Heat Recovery Ventilation for New Builds: Meeting Modern Building Standards in the UK

As UK building regulations become stricter on energy efficiency and indoor air quality, new homes are now built to be extremely airtight and well-insulated. While this improves thermal performance and lowers energy bills, it creates a serious challenge: how to ensure proper ventilation without wasting heat.

Mechanical Ventilation with Heat Recovery (MVHR) systems are now seen as essential for meeting these challenges. More than just an added luxury, they are a key component in complying with UK Building Regulations (Part F and Part L) and ensuring a healthy, energy-efficient home.

This guide explains why MVHR systems are essential for new builds, how they work, and what homeowners and developers need to know when planning installation.

Explore more about professional installations on our Heat Recovery page.

Why New Builds Require Heat Recovery Ventilation (MVHR)

Modern Airtight Homes Need Controlled Ventilation

Today’s new builds are constructed with high levels of insulation, airtight materials, and double or triple glazing to meet energy efficiency targets. But while these designs prevent heat from escaping, they also trap stale air, moisture, and pollutants indoors.

Without continuous ventilation, homes can quickly suffer from:

• Condensation on windows and walls.
• Damp and mould growth in kitchens, bathrooms, and bedrooms.
• Accumulation of airborne pollutants, dust, and allergens.
• Excessive CO₂ levels, leading to poor air quality.

MVHR systems solve this issue by providing a balanced, energy-saving airflow that continuously extracts stale air while supplying filtered, fresh air.

Meeting UK Building Regulations (Part F and Part L)

Part F of the Building Regulations requires that homes have adequate ventilation to ensure fresh air for occupants. It sets out airflow rates and guidelines for maintaining healthy indoor environments.

Part L focuses on energy conservation, mandating that homes be built to high standards of airtightness and thermal efficiency.

An MVHR system enables new homes to achieve both of these standards by:

• Providing continuous, controlled ventilation to meet Part F airflow rates.
• Recovering up to 90% of the heat from extracted air, supporting Part L's energy efficiency goals.

Energy Savings and Reduced Bills with MVHR

Heating incoming fresh air is one of the biggest energy costs in an airtight home. MVHR systems reclaim heat from the stale air being removed, using it to warm the fresh air coming in — without mixing the two. This process significantly reduces the load on your heating system, resulting in lower energy bills.

How MVHR Systems Work in New Builds

An MVHR system works as a whole-house ventilation solution, designed to move fresh and stale air continuously through separate channels.

The MVHR Process

1. Extract stale, humid air from bathrooms, kitchens, and utility rooms.
2. Draw in fresh air from outside, passing it through filters to remove dust, pollen, and pollutants.
3. Pass both airstreams through a heat exchanger, where heat from the outgoing air is transferred to the incoming air.
4. Distribute filtered, pre-warmed air to living rooms, bedrooms, and other areas — without drafts.

Benefits of Installing MVHR in New Homes

1. Healthier Indoor Air Quality (IAQ)

MVHR systems supply constant filtered fresh air, essential for modern airtight homes. They help to:

• Remove airborne pollutants, VOCs, and allergens.
• Maintain healthy humidity levels, preventing condensation and mould.
• Provide fresh air without needing to open windows — ideal for homes in urban or high-pollution areas.

2. Lower Energy Bills and Reduced Heat Loss

By recycling heat from outgoing air, MVHR units dramatically cut down the energy required to warm fresh air, leading to real savings on heating bills.
They work especially well when paired with low-temperature heating systems like underfloor heating or heat pumps.

3. Year-Round Comfort and Temperature Stability

MVHR provides continuous airflow, ensuring rooms remain comfortable without drafts or cold spots. Fresh air is supplied at near-room temperature, so homes stay warm in winter and cool in summer.

4. Building Regulation Compliance and Future-Proofing

As building regulations tighten around energy use and ventilation, MVHR ensures compliance while future-proofing the home for evolving environmental standards.
A properly installed system also enhances a home’s SAP (Standard Assessment Procedure) score, often a requirement for building control and mortgage approval.

Key Components of a Whole House MVHR System

An MVHR system is made up of several integrated components that work together to provide optimal ventilation.

• MVHR Unit (Heat Exchanger): The main unit that contains fans, filters, and the heat recovery core.
• Ductwork Network: Delivers fresh air to living spaces and extracts stale air from wet rooms.
• Supply and Extract Valves: Adjustable outlets placed discreetly in ceilings or walls.
• Filters: Typically G4 or F7 grade, capable of trapping fine dust, pollen, and external pollutants.

Design and Planning for MVHR in New Builds

1. Early Planning Is Essential

For MVHR to work efficiently and quietly, planning during the design phase of a new build is crucial. This ensures the system is properly integrated into the building's structure, making duct routing and unit placement straightforward and discreet.

2. Allocating Space for the MVHR Unit

The MVHR unit is typically installed in a utility room, plant room, or loft space. Modern units are compact and quiet, suitable for domestic use.

3. Designing Duct Routes

Ducting should be designed to:

• Minimise sharp bends for smooth airflow.
• Avoid long runs that could reduce efficiency.
• Fit neatly into walls, ceilings, or floors to maintain the aesthetic of the home.

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