A Guide to Ventilation for Self Builders

Let Your New Home Breathe!

Unfortunately ventilation is still a much underestimated element of a self build project. However, in striving to design and develop ever more energy efficient and increasingly air tight homes, the requirement for sustainable and low energy ventilation within self build projects and general new build construction is vital. Not only that, in choosing the correct ventilation you will be able to keep your new home healthy and fresh, creating an ideal environment all year round, free from condensation, mould and other indoor air quality problems.

Which ventilation solution is best?

There are several options available, all of which comply with current building regulations, however the right solution will depend upon a number of factors:

1. The cost and the amount you are willing to spend
2. The air tightness of the property
3. The importance you place on energy efficiency
4. Type of property being built and potential space restrictions
5. Aesthetics
6. Noise
7. Households with asthma/allergy sufferers

Tight budgets

System 1: Intermittent extract fans with background ventilators.

The cheapest option in order to comply with building regulations would be extract fans and trickle vents in the windows. The extract fans would be located in the wet zones of the property – kitchen, utility room, bathrooms and ensuites. However, this is not the most energy efficient method owing to the heat loss incurred through the extract fans. Also, in terms of aesthetics, trickle vents in the windows are not always desirable and extract fans can be noisy, especially if they are not regularly maintained. EnviroVent offer the stylish range of SILENT bathroom and kitchen fans, operating with exceptional performance and the minimal sound levels. To learn more about the range click here.

Click here to view EnviroVent’s full range of kitchen and bathroom extract fans.

System 2: Passive stack ventilation.

This is a non-mechanical form of ventilation whereby vents are located in wet zones and use the principle of convection to allow the movement of air via currents. Background vents need to be installed in conjunction with passive stack. The downside, however, is the fact that the airflow rate is weather dependant and there is a risk of either over ventilating or under ventilating.

System 3: Mechanical Extract Ventilation (MEV).

This is a continuous extract system designed with multiple extract points to draw moisture-laden air out of the wet zones through a central unit before being ducted out to atmosphere. This negates the requirement for numerous extract fans throughout the property and can therefore be a cheaper and quieter option if the property has a large number of wet rooms. In addition, continuous running MEV systems do not require background vents.

To find out more about the EnviroVent MEV Spider, click here.

System 4: Mechanical Ventilation with Heat Recovery (MVHR)

Heat recovery systems work by extracting the stale, moist air out of the wet rooms, which is ducted to a central unit, normally located in a loft space of a house or a utility room or cupboard in an apartment. This extracted air passes over a heat exchanger before being ducted to outside. Simultaneously, fresh air is drawn into the unit from outside via a G4 filter and is warmed by the high efficiency heat exchange cell. This tempered, fresh air is then delivered through supply vents into the living, dining and bedroom areas. This system maintains a stable humidity level, free from condensation and mould. Sufferers of asthma and other respiratory problems should find this method of ventilation significantly beneficial.

Heat recovery systems negate the requirement for background ventilators and extract fans. The cost-effectiveness of the system depends upon its efficiency. In a well insulated and particularly air tight house, the efficiency will be much higher than that of a ‘leaky’ house. That is why with stricter building requirements for tighter homes, energy-conscious self-builders are choosing heat recovery for all year round efficient ventilation. In addition, for self-builders who are extremely energy-conscious and are looking to design and build to specific construction standards such as PassivHaus or Code for Sustainable Homes level 4 and above, MVHR is one of the only options to satisfy the requirements.

EnviroVent offer a full range of energy efficient, low maintenance heat recovery systems to suit all kinds of properties. Click here for more information.

System 5: Systems with BBA accreditation.

Positive Input Ventilation which has been accredited with BBA certification also complies with building regulations. The EnviroVent positive input ventilation units are sophisticated whole home ventilation and condensation control units. By drawing in fresh, filtered and clean air from outside, the units gently ventilate the home from a central position on a landing in a house or the central hallway in a flat or bungalow.

Moisture laden air is diluted, displaced and replaced to control humidity levels around 55%. This significantly reduces or eliminates surface condensation, the main cause of mould growth. With lower humidity levels, dust mite populations are also substantially reduced to provide a significant improvement in the health of asthma sufferers and general indoor air quality.

Trickle vents are not required, however wet zones that are situated remotely from a central hallway may need extract fans to be installed. Positive Input Ventilation is an all year round, whole house ventilation system that is a cheaper option than heat recovery for self builders. The systems can also be extremely energy efficient, providing heat distribution benefits, which can save annual space heating costs by 10%.

For more information on input ventilation and to learn about the EnviroVent positive input ventilation systems and multiple input ventilation systems (MIV®), please click here.