“
A Mechanical Ventilation with Heat Recovery (MVHR) unit is a type of mechanical ventilation system used in buildings to provide fresh air while also recovering heat from the outgoing stale air. It’s commonly used in residential and commercial buildings to improve indoor air quality and energy efficiency.
What it does:
An MVHR unit performs two main functions:
Supply Ventilation: It brings fresh outdoor air into the building’s living spaces, ensuring a continuous supply of clean air for occupants to breathe. This helps maintain a healthy indoor environment and prevents the buildup of pollutants, odors, and excess moisture.
Exhaust Ventilation with Heat Recovery: It simultaneously removes stale indoor air from rooms like kitchens, bathrooms, and living areas. As the warm, used air is extracted, the MVHR unit also recovers the heat from this air and transfers it to the incoming fresh air. This heat exchange process significantly reduces the energy required to heat the incoming air during colder months, improving energy efficiency and reducing heating costs.
How it operates:
An MVHR unit operates using a system of ducts, fans, filters, and a heat exchanger. Here’s a general overview of its operation:
Supply Air Intake: Fresh outdoor air is drawn into the MVHR unit through a filtered intake vent. These filters help remove particles and pollutants from the incoming air.
Heat Exchange: The fresh outdoor air and the stale indoor air pass through separate channels of a heat exchanger, usually made of a material with good heat conductivity. As the two air streams flow past each other without mixing, heat is transferred from the warm indoor air to the cooler outdoor air. This preheats the incoming fresh air, reducing the energy needed to heat it further.
Exhaust Air Outlet: The now cooler, stale indoor air is expelled from the building through another duct.
Supply Air Distribution: The preheated fresh outdoor air is distributed through ducts to different rooms in the building, providing ventilation.
Controls: MVHR units typically have controls that allow users to adjust settings such as airflow rates, fan speeds, and temperature thresholds. Some advanced units may even have humidity and CO2 sensors to optimize ventilation based on indoor air quality.
MVHR units are especially beneficial in energy-efficient buildings where airtight construction can sometimes lead to inadequate ventilation. By providing controlled ventilation while also recovering heat, these units help balance energy conservation with indoor comfort and air quality.
It’s important to note that the specifics of MVHR unit operation can vary based on the manufacturer and design of the unit, so it’s recommended to refer to the manufacturer’s documentation for detailed instructions and guidelines.”