OT: Whole house ventilation

Charlie Edmondson · Jun 17, 2005

John Perry wrote:

Frithiof Andreas Jensen wrote:

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:1cmre.591$Pa5.22@newssvr21.news.prodigy.com...

Why are whole house ventilation systems by default "whole house fans"
that suck air out of the house? Why is there no system available at Home
Depot, Lowes or other places that blows air into the house through a
filter and then out the screen doors instead of sucking unfiltered
air in?

When I was small and air conditioning was not yet common, even here in
Virginia, my parents used a huge window fan in one room (where I liked
to spend much of my time). This room was always uncomfortable, so I
asked my father why he did this.

The response was that if he turned the fan around so it would blow into
the room, then, yes, that room would be comfortable, but none of the
other rooms would be. With the fan blowing out, fresh air was always
coming into the other rooms with open windows, making most of the house
more comfortable. The same applies, obviously, to whole house fans,
although I've never had a house with one.

Because, the "Average Consumer" *wants* a big lump mounted in the wall of
his home because that is all he is good for when installing it himself.

But *nobody* kicks a whole in the wall for one of those noisy, ugly,
lumpy
units that the Americans like ;-)

Well, I did, a number of years ago, in the 1930's era house I used to
live in. At the time, I couldn't afford the 10X price differential to
install central air conditioning, ducting, wiring, ...

I still think I did the right thing .

John Perry
Growing up, we went through the whole progression. Our house in Memphis

originally had the whole house fan in the hall. When that thing cranked
up, there was a pretty good breeze through the house, but it didn't help
much in the 95/95 weather.

Then, my folks bought a single window unit, and put it in the living
room. That room kept pretty cