Indoor air quality and mould reduction solutions

Olympic Construction do not sell ventilation units/ systems, using the internet or mail order as other companies do, the reason for this being quite clear, as BPEC qualified domestic ventilation installers, we are well aware every property and situation within a property will be different, no two families live the same. There are thousands of consumers with expensive uncalibrated equipment installed by unqualified contractors, which does not address the real cause of the dampness and mould affecting the property, one thing which is standard is we all produce moisture, so following a detailed inspection, of your property which will include testing any installed systems, our qualified surveyors  we will provide you with a written report, which will detail the issues and a cure, there are many forms of ventilation systems which are available, and can also be very effective in certain situations.

Indoor mechanical ventilation fall into four main categories:

  • Back ground ventilation and intermittent extraction fans.
  • Passive stack ventilation.
  • Continuous mechanical ventilation.
  • Continuous mechanical supply and extract heat recovery.    

System 1 intermittent extract fans

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This is the common type of extraction fan most people are familiar with. They are turned on and off by the user, sometimes via a light switch or infra-red detector, they need to operate at a high air flow rate due to the short period of time in use. As a result they tend to be quite noisy, as well as being less efficient, as they only extract when in use, if its daylight people don’t need to turn the light on, so the fan doesn’t operate.   

The advanced System 1 fans we install, are ultra-quiet and economic to run. They do have a place in modern homes, though we tend to favor System 3 continuous extraction in many cases, as these are more effective, allows lower fan speeds, so are much quieter.

System 2 Passive stack ventilation

This is normally installed in flats and works by using the natural effect of wind speed differences to move air, Bernoulli’s principle the faster air moves, the lower its pressure, generally outdoor air, higher up from the ground, is less obstructed, so it moves faster than the air at ground level, so has a lower pressure, which has the effect of sucking fresh air through the building. A building’s surroundings and the design can greatly affect this strategy, by causing more or less obstruction, and effective back ground ventilation is essential, simply shutting a door, will severally reduce the ventilation effect of this system.  

Photograph showing back ground ventilation closed

System 3 – Continuous extract fans

These come in de-centralise and centralised form. They are ‘on’ all of the time, though at a very low setting, which offers great 24/7 air changes.

As they run continuously they are set to run at lower speeds, so are much quieter whilst being effective, an example being  an intermittent fan from system 1, installed in a kitchen away from the cooker, is required to remove a minimum of 60 liters of air per second, a continuous running system 3 fan can be set at 13 litres of air per second and still be as, if not more effective.    

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Our adaptable, whisper quiet extract fans is guaranteed for 5 years, where multi room extract is required, a centralised extract system in the loft is a great option.

They also have a boost function, which can be automatically or manually switched for those times where a need occurs, such as when cooking, or showering. In effect system 3 ventilation acts almost like a fireplace will have done, when installed with effective back ground ventilation, allowing air to escape from the property all the time, but in a controlled way. The home stays fresh and airy, without the draft or heat loss, associated with a solid fuel fire.

System 4 – Continuous extract ventilation, with heat recovery.

These systems are more costly to install, as there is twice as much ducting and the units are more expensive. However, much of the cost is recovered in saved energy, which would otherwise be wasted.

They also supply filtered air, rather than air simply being drawn into homes via windows and trickle vents, so where asthma or hay fever sufferers are concerned, there are major benefits.

How it works

Moisture loaded air is extracted from a kitchen or bathroom, replacement air is drawn into the mechanical ventilation heat recovery unit (MVHR), from outside, which will be cooler in winter, which is then passed through an advanced heat exchange unit, the majority of the heat being drawn out of the house is recovered at this point, and pre-heats the dry filtered air being delivered into the habitable rooms within the property, when installed and calibrated correctly, this system provides an economical and environmentally friendly method of effectively ventilating your home. 

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Other ventilations system available subject to the problems, construction detail and budget.

Whole House Ventilation systems.

