuring a healthy and comfortable indoor environment. It also helps reduce energy consumption by recovering and reusing heat.

How does MVHR work?

MVHR works by using fans to bring fresh air into a building while simultaneously extracting stale air. The clever part is the “Heat Recovery” aspect. The system has a special component called a heat exchanger that transfers heat from the outgoing air to the incoming air, without mixing them. This way, the fresh air gets warmed up in the winter and cooled down in the summer, making it more comfortable inside. The heat recovery process also saves energy by reducing the need for additional heating or cooling.

What components are involved in MVHR?

MVHR systems consist of several key components that work together to provide efficient ventilation and heat recovery:

  • Supply Air Unit: Draws fresh air from outside, filters it, and prepares it for distribution.
  • Extract Air Unit: Removes stale air from the building.
  • Heat Exchanger: Transfers heat from the extracted air to the incoming fresh air.
  • Ductwork: Distributes the fresh air throughout the building and extracts the stale air.
  • Controls and Sensors: Monitor and regulate air quality, humidity, and temperature for optimal performance.

A Diagram showing how MVHR works

The Expenses of MVHR

How much does an MVHR unit cost?

The cost of an average MVHR unit can vary, but it typically ranges from £1,000 to £3,000 or more. The price depends on the specific features, capacity, and brand.

How does MVHR reduce energy bills?

MVHR systems help reduce utility bills by recovering and reusing heat from the outgoing air, which would otherwise be wasted. By transferring this heat to the incoming fresh air, less energy is required for heating or cooling, resulting in significant energy savings.

Is MVHR expensive to run?

The running costs of MVHR systems can vary depending on factors such as the size of the building and the specific model chosen. Generally, the energy savings achieved by these systems outweigh the operational expenses. As an example, a typical MVHR system with good energy recovery can cost around £40 to £80 per year to operate. However, these systems can significantly reduce energy bills by up to 40% or more, resulting in substantial long-term savings. It’s important to consider these figures alongside the initial investment when evaluating the cost-effectiveness of installing an MVHR system.

What are the running costs of MVHR throughout the year?

The cost of running MVHR can vary throughout the year. During colder months, when more heating is required, MVHR may lead to higher energy bills. However, in warmer months, when less heating is needed, the energy savings from heat recovery can offset the running costs, potentially resulting in overall cost savings.

What work is involved when installing an MVHR system?

Installing an MVHR system typically requires professional expertise and involves various tasks, including ductwork installation, electrical connections, and positioning the supply and extract units. Depending on the complexity and size of the installation, it may involve some disruption and modifications to the building. Professional installers ensure that the system is correctly set up and integrated into the existing infrastructure for optimal performance.

Do you need radiators with MVHR?

Yes, radiators or other heating systems are typically needed in conjunction with MVHR to provide heat distribution throughout the building.

The Pros and Cons of MVHR

What are the benefits of MVHR?

MVHR offers several benefits for buildings and occupants alike. It ensures a constant supply of fresh, filtered air, promoting healthier indoor environments. By recovering and reusing heat, it reduces energy consumption and lowers utility bills. Additionally, MVHR helps maintain comfortable temperatures, reduces the risk of condensation and mold, and can contribute to a quieter living or working space.

What are the negatives of MVHR?

While MVHR systems offer numerous benefits, there are a few potential drawbacks to consider. Installation and maintenance costs can be higher compared to traditional ventilation systems. Additionally, improper installation or inadequate maintenance may lead to reduced efficiency or even the risk of indoor air quality issues.

What are the health benefits of MVHR?

MVHR systems provide significant health benefits by supplying fresh, clean air while removing airborne contaminants. The systems are equipped with filters that effectively capture particles, dust, pollen, and other pollutants from the incoming air. Filtering the air improves indoor air quality which helps reduce the risk of respiratory problems, allergies, and other health issues.

Will MVHR help with allergies?

Yes, MVHR systems can be beneficial for allergy sufferers. By filtering and removing airborne allergens, such as pollen and dust particles, MVHR helps improve indoor air quality and reduces the presence of allergens, thus alleviating allergy symptoms.

MVHR in Different Seasons

Does MVHR work in winter?

Yes, MVHR works in the winter. It helps maintain a comfortable indoor temperature by recovering and reusing heat from the outgoing air, reducing the need for additional heating.

Does MVHR work in summer?

Yes, an MVHR system works in summer by providing ventilation while recovering and reusing the coolness of the incoming air.

Should I turn off MVHR in Summer?

It is generally not recommended to turn off MVHR in the summer. MVHR helps remove excess heat and maintains a balanced airflow, contributing to a comfortable indoor environment.

