Mechanical Heat Recovery Ventilation

Mechanical Heat Recovery Ventilation (MHRV) systems work by extracting warm, moist air from bathrooms, shower rooms and kitchens via a system of ducting which passes through the heat exchanger (usually in the loft space) before being expelled outside. Fresh incoming air is preheated via the exchanger and ducted inside into the habitable rooms in the house such as the bedrooms and living rooms. It is primarily a ventilation system but with the added benefit that it is recovering heat from the house which would otherwise be lost by opening windows. The heating load of the main heating system in the home will be reduced as a result of having a MHRV system. This further enhances the cost-efficiency of your domestic renewable energy system.

We always recommend installing a Mechanical Heat Recovery Ventilation system as part of a renewable energy system in the home as the improvements to the insulation and air tightness of new homes make it more critical to ensure indoor air quality is maintained, while simultaneously avoiding issues with mould and condensation down the line. The location of the MHRV unit and manifolds in the home has an impact its efficiency. For example, we prefer to have it in a heated space (where possible) as this increases the overall efficiency of the system.

The benefit of having your MHRV system installed by us is that there is one company with full responsibility for the complete renewable energy system. We take great pride in ensuring that your home is comfortable. A correctly balanced ventilation system in crucial in ensuring our heating systems work to the maximum efficiency. The choice of MHRV unit will be carefully selected by us in designing your system to ensure that the operating capacity of the system is in or around 50% where possible.

A further key benefit of MRHV is the health benefits that a ventilation systems can bring to indoor environments. Previous clients with respiratory problems such as asthma have commented on the improvement to their condition after moving into their new “healthier and happier” home. Given the current Covid-19 pandemic good indoor ventiliation has become a critical concern in all buildings.

Demand Control Ventilation

An alternative to the MHRV is Demand Control Ventilation (DCV) which is a fairly new innovation that gives the homeowner more control over the air quality in the home.

This system consists of a central extract unit which has intelligent CO2/H20 and VOC sensors to automatically adjust the volume extract room from each wetroom (via a ducted system and a grille in the ceiling of the room) in order to remove smells and moisture in a fast and efficient way.  Intake air is in the form of wall mounted humidity inlet grilles which will open to let more air in when the DCV unit is in boost mode. When operating normally it will run on trickle mode to keep air moving throughout the house. The advantage of this system is that it is quiet and only boosts when required. Unlike the MHRV System it does not have a heat recovery element and it does not require filters to be changed on a regular basis. It is a good alternative when a full MHRV system is not possible due to duct runs in a house or when a client’s budget is tight. This is a different ventilation concept to MHRV.

The short video below demonstrates the innovative Renson Healthbox DCV system.

The long-term benefits of investing in a mechanical ventilation system 

When it comes to building a new home, it is understandable that everyone is on a budget. What is worth keeping in mind however, is that when the house is built items like ventilation systems can be very hard to retrofit. It is worth giving the ventilation system some serious consideration especially if you can see the long-term gains in terms of the comfort and health of the buildings occupants but also the financial aspect in terms of keeping energy costs low.

We will advise you on which ventilation system best suits your needs when designing a Renewable Energy System for your home. As the ventilation system has as much influence on the comfort of your home as the heating system, having one company design and install both, gives our clients peace of mind that they are getting the best from both systems as they are intrinsically interlinked.

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