HOW TO CONTROL DAMP, CONDENSATION AND MOULD GROWTH

HOW TO CONTROL DAMP, CONDENSATION AND MOULD GROWTH

An article prepared by: John Housden BA(Hons)Arch-Dist MCIM FInstSMM MIEx IoD and Patrick Gallagher FInstSMM CRDS CTIS

Energy efficient continuous running heat recovery ventilation for houses, flats, and bungalows. Part F of the Building Regulations require a supply of fresh air and the removal of pollutants. Using heat recovery ventilation is an efficient and cost effective method of controlling damp, condensation and mould growth in buildings and offers many benefits.

By controlling indoor air moisture content to between 45% and 55% relative humidity at a temperature comfort level of say 20 to 21deg C contributes to the reduction in heat energy consumption leading to environmental benefits for the whole community. Improving indoor air quality helps to reduce the growth of mould spores and house dust mites, which in turn may help the reduction of upper respiratory and other health problems.

These facts are supported from independent studies undertaken by De Montfort University, Portsmouth University, The Energy Savings Trust and The Carbon Trust. For example, stated in a paper prepared by Tom White at De Montfort University entitled “Health Benefits Programme Feasibility Study”:- ‘Heat recovery ventilation is proven to recover waste heat that is lost during house ventilation. Traditionally, fans that are used to remove moist air from homes, also remove the energy in moist air.

Heat recovery ventilation recovers (most of) the waste heat by using the warm stale air to pre-warm the incoming fresh cooler air, by both passing through a heat exchanger.’ ‘This study also provided proof of health improvements: – less use of asthma pumps; general breathing improvements; children happier and more comfortable; fewer visits to the doctor. ‘Other benefits show: – a reduction in the cost of decorating and property maintenance; lowering of household expenditure on heating, therefore reduction of carbon emissions.

People can survive for up to a few weeks without food, a few days without water, but only a few minutes without air. Every one of us inhales and exhales about 20,000 litres of air every day. Most people in the industrialised world spend up to 80% of their time indoors. The human body alone gives off 2-5 litres of water vapour every day, plus clothes washing, bathing and cooking, leading to an average of 16litres of water per four person family. The main effects of excessive moisture in rooms are mould and the breeding of bacteria, allergens and house dust mites.

With good thermal insulation, double glazed windows and modern boilers, rooms are often nearly airtight; the quality of the room air deteriorates very rapidly unless there is suitable provision for ventilation. As a result, the concentration of pollutants and moisture in the room air, absorbed into the walls, ceilings, floors, furnishings, rapidly increases. This adversely affects the well being and health of the occupants and in the long run it may also damage the structure of the building.

To get inside temperature to a comfort level takes more energy when the air is moist than when it is at a controlled to 50% relative humidity level. Likewise, most building fabrics being micro porous, effectively reduce U values. So dryer air to 50% RH rooms uses less energy to heat than when the RH is higher, and with improved U values, less warmth escapes from the walls again lowering heat energy requirements.

John and Patrick have between them over eighty years in the social housing market with over fifty years of those in the damp and ventilation business. Patrick has specialised in heat recovery ventilation from product design, development and production. Over the years, they have undertaken thousands of damp and condensation surveys, and make recommendations to householders and social landlords to help control and eradicate dampness, condensation, mould growth, allergens and house dust mites. Patrick is Chairman and Technical Director of Kair Ventilation Ltd and John a Regional Manager

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