ventilation in a bathroom

[Mary Fisher]

Quite.

[Harry Bloomfield]

David Hansen explained on 23/04/2006 :

It can, however forced ventilation can do it better, more reliably and less wastefully - draw the moist air out directly.

Windows are not often well placed to where the moist air is produced, such as over a cooker. Windows are highly dependent upon which way the wind is blowing, if it happens to be blowing at the window the moist air can be blown through the rest of the house.

A well placed fan can draw the moist air straight out from source and its small current draw is usually more than offset by the savings in lost heat through an open window.

[David Hansen]

On Sun, 23 Apr 2006 21:25:18 +0100 someone who may be Harry Bloomfield wrote this:-

Debatable. There are many badly designed mechanical ventilation systems that don't.

Ditto.

Again debatable. Some mechanical ventilation systems waste a lot of energy by being too powerful.

[The Natural Philosopher]

Part of the regs mate.

[The Natural Philosopher]

Actually, it almost certainly won't..

The requirements for fans are for RAPID dispersal of SHORT TERM extra localised humidity without excessive heat loss.

In an ideal world you might do it with a convective heat exchanger - hots sticky air rising up, and warming cold dry air on the way in...in reality, a fan is cheaper...and its arguable as to how 'natural' sucjh a system is anyway.

Fans are totally natural. Every bee comes with four. :-)

[David Hansen]

On Sun, 23 Apr 2006 22:18:42 +0100 someone who may be The Natural Philosopher wrote this:-

An assertion that is made from time to time, usually by those who do not understand properly designed natural ventilation but are instead wedded to old-fashioned energy-intensive concepts. The future is with those that reduce energy intensity.

[marvelous]

A 30 watt fan for 15 minutes is hardly energy intensive compared to what is consumed by everything else in the modern house. 1000 watt tvs and 500 watt computers are not unusual.

What about the wasted heat energy with the permanent drafts you seem to be proposing?

Fans at least make sure the damp air / bad smells are going in the right direction and quickly. Leaving a window open will not stop damp air coming into the rest of the house under the door.

[David Hansen]

On Mon, 24 Apr 2006 08:00:56 GMT someone who may be marvelous wrote this:-

It all adds up.

There are indeed more energy intensive bits of equipment, but computers and televisions, the examples you gave, have reduced electricity consumption due to the introduction of more modern displays.

You are the one proposing permanent drafts, not me.

Only if it is designed, installed and operated correctly.

Not if it is designed, installed and operated correctly.

The idea that every problem should be dealt with by mechanical means is very 1970s. Our understanding has moved on since then.

[Mary Fisher]

Indeed. I often remember the adverts for 'Mrs 1970's' oil heated house, people wearing hardly anything indoors with snow outside - as though such a life style were desirable. I thought it was wasteful and unsustainable even then.

The acceptance of that understanding hasn't moved as fast :-(

Mary

[The Natural Philosopher]

He saw fit to omit the part of my post where I posited the actual cost in energy and materials to MAKE a proper heat exchanged 'natural' air ventilation system.

Essnetially what a house ventilation system should consist of is an inion of rooms inside a dome,through which sticky hot air goes in flues, and cool air is drawn from the outside

And indeed the most energy efficient SHAPE of a house is actually sphere..

Igloos rule OK!

[The Natural Philosopher]

But our ability to perform actual real cost benefit analysis has, it seems, not..