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Lofty whole home ventilation system - any good?

Discussion in 'Building' started by kevin_robson, 12 Nov 2007.

  1. rozzerboy

    rozzerboy

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    Hiya there, ive the same problem with condensation and mould which does not look too great.
    Has any one found the best place i.e the cheapest place to buy a lofty system from???


    Many Thanks
     
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  3. JohnD

    JohnD

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  4. ^woody^

    ^woody^

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    Sometimes, opening the window will not work. Nor will increasing heating, changing heating patterns or insulating - if at all practical, or changing lifestyle.

    The standard answers are banded about, but in practical terms, they are not always practical or possible

    In which case, in the long run a positive pressure system such as the lofty is the best and cheapest option
     
  5. JohnD

    JohnD

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    you may be right of course

    can you give an example of a wet house, and the cause of wetness that cannot be addressed by ventilation and change of habits?
     
  6. ^woody^

    ^woody^

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    A older property which is expensive to heat - eg inefficient electric heating and low family income

    A flat where there is nowhere to dry washing except within it, on an airer.

    Different use patterns or occupancy.

    A property in a general north facing direction with most walls to habitable rooms in a state where they stay cold and retain more moisture than the rest, and most windows allow little solar gain.

    It is also wrong to expect occupants to magically change lifestyles. Unless they are doing something blatantly out of the ordinary, modern life is different to what many [older] properties were designed to cope with

    Ventilation on its own, is only effective if a balance can be struck with the colder, often humid air which goes into the property - assuming that all the internal humid air can be naturally ventilated in the first place
     
  7. rozzerboy

    rozzerboy

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    I had a free survey done from a damp specialist and it is purely condensation. He was saying that he has never known so many people to be getting condensation. He recomended the lofty system to me, so was wondering if i can save some pennies by buying direct from any where???
     
  8. JohnD

    JohnD

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    rozzerboy, have you tried addressing the causes of damp yet?
     
  9. rozzerboy

    rozzerboy

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    I was just asking if any one knew the best place to purchase a lofty was.

    I have a old property and it is a 2 storey flat, hence i have no choice but to dry clothes inside.The cause of damp is purely condensation.
     
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  11. PerryOne

    PerryOne

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    Kevin, please explain the logic of pumping cold air into the upstairs of a home to cure condensation?

    If you want to dilute the warm wet air in your home you traditionally just open a window (this costs a lot less than £400) and let some of the warm wet air out and let some of the cold dry air in.

    The air outside is nearly always drier than the air indoors.

    But opening windows in winter, lets that warm air out, warm air that you will have to pay to heat and lets in cold air that you will need to heat at more cost.

    So why produce water vapour in the first place?

    Why not buy a hygrometer for a few pounds and see how wet the air is in your home.
    One that has an accuracy of + or - one percent and a memory will do the trick.

    Then you can measure progress

    Why not change your life style, stop making so much water vapour and let the problem go away?

    Water vapour that turns into condensation is caused by washing, cooking, drying things on radiators and breathing.

    The process relies on the fact that warm air holds more water vapour than cold.
    Example:
    Warm air at 30 C holds 30 ml of water
    Warm air at 20 C holds 18 ml of water
    Cool air at Zero C holds 5 ml of water
    This is per cubic metre of air.

    You can see that turning your heating down
    or turning your heating off, causes the water vapour in the air to condense onto or into the windows, walls, beds and other furnishings.

    Usually the first sign is windows running with condensation in the morning, where the temperature in between the window and the curtains or blinds has dropped during the night.

    The perfect solution is to hold the same temperature for 24/7 this will cause the warm air to hold the moisture, it will warm the walls and other things and you will have a far more pleasant home.

    You will no doubt have noticed that during the day the warm air moving past the windows helps keep them warm and dry the condensation only forms at night.

    If you have extractor fans in your kitchen and bathroom use them and leave them running for twenty minutes after use or until the humidity has gone away - (you can buy extractor fan with humidity control) this is cheaper than buying new kit to do the same job.

    In any event, pumping in cold dry air, merely pressurizes the home and help push the warm wet air into the walls, making the walls damp and the home unpleasnt.
     
  12. ^woody^

    ^woody^

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    That is incorrect .... and a scientific impossibility

    This system pressurises the home and pushes air out through ventilation openings or adventitious gaps in the structure. But the main thing is that it keeps air moving

    It does not, and can not push "warm wet air" into solid walls to make them damp :rolleyes:

    This is a proven system, and does work
     
  13. PerryOne

    PerryOne

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    Woody, this system and others like it was designed for social housing where the tenants could not be expected to look after themselves and where other people, the tax payers were expected to pick up the bill.
    Used in social housing where exhaust provision is built in -and the system is carefully balanced, the system works.
    In other situations where the tenants/owners pay the bills there is an existing possibility that they will block up the exhaust outlets to save money and the increase in pressure will force the internal environment into the usual holes and cracks in the walls, floors and ceilings.
    As the normal progress of water vapour is always towards a vacuum or the nearest cold surface, then the water vapour will and does make its way outwards towards the cold outside, this leads to interstitial condensation.
     