Due to our training, following an inspection we are able to supply, install and commission a large number of effective innovative ventilation systems. These include Nuaire Eco Positive Input Ventilation (PIV), Nuaire were the inventers of the PIV system and have advanced this effective method of ventilation with a number of high quality units, as far as we are aware, Nuaire are the only manufacture offering a 7-year guarantee on their ventilation units.

Moisture loaded air is extracted from a kitchen or bathroom, replacement air is drawn into the mechanical ventilation heat recovery unit (MVHR), from outside, which will be cooler in winter, which is then passed through an advanced heat exchange unit, the majority of the heat being drawn out of the house is recovered at this point, and pre-heats the dry filtered air being delivered into the habitable rooms within the property, when installed and calibrated correctly, this system provides an economical and environmentally friendly method of effectively ventilating your home. 

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Nuaire Dri-Master Eco unit
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PIV and how it works, pushing fresh air in and poor air out

Following our inspection we match the correct unit to the size, layout and occupancy of the property, to achieve the recommended number of air changes per hour (ACH). As detailed within table 1.1b of Approved document F

Nuair’s PIV whole house ventilation units supply pre-filtered air to remove pollen and other particulates, due to the installed filter, normally the air is drawn from the loft space. The air can be pre-heated, however, this is rarely needed, as on average the air in a loft space is a few degrees higher than the air outside, due to the solar effect of the sun, absorbed by the roof structure, and heat moving from the habitable areas of the property below. The air enters the property via a specially designed diffuser installed within the ceiling, normally located on the landing, as this is central to the property.

PIV’s have limitations, there is no 100% guarantee to cure condensation related issues as some will have you believe, normally those companies which sell them to you directly via the internet, without ever inspecting your home, the truth is they may not totally cure condensation in your home, but will reduce the risk, as we all still produce moisture vapour, by breathing, the PIV units should be used with your heating system, in properties which are incorrectly heated or not heated, they can sometimes make the matters worse.

Single room heat recovery systems. (SRVHR).

In some cases, the issues may only be limited to one area of the property, such as an out rigger or attic bedroom, in this situation the alternate flow single room extract unit with heat retention model can be very effective. This ventilation unit acts similar to a combined PIV and an extract system in one room. Air is extracted through the wall mounted ventilation unit for a pre-defined period of 70 seconds, then the unit stops and works in reverse, drawing air into the room, through the same duct

Installed within the duct is a highly efficient ceramic heat exchange module, the heat from the exhausted air which passed through the module is retained and is transferred to the incoming dry air.  Other less efficient systems are available which use twin ducts placed side-by-side or one-above-another with two fans, these consuming more power and so are less energy efficient, but also present a risk the air short circuiting, due to the close proximity of the inlet and exhaust ports.

Our Single Room Ventilator with heat recovery mode is a revolution in indoor air quality

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As part of the survey we will establish the correct location and type of extraction system required, its not as simple as installing a fan in the wall, ideally a fan located in bath/ shower room may need to be SELV rated  (Separated extra low voltage) not exceeding 25Vac subject to location,  IPX4 rated fans can be installed in this area, if deemed safe by the manufacture with suitable protection by a 30ma RCD unit, and should be calibrated to remove

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a minimum of  15L/PS, this can be reduced to 8L/ps when a continuous extract unit is installed, with boost facility.

The building regulations Part F require that any equipment which is capable of being adjusted to variable performance must be ‘commissioned’ correctly, by a suitably qualified person (Bpec Qualified). This is a process which we’ve included in our ventilation installations, which cannot be provided by a company selling ventilation over the internet, commissioning means visiting and surveying your home correctly, recommending the right system, installing the equipment correctly, adjusting and checking it’s performing as designed when completed, finally, ensuring the end user has the documentation, instructions to use and where to obtain maintenance information and advice, if required.

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Would you like to talk?

If you have any questions please call us on Oldham 0161 633 9860,
Wilmslow 01625 900 800
or contact us and we will be happy to answer any of your questions or make arrangements to undertaken an inspection.