Residential ventilation: Price vs performance
Mechanical ventilation systems can be key to providing good indoor air quality (IAQ). However, when the installation price takes prominence over performance and energy efficiency, IAQ can be compromised. Not only that, but products that consume more energy will result in far higher bills and a higher carbon footprint over the lifetime of the product.
Correct product selection is vital in protecting the health of occupants and the integrity of the building structure. This article explores the different types of residential ventilation systems, the impact of poor product selection, the reasons why systems underperform, and how to identify high performing products.
Residential ventilation systems overview
Decision makers can choose from a wide range of residential ventilation systems. Main options include:
Mechanical Extract Ventilation (MEV) - Centralised or Decentralised
These systems continuously extract stale air from wet rooms (kitchens, bathrooms, WCs). While fresh air enters through trickle vents in windows or walls.
Systems can be centralised (one unit serving multiple rooms) or decentralised (individual extract fans per room). While they are simple, cost effective, low energy systems which prevent condensation and mould, they do not include heat recovery, and rely on natural infiltration for fresh air.
Mechanical Ventilation with Heat Recovery (MVHR)
These systems extract stale air and simultaneously supply fresh, filtered air. A heat exchanger transfers heat from the outgoing air to the incoming air, reducing heat loss.
These systems save energy by reducing heating demand. They greatly improve IAQ as they filter the incoming air, removing pollutants and allergens, and provide a consistent airflow, along with humidity control. However, they have a higher upfront cost and require more regular maintenance, including regular filter changes.
Positive Input Ventilation (PIV)
This system comprises of a single unit (typically in the loft or hallway) which gently pushes fresh, filtered air into the home. It creates positive pressure, forcing stale, humid air out through natural leaks and trickle vents.
While it has a low installation cost, is low maintenance and helps control condensation and damp, it does not include heat recovery and relies on the home’s airtightness and natural ventilation for effectiveness.
Each home is different, with aspects such as size, layout, number of wet rooms, climate, occupancy and IAQ requirements affecting the ventilation system specified. With so many variables to consider, there is no ‘one size fits all’ approach.
The impact of poor product selection
Incorrect product selection can lead to a range of issues affecting both occupants and the building itself. Impacts include:
Poor Indoor Air Quality
Inefficient ventilation results in stale air, a build-up of harmful pollutants such as Particulate Matter (PM),CO₂ and VOCs, and allergens, which all accumulate indoors. For some people, health issues can be a mild, such as eye, nose and throat irritation. For others, poor IAQ can cause respiratory problems, headaches, fatigue and have an impact on cognitive function. In the worse cases, health issues can be life-threatening and include an increased risk of cardiovascular diseases, increased cancer risk and the aggravation of existing conditions such as asthma or emphysema.
Find out more about Indoor Air Quality.
Increased energy consumption
Poorly selected or sized systems impact on energy efficiency as products need to work harder to ventilate the area. This results in higher energy consumption and larger bills for the end user.
Damage to buildings and possessions
Moisture buildup increases the risk of damp, mildew and mould growth. This can lead to structural damage to the building, as well as damage to furnishings, furniture and other belongings.
Unpleasant indoor environment
Underperforming ventilation systems can create hot or cold spots in the home, making rooms uncomfortable. Poor exhaust ventilation in areas like bathrooms and kitchens can lead to increased moisture damage and unpleasant odours.
Reduced system lifespan and increased maintenance costs
Clogged filters, inefficient fans, or leaking ductwork put extra strain on components, leading to more frequent breakdowns and costly repairs. In addition, motors and fans may burn out prematurely due to excessive workload.
Noise and operational issues
Poorly performing systems may generate excessive noise from struggling fans, incorrectly sealed ductwork and inefficient airflow.
Safety Risks
Weak ventilation can cause a buildup of pollutants including toxic gas such as carbon dioxide, radon, or even carbon monoxide from combustion appliances, creating serious health hazards.
Non-compliance with regulations
Local building regulations may require specific air exchange rates, duct sizing, and energy efficiency standards e.g. compliance with the EU Energy-related Products (ErP) Directive. Using incorrect product data may result in non-compliance with legislation, leading to failed inspections and costly redesigns.