  14. ^woody^

    ^woody^

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    Firstly, taxpayers do not "pick up the bill" for social housing tenants, any more than the taxpayer picks up the bill for your next hospital visit.

    Secondly, the rest of your post is just plain wrong and demonstrates no understanding of the subject.

    Do you really think that someone with a condensation problem, will have one of these fitted ("where the tenants/owners pay the bills") and then block up the vents so that it does not work?

    How can the "normal progress" of water vapour be towards a vacuum (outer space?) or a cold surface, when water vapour is held in suspension in the air. A cold surface does not automatically mean that air will condense on it, does it?

    Just to clarify ... a positive pressure system pushes air around and out of a property, and on occasions where moist air may condense on a surface, it is of such small quantities that it evaporates again relatively quickly so as not to form excessive surface condensation.

    A permeable material like plaster, or timber will absorb a certain amount of atmospheric moisture naturally, and this has nothing to do with being forced by air pressure into the material

    And don't infer interstitial condensation as a regular occurance, when in reality this form of condensation only occurs in rare cases and under particular circumstances.
     
  15. DampSurveyor12

    DampSurveyor12

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    Dear Kevin,
    I realsie that your original posting regarding the Lofty was some time ago and which I have only just come across.
    My reason for logging onto this site was to make contact and firstly ask what your experience has been with the said unit?
    Also, if it may help, the whole subject of humidity within dwellings and the various effects is often not always clearly understood by many within the Building industry.
    Essentially, humidity which obviously leads to condensation, mould and other problems is a result of four key issues. These are ventialtion, insulation, heating regime and lifestyle of the occupant/s.
    If any one of these factors becomes out of balance there is the propensity for humidity to increase. However, how it actually manifests depends upon a variety of factors which are often related to the dwelling itself e.g. aspect, age, configeration etc etc.
    In my experience positive air units can make a difference but it is essential for each situation to be assessed in order to establish and identify what the most important factors regarding reducing average humidity levels. Ideally the range should be between 50 - 65% RH if it consistently reaches 70% this can be sufficient moisture for mould spores to germinate and colonise wall space and still pockets e.g. behind furniture.
    Like all damp and moisture management issues, what is important is getting an accurate diagnosis in context in the first place so that the house owner can make an informed decision knowing that his or her money will be spent wisely in deal with the problem.
     
  16. kev78

    kev78

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    Hi guys
    This is my first post here so i'll share my experience of the positive pressure system i had fitted on the 12th feb 2009.

    Bought my cottage nov 2007. Cottage is 3 bed with 2 rooms downstairs. Kitchen is open to the stairs and the cooker is in the centre of the downstairs space with very inadaquate(cant spell sorry) ventillation.

    Property is solid wall construction built in 1900 with walls about 2 and a half feet thick.

    Double glazing fitted with less than half having trickle vents.

    So basically it is the perfect storm for condensation.

    Have tried everything suggested on here like opening windows - even in the thick of the snow this year had 2 open all night but still condensation on the walls and windows of the bedrooms.

    Bathroom is also in the centre of the house with no window just a fan.

    Installed good heating which was a waste of money until the lofty because windows were open 24/7.

    Was really at my wits end with the smell, the black marks all over the paintwork within a week of fresh paint being applied and the continual routine of wiping the moisture away and venting the house while we sat indoors in coats.

    Couldn't find much in the way of a forum review that didn't have the things i had already been doing like opening windows, turning on fans to circulate the air etc etc.

    So i took the plunge and got one fitted - the next morning i found mself punching the air in delight. The winows were shut all night but there was no evidenc of moisture aywhere in the house. Even in the bedrooms where i used to be greeted by soaking wet window cills and windows you couldnt see through due to all the water that sat on them.

    When cooking there is still always a window open - but it can be closed as soon as i have finished and the moisture stays away.

    The lofty has worked for me in my property and i would sing their praises to anyone who will listen
     
  17. dave1953

    dave1953

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    The Lofty equlises water vapour PRESSURE within the property and this is why it works, i.e. kitchen or clothes drying room[ which you should not do - use a tumble dryer with external window venting] will have different % Humidity levels to other rooms, leave all doors open and let it do it's work
     
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