Do I Need a Condensation Drain for a MVHR Unit?

Do I Need a Condensation Drain for a MVHR Unit?

Do I Need a Condensation Drain for a MVHR Unit?

In this blog, we will address the question ‘Do I need a condensation drain for a MVHR unit?’

With new buildings being made to be as energy efficient as possible, and the UK aiming for 95% of its electricity usage to be low carbon by 2030, it is imperative to understand how we can make the most of our ventilation. This is where MVHR units come in.

To prevent mould, fresh air should constantly be introduced into your dwelling daily, as it helps to regulate temperature and reduce condensation. Introducing fresh air can be as simple as having a ventilation routine, or installing extractors or MVHR units. Almost all of this is facilitated by ducting.

Is a MVHR unit the same as a heater?

No. MVHR units are a form of ventilation system. Although they have features that can help heating, their purpose is not to create heat like a central heating system. MVHR systems have the primary focus of ventilating, and retaining heat that is lost through ventilation.

MVHR stands for ‘Mechanical Ventilation with Heat Recovery’. This is the formal term, the units that use this technology are generally known as heat recovery units, or heat recovery systems.

As the name suggests, MVHR units provide the function and benefits of ventilation, whilst also finding a way to recover heat that is lost during ventilation, whilst also providing fresh, filtered air from outdoors. They are available in single or multi-room units.

The advantages of heat recovery systems are the following:

  • Temperature sensors ensure that additional heat is not being added to the atmosphere of the home if it is already hot.
  • Heat recovery systems take a lot of the burden from you conducting a ventilation routine. This is ideal for a vulnerable person.
  • Less of a need to use your central heating frequently as the heat generated through your house is recycled through the heat recovery unit.
  • The reduced use of heating as a result of the heat conservation granted by a heat recovery unit can help you save on energy bills.

Should I get a MVHR unit or an extractor fan?

MVHR units are available in single or multi-room units. For this question, we will be comparing an extractor fan to a single room unit.

Both options extract humidity that will form in a room, such as steam in a bathroom. MVHR units will ensure that no heat is lost.

So when it comes to deciding which option is more suitable for you, if your bathroom, or room of installation is always cold, a MVHR unit would be a more appropriate option. Especially if the room in question is difficult to ventilate. A MVHR unit will also provide fresh air to the room.

Do I need a condensation drain for a MVHR unit?

Do I need a condensation drain for a MVHR unit?

Yes. Most, if not all, modern MVHR units do come with a condensation drain, so the only time you may need to purchase one, is if it is a replacement. Condensation drains play a vital part in maintaining the effectiveness of your MVHR unit.

Understandably, the mix of cold and hot air within the MVHR system, as well as the extraction of humid air, can result in condensation occurring in the unit. If this condensation is not removed, it can easily make its way into the ducting, this can cause severe issues such as mould.

This is rectified by directing any condensation to the condensation drain of the unit.

The condensation drain is generally a removable part of the MVHR unit. The idea is to remove the drain when the water is filling it up, and emptying it and putting it back on.

By neglecting to do this, your condensation drain will eventually overflow. This can result in the MVHR unit becoming faulty, and even growing algae and/or mould in the humid areas. The regularity needed to empty the condensation drain will vary based on your home and how much humidity is regularly extracted.

Upon installing your MVHR system, wait for a week and check how much water has collected over that time, from there, you can gauge how often you should empty it.

Can my MVHR unit still work without a condensation drain?

It is unlikely that your MVHR unit will work to the same level of effectiveness without a condensation drain, if at all.

Some units may provide an alert if it doesn’t have its drain attached. Whether it works or not, not attaching the condensation drain will eventually result in faults in the machine. In addition, you will experience mould build-up in the unit and its ducting.

If mould is already an issue for you, having it within your ventilation system can spread and worsen the effects it may already be having on you.

Does MVHR stop humidity?

Humidity can’t be ‘stopped’ from occurring, unless you can control every temperature fluctuation in your vicinity. That being said, MVHR will remove any humidity that can end up forming condensation.

How else can I remove condensation from my home?

How else can I remove condensation from my home?

Removing any condensation that forms in your home is the key step in preventing mould, here are some methods besides MVHR you can employ to prevent the condensation from forming, or from eventually becoming mould.

  • Wiping any condensation you find with a dry cloth.
  • Having a daily ventilation routine.
  • Opening windows when using the shower/cooking.
  • Using a cooker hood extractor when cooking.
  • Allowing for ventilation in the home by not keeping one room closed constantly.

What should I do to remove mould in my home?

If you have unfortunately found mould developing in your home, using a mould surface cleaner, followed by an anti-mould paint is an extremely effective method in removing mould on a surface, and preventing its return for some time.

If mould has already developed, you should first assess how it got there, for example, mould that has arrived because of untreated condensation in a bathroom can easily be prevented from returning once removed.

However, mould that has occurred as a result of structural issues in the dwelling will mean that the issue in question must be addressed, otherwise the mould will return.

Does mould only grow in bathrooms and kitchens?

Not at all. Mould has the potential to develop in any room in the house. Kitchens and bathrooms are just the easiest places they can develop. In terms of other rooms, these factors can be the cause of the mould developing…

  • Poor insulation due to old or damaged windows.
  • Little to no efforts in ventilation.
  • If there are any unsealed openings to the outside, that has potential to develop mould.
  • Leaking pipes can create an unyielding damp spot that can grow mould if left untreated.
  • Damage to roofing tiles or clogged gutters can contribute to mould growing from your ceiling.
  • En-suite bathrooms can greatly contribute to a bedroom developing mould, if the window is left closed, allowing steam to escape into the bedroom.

Invest in condensation solutions today

Invest in condensation solutions today

We at I-Sells endeavour to ensure our customers have all the information they require before investing in our mould solutions. Be sure to visit our blog page to learn about the vast array of factors and issues surrounding ventilation, mould, condensation, and much more.

We hope to have answered the question ‘Do I need a condensation drain for a MVHR unit?’’

We understand you may have more questions, do not hesitate to contact us for more information about whatever you need our help with. If you’d like to email us, click here. For other contact options, see below:

Call us on 020 8463 9696

Visit us at our showroom:


Monday – Friday: 8:00 am to 5:30 pm

Saturday: 9:00 am to 12:00 pm

Sunday: Closed

15 St John’s Parade

Sidcup, Kent

DA14 6ES

United Kingdom

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