Ensuring correct product selection can prevent costly repairs, discomfort, regulatory non-compliance and safety hazards in the home. This is a key reason why installation price alone should not be the only factor when specifying residential ventilation products. Decision makers must balance installation costs with product performance and ongoing energy consumption in the home.
Why do systems underperform?
Systems can underperform many reasons including:
- The wrong product may have been selected and installed.
- The product may be faulty.
- The system could be incorrectly designed and/or installed.
- The system may be inadequately maintained.
While all these reasons will have an impact, product selection is by far one of the most important aspects when it comes to achieving good results. This is because the best designed and installed systems will underperform if expected product performance does not match manufacturer claims.
If the product data is incorrect, it can lead to serious problems, including:
- Oversized systems: which waste energy and create excessive noise.
- Undersized systems: which fail to provide adequate ventilation, leading to stale air and humidity issues.
- Non-compliance with regulations.
- Duct sizing errors based on incorrect fan capacity or static pressure data can result in uneven airflow and poor distribution.
- Higher energy consumption, higher carbon footprint and higher ongoing running costs.
- Miscalculations can lead to inadequate fresh air supply, causing discomfort and poor indoor air quality
- Humidity control may fail, leading to excessive dryness or moisture problems, increasing the risk of mould and structural damage.
- If ventilation rates are incorrect, combustion appliances (e.g., gas stoves, fireplaces, water heaters) might not get proper airflow, increasing the risk of carbon monoxide buildup.
- Poor exhaust design due to incorrect fan capacity can lead to backdrafting (pulling harmful gases back into living spaces).
- Wrong specifications may lead to premature wear and tear, requiring more frequent maintenance or early system failure.
- Motors and fans may run at improper speeds, causing overheating, excessive noise, and performance loss.
It’s therefore essential to use accurate, verified manufacturer data to make informed product decisions and ensure a safe, efficient, and compliant system.
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How to identify high performing products
A key strategy to identify high performing products, with correct data, is to choose products that have been independently and vigorously tested by an impartial third-party. This is where Eurovent Certification plays a crucial role.
The big benefits of choosing certified products include:
- Guaranteed product performance
- Proven energy efficiency
- Free access to certified data, allowing direct product comparison and selection
- Plus, products enter a surveillance process to ensure the data declared by manufacturers continues to match the data certified by Eurovent.
For residential ventilation systems, verified data allows decision makers to weigh up product performance and energy efficiency. It’s crucial in deciding if the installation cost provides true value over the lifecycle of the product. It’s also crucial in safeguarding against poor IAQ – protecting the building occupants, the building structure and the reputations of everyone involved in the specification, design, installation and maintenance of the system.
Key Eurovent Certified Performance programmes for residential ventilation systems include:
Residential Air Handing Units
Aimed at MVHR systems, the programme uses the EN 13141-7:2021 test standard to prove product performance, energy efficiency and compliance to European Standards including the ErP Directive. The programme uses a mix of laboratory tests, software selection checks and data evaluation to assess products. From 2026 the programme will also include factory audits to ensure production line quality.
Indoor Air Quality and Energy Efficiency
This programme is aimed at ventilation systems in residential dwellings in individual housing, with an air flow rate < 1000m3/h. It helps specifiers find a balance between the energy performance of systems (e.g. heat loss induced by air renewal and consumption of the electric motor), and Indoor Air Quality performance.
Conclusion
Prioritising installation price over product performance and energy efficiency can have significant long-term consequences for both HVAC professionals and end users. While a lower upfront cost might seem appealing, it often leads to higher energy bills, reduced comfort, more frequent maintenance issues, and a shorter system lifespan. For professionals, recommending subpar systems can harm their reputation, lead to dissatisfied clients and result in costly callbacks. In contrast, investing in high-performance, energy efficient systems ensure reliable operation, regulatory compliance, and lower total cost of ownership. Ultimately, quality pays off - in comfort, IAQ, savings, and peace of mind.
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