Yes, you can turn off an MVHR system; however, it’s strongly advised against doing so. Turning off your Mechanical Ventilation with Heat Recovery unit can lead to poor indoor air quality, a buildup of condensation, and the potential for mould growth, which can damage your home’s fabric and pose health risks. It also defeats the purpose of the system.
Turning off your MVHR unit might seem like a straightforward way to save on electricity or reduce noise, but it’s a decision that can have significant, and frankly, expensive repercussions for your home and health. It’s a bit like buying a premium, high-efficiency car and then choosing to push it everywhere. It fundamentally defeats the purpose. Therefore, understanding why these systems are so crucial, especially in modern, airtight UK homes, is the key to appreciating why they should be left running continuously.
The Vicious Circle of Poor Ventilation and Its Impact on UK Homes #
In the UK, our homes have become progressively more insulated and airtight over the last few decades. This is a brilliant thing for energy efficiency and reducing our heating bills, but it creates a new, silent problem: what happens to the air inside? Historically, our homes were “leaky,” meaning air would naturally flow in and out through gaps around windows and doors, providing some level of ventilation. This is no longer the case. We’ve essentially put our homes in a big, warm, energy-efficient bubble.
Therefore, the air inside gets stale, filled with all sorts of nasties. Think about it. We’re constantly producing moisture through daily activities like showering, cooking, and even just breathing. A typical family of four can produce up to 10 litres of water vapour every single day! Furthermore, this moisture, along with pollutants like volatile organic compounds (VOCs) from furniture and cleaning products, carbon dioxide, and allergens, has nowhere to go. When you turn off your MVHR, you’re trapping all of this indoors. Consequently, the air quality plummets. It’s like being in a car with the windows up in a traffic jam; it gets stuffy and unpleasant very quickly.
The Science Behind MVHR: A Necessity, Not a Luxury #
The primary job of an MVHR unit, like VENTI’s RESPIRO system, is to provide continuous, controlled ventilation. It works by simultaneously extracting stale, moist air from “wet rooms” (like bathrooms and kitchens) and supplying fresh, filtered air to “dry rooms” (such as living rooms and bedrooms). The magic happens in the heat exchanger, which is the heart of the unit. As the two air streams pass through, the outgoing warm air transfers up to 95% of its heat to the incoming fresh, cold air, all without mixing the two streams. This means you get a constant supply of fresh air without losing your expensive heated air, which is a game-changer for energy efficiency.
Consider the data. According to a study by the BRE (Building Research Establishment), heat recovery ventilation systems can reduce a home’s heating demand by as much as 30%. By turning the unit off, you’re not just stopping the ventilation; you’re effectively throwing away that potential energy saving. In fact, you’ll likely end up spending more on heating as you try to combat the damp and cold caused by inadequate ventilation. A study published in the Journal of Building Engineering found a direct correlation between a lack of proper ventilation and an increase in energy consumption and indoor air humidity, which leads to mould growth. Mould spores thrive in humid conditions, and once they’ve taken hold, they can be a real nightmare to remove. They also pose serious health risks, particularly for those with respiratory conditions.
The Hidden Costs of Poor Ventilation #
Many people think turning off their MVHR will save them a few quid on electricity. A typical domestic MVHR unit consumes around 30-60 watts, which is roughly the same as a lightbulb. It’s a tiny amount when you consider the benefits. On the other hand, the costs associated with not running it are substantial. For instance, the cost of removing mould can run into the hundreds, if not thousands, of pounds, depending on the severity of the infestation. Moreover, the long-term damage to your property’s structure, like timber frames and plaster, can be even more expensive to repair.
Another point to consider is the impact on your belongings. Furniture, clothing, and even books can become damp, musty, and damaged. It’s a silent, insidious form of decay. Furthermore, the health implications are perhaps the most concerning. The Royal College of Physicians and the Royal College of Paediatrics and Child Health have highlighted the link between damp and mouldy homes and respiratory problems, including asthma and other allergic conditions. Ultimately, you’re not just turning off a machine; you’re turning off a system that safeguards your home and your family’s well-being.
By turning off your MVHR, you’re opting out of the controlled, continuous process that these systems are designed for. You’re effectively reverting to the days of relying on “natural” ventilation, which simply doesn’t work in modern, well-insulated homes.
Leaving your MVHR system on is the most effective way to ensure a healthy, comfortable, and energy-efficient home, so for all these reasons, we always recommend keeping it running.