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Frequently Asked Questions About MVHR Systems

17 December 2024 | HRV

What is Heat Recovery Ventilation?

Heat Recovery Ventilation is a system that continuously supplies fresh, filtered air to your home while extracting stale air. What sets it apart from traditional ventilation systems is its ability to recover heat from the outgoing extract air before it leaves the building.  

This heat is recovered via a heat exchanger which then transfers it to the new incoming supply air. This helps temper the air, contributing to the overall heating of the space (saving up to £300 annually in a modern 2 bedroom apartment). This process ensures that your home remains well-ventilated and warm without wasting energy. By combining effective ventilation with heat recovery, these systems create a healthier and more efficient indoor environment.

Does a Heat Recovery System Save Money?

Yes it's true! A heat recovery system can save you money. By recovering and reusing heat that would otherwise escape through traditional ventilation, MVHR systems allows you to have your central heating set 1 to 2 degrees less!

This energy-saving feature is particularly beneficial in well-insulated, airtight homes where maintaining indoor temperature is a priority. While the initial installation cost may seem high, the reduction in energy bills often offsets this expense over time, making MVHR a cost-effective investment. It's estimated that a small 1/2 bed new build apartment takes £300 less to heat per year when a MVHR system is installed.  

How Much Does an MVHR System Cost to Install?

The cost of installing an MVHR system varies depending on the size of your home and the complexity of the installation. Enhanced energy efficiency improves indoor air quality, and reduced heating costs all contribute to the overall value of the system.  If you are considering an installation The Air Shop, our sister company, offer a quick 60 MVHR System Quote

How do I Maintain My MVHR System?

Proper maintenance is key to ensuring your MVHR system operates effectively and lasts for years. Regularly checking and replacing filters is one of the most important steps, as clean filters are essential for optimal airflow and air quality. We recommend replacing filters every three to six months and scheduling professional servicing annually to help identify/address potential issues before they escalate.

What Are the Key MVHR Design Considerations?

Sizing the Unit Correctly Never undersize the unit! It will have to work harder to do its job, which means increased noise. An MVHR system operates at a constant trickle speed (calculated by floor area, number of bedrooms, and occupancy), and we would never recommend setting it above 70% of the MVHR unit’s airflow capacity. Ducting also needs to be considered, as it causes resistance within the duct, which has a significant impact on overall performance.

Location of the Unit We recommend placing the unit in a central location, such as a hall or utility cupboard, to reduce noise disturbance as much as possible. MVHR units are not designed to be noisy, but you want to minimise any potential issues (poor installation is the main cause of noise). MVHR is not a 'fit and forget' system! They require annual maintenance, so the unit should be located somewhere easily accessible.

Ducting Type An MVHR system is made up of both the unit AND the ducting. Both parts play an equal role in delivering effective ventilation to the home. Do not use flexible ducting! (It is only recommended to use this directly from the unit when necessary due to positioning.) Also, it’s important to use insulated ducting to prevent water vapour from collecting and sitting in the ducts over time.

Is MVHR Suitable for My Home?

MVHR is most commonly used in new-build homes; however, it can also be applied to existing homes and extensions. It is a highly effective ventilation system, especially if your property has been designed or renovated to "keep the heat in." MVHR works on the principle of recovering and reusing heat that would otherwise be lost. If your home is not airtight or well-insulated, this heat will escape through the building's facade, reducing heat recovery efficiency.

How Often Do I Need to Change the Heat Recovery System Filters?

Depending on your location, the filters usually need to be cleaned or changed every 6 months. Our service includes new filters (Basic Barrier G3), but these can be upgraded.

The Basic Barrier Your essential, entry-level MVHR heat recovery filter to aid indoor air quality and protect your unit and motors. It filters out coarse, visible particles such as dust, sand, hair, insects, and other organic materials.

The Dust Destroyer Our dust destroyer has improved filter density and coverage. If you are sensitive to house dust, dust mites, or allergies linked to these particles, this upgrade is ideal.

The Summer Sneezer A higher-grade filter for common summer allergies. If summer brings nose blowing and itchy eyes, the Summer Sneezer is the best upgrade for you.

The Proper Stopper This is the highest-grade filtration option for your MVHR heat recovery system. It is ideal for high-pollution areas with traffic particulate concerns and for those with high sensitivity to airborne particles. It’s also the perfect option for anyone concerned about their indoor air quality. This option provides complete filtration and is typically added within the ducting network. It filters out very fine dust, combustion particles, bacteria, viruses, and smaller spores

If you have questions about a MVHR system for your home, or one that you alrady have installed we are here to help.  Call on 033 0223 4180 or email enquires@hrv-group.com

Our sister company The Air Shop also have lots of useful resources about MVHR systems that might be of interest.

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