How does MVHR work in winter?

During winter, MVHR systems extract warm, stale air from inside, recover the heat, and use it to warm the fresh incoming air, ensuring a continuous supply of fresh, preheated air.

How does MVHR work in summer?

During summer, MVHR systems extract warm indoor air, recover its coolness, and supply fresh, pre-cooled air, maintaining a comfortable indoor environment.

Will an MVHR system heat my house during the winter?

While MVHR systems can help distribute and recover heat, they are not designed to be the primary heating source for a house in winter. MVHR systems primarily focus on providing ventilation and maintaining indoor air quality. They work in conjunction with a heating system to circulate and distribute heat throughout the house.

Will an MVHR system cool my house during the summer?

MVHR systems do not have a specific cooling function and are not designed to actively cool a house during the summer. However, by providing fresh air and maintaining a balanced airflow, MVHR systems can contribute to a more comfortable indoor environment in conjunction with other cooling methods, such as air conditioning or natural ventilation.

Should I turn my MVHR system off at night?

It is generally recommended to run an MVHR system continuously, including at night, to maintain good indoor air quality and ventilation.

MVHR Filter Questions

What are MVHR filters?

MVHR filters are essential components that capture and remove particles and pollutants from the incoming air. Typically, these filters are flat panels made from a synthetic non-woven fibre. They are designed to trap dust, pollen, pet dander, and other airborne contaminants, helping to improve indoor air quality.

Can you wash MVHR filters?

MVHR filters are generally not washable as they are designed for single-use. They should be replaced according to the manufacturer’s guidelines to ensure optimum filtration efficiency.

How often should I replace MVHR filters?

The frequency of MVHR filter replacement can vary depending on factors such as the specific system, air quality, and usage. Generally, it is recommended to replace MVHR filters every 6 to 12 months to ensure optimal performance and maintain good indoor air quality. Regular inspections and following manufacturer guidelines are important for determining the appropriate filter replacement schedule.

How do you replace MVHR filters?

To replace MVHR filters, follow the manufacturer’s instructions. Typically, this involves accessing the filter compartment, removing the old filter, and inserting a new one securely.

Does filter grade affect MVHR performance?

Yes, the filter grade used in MVHR systems, such as G3, G4, or M5, directly impacts their performance. Lower-grade filters like G3 offer basic particle filtration, while higher-grade filters like G4 and M5 provide improved filtration efficiency, capturing finer particles and pollutants. Choosing a higher-grade filter enhances the air quality and ensures better protection against allergens and contaminants.

G3, G4 and M5 Replacement Filter Grade Guide

General MVHR Questions

Is MVHR worth getting?

Deciding whether to install MVHR depends on various factors. The pros include improved indoor air quality, energy efficiency and reduced energy bills. However, costs, including installation and maintenance, can vary significantly for each project. There are numerous types and models of MVHR systems, making it crucial to select the right one for your installation. It’s essential to assess individual needs and consult with professionals to determine if the benefits outweigh the investment.

Is MVHR air conditioning?

No, MVHR is not air conditioning. While MVHR helps maintain indoor air quality and regulates temperature, it is a separate system from air conditioning, which focuses on cooling and dehumidifying the air.

Are MVHR systems noisy?

MVHR systems are generally designed to operate quietly, with noise levels ranging from 20 to 50 decibels (dB). For comparison, a quiet library is around 30 dB, while normal conversation reaches about 60 dB. MVHR units emit low noise levels, with some modern models operating as low as 20 dB, which is almost equivalent to a whisper. Proper installation and regular maintenance contribute to maintaining the system’s quiet operation, ensuring a peaceful indoor environment.

What is the life expectancy of an MVHR unit?

The life expectancy of an MVHR unit can vary depending on factors such as usage, maintenance, and quality. On average, a well-maintained MVHR system can last between 15 to 20 years or more.

Does MVHR remove smells?

Yes, MVHR systems can help remove odours and smells by continuously extracting and filtering the air, reducing unwanted odours in the indoor environment.

Does a house need to be airtight for MVHR?

While it is not necessary for a house to be completely airtight, a reasonably airtight building helps maximise the efficiency of an MVHR system.

What is an alternative to MVHR?

Some of the alternatives to MVHR are: Natural Ventilation, Exhaust Fans, or Decentralised Ventilation Units. These alternatives may have lower upfront and installation costs but could have higher running costs and may provide less energy efficiency compared to MVHR systems. The choice depends on individual needs, budget, and the specific requirements of the building.

For more information, advice or to place an order contact us today by email or phone.

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