"Gary R. Lloyd" wrote in message
...
On Wed, 24 Nov 2004 05:03:26 +1100, "Rod Speed"
wrote:


"Gary R. Lloyd" wrote in message
...
On Tue, 23 Nov 2004 05:02:10 +1100, "Rod Speed"
wrote:


"Gary R. Lloyd" wrote in message
...
On 22 Nov 2004 08:11:30 -0500, wrote:

Gary R. Lloyd wrote:

ASHRAE's "15 cfm per occupant" standard is designed to avoid health
issues.
Smoking, radon, and so on may require more.

For a family of four, that comes to 60 CFM.

You have stated that miners have been shown to pass out at 5 CFM per
person. For our family of four, that comes to 20 CFM.

These 19th century coal-mining experiments were an early basis
for ventilation standards.

You advocate the Canadian model, where the passive leakage is reduced
to 2.5 CFM. Then you would make up the difference by forced
ventilation.

Sure. This also works in most of Europe, and in many books on efficient
home design, eg The Superinsulated Home Book, by Nisson and Dutt
(Wiley and Sons, 1985.)

Is this a fair representation of your position?

Sure. It may be time now to look for better solutions instead of problems.

What are the pros and cons of tighter construction with forced
ventilation versus passive ventilation (leakage), assuming they
both result in roughly the same amount of ventilation?

The obvious pro with tight construction and active ventilation
is that you have real control over the ventilation and can vary
it depending on stuff like CO CO2 and humidity levels.

The only real downside is that you may need some form of
small UPS or internal battery power or failsafe to an automatic
shutter etc if extended periods without power are possible/likely.

I'd personally just have a decent warning system with a completely
unambiguous warning message where its clear what is warning about.

Another real downside is price.

Nope. You'd normally save enough on the lower
heating costs that better sealing produces.

What would be the payback?

Obviously that would vary with the location and how much heating is done.

Of course that's true. Nonetheless it is
the question a homeowner is going to ask.

Its unlikely to be a question worth answering in areas that
need much winter heating. In other words good sealing will
pay for itself, its a tad academic just how long that will take.

What is needed for the discussion is a typical house in a typical
location, with typical construction costs and typical energy prices.

Typical is completely irrelevant. And you will certainly
get a decent payback in areas that do much heating.

If you are anal enough to care, you need to use actual values, not typicals.