Are Mechanical Ventilation with Heat Recovery (MVHR) systems worth it? It can be a tricky question. While the answer to this can vary from property to property, generally speaking, Yes! A well-installed MVHR (Mechanical Ventilation with Heat Recovery) system will offer substantial savings on your heating bills when compared to the use of normal bathroom fans and ventilating by opening windows.
Another important thing to consider is Indoor Air Quality (IAQ). This can be dramatically improved using MVHR, improving the health and well-being of residents of, or visitors to, a property.
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 it with fresh, filtered air.
At the same time, the air travels through a heat exchanger. This 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?
Using an MVHR heat recovery system can recover up to 90%+ of otherwise wasted heat energy. 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. 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.
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Over the past decade, the demand for well-insulated buildings has risen significantly. Houses that are well insulated but not also well ventilated can find themselves with poor indoor air quality.
A lack of fresh air can result in condensation, damp, mould and a build-up of dust in a property. Side effects of this include unpleasant smells and a build-up of toxic gases which can lead to health problems such as asthma and other respiratory problems.
Installing an MVHR system in your new build, or retrofit will allow you to have a constant supply of fresh air. This air will be filtered, reducing mould and condensation, while recovering otherwise lost heat energy from the extracted air.
MVHR systems come with many benefits, such as:
There are many aspects to take into consideration when planning an MVHR system for your property. Some of these include:
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For old properties retrofitting is a possibility, however, it comes with its difficulties. Older houses are generally less airtight than newer builds, and to get the largest benefits from an MVHR heat recovery system, you need a property to be as airtight as possible.
Older buildings are often leaky, with various background ventilation systems built in, causing them to not be particularly airtight. Many of these buildings get heavily insulated and have double glazing installed, reducing draughts and increasing air tightness. While great, this creates its own issues, such as damp, mould and condensation.
MVHR systems can help reduce or eliminate these issues.
There will be occurrences where not all rooms in an older property can have MVHR ducting run directly to them due to their construction. However, it will be possible to install it on the top floor, allowing for bedrooms and bathrooms to be condensation and mould-free.
Installing MVHR into a new build is much simpler, and is a great investment. It will improve indoor air quality, lower your heating costs and reduce condensation.
This will also futureproof the value of your home, as it meets Building Regulations. Yet another reason that MVHR systems are worth it.
On average, the lifespan of an MVHR unit will be around 15 years. This does not however mean that the whole unit will need replacing after 15 years. Many individual part defects can be solved by replacing that part.
People sometimes choose to replace their unit much sooner than that 15-year time frame. This is simply because newer units are often more energy efficient than older units, and provide better performance.
Hopefully, this article has helped you decide that for yourself. We think the benefits of MVHR speak for themselves, but we don’t know your project!
In summary, for older homes, MVHR can increase efficiency greatly even if they are a little “leaky”. In new builds, MVHR will be a necessity to lower condensation and improve indoor air quality in a more air-tight environment.
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