Why do I Need MVHR? You may be asking yourself. We've written this article to clear up that question, and more! So kick back, relax and tuck into a healthy dose of information, to help you decide whether or not you need MVHR, and why!
Mechanical Ventilation with Heat Recovery (MVHR) is a whole home ventilation system. It works by extracting the stale, moist, and polluted air from the inside of your home or other property. It then resupplies with fresh, filtered air.Â
At the same time, the air travels through a heat exchanger. This then transfers a large percentage of the heat energy from the extracted air to the incoming air, resulting in a more energy-efficient building when installed correctly.
This creates a more comfortable, condensation and mould-free environment year-round.
Read more about this in our previous article! What is MVHR?
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MVHR meets Building Regulations for new properties and retrofits under System Four of Building Regulations Part F.
Moreover, when you build a new property or retrofit an existing property, it is important you comply with building regulations.
Part F of the Building Regulations, covers installation, inspection, testing, commissioning, and the provision of information pertaining to and installing fixed ventilation systems in your home or other property.
Approved documents provide you with all the guidance you need on how to accurately meet these regulations.
The most important approved document for MVHR is Approved Document F (Part F). This document gives you guidance on how you must meet building regulations that apply directly to ventilation.
Part F states that you must provide adequate ventilation to prevent excess condensation buildup. This buildup could damage the structure of the property. It also ensures that airflow throughout your property maintains adequate levels of indoor air quality.
Every room in a property should have adequate ventilation for health reasons. Each type of room has its own ventilation requirements.
MVHR is listed as a key method of ventilating a property in Part F. Heat recovery provides fresh, filtered, clean air, while extracting stale, moist air out of the wet rooms of a home in an energy-efficient manner.
Wet rooms include kitchens, bathrooms, and utility rooms.
Trickle vents or background ventilation is not required with an MVHR system.
New homes are becoming more airtight due to a variety of efficiency measures, like insulation, draught-proofing, and double glazing. This lack of natural ventilation allows moisture from day-to-day activities (cooking, cleaning, breathing, etc.) to build up with no means of escape. This moisture collects on cold surfaces, like windows and external walls, causing condensation which creates dampness, and mould growth which contributes to poor IAQ (Indoor Air Quality), and in addition potential damage to your property.
To summarise, MVHR systems come with many benefits, such as:
Read more about the problems caused by condensation in a previous article!
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Using an MVHR heat recovery system can recover up to 90%+ of otherwise wasted heat energy. Furthermore, this recovered energy can reduce your heating requirements by up to ~25% with a well-installed system.
Depending on where you buy, your initial investment could pay for itself within 5 years. Factors like air tightness do however come into the equation, causing this efficiency to drop, and, generally, the leakier the property the less efficient.
An office building using a heat exchanger above 80% efficiency can save around 30% on heating bills. The cost of running a heat recovery system is usually less than 10p per day.
MVHR systems are highly efficient systems, that recycle thermal energy used in your home, reducing your carbon footprint and saving money on your bills.
What's more, how much depends on your property and how airtight it is, the more airtight the more efficient your system will be.
Generally speaking, an older property is going to be less airtight than a newer one.
Read more about this in a previous article.
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Of course, as with everything, there are some disadvantages to an MVHR system, some of which are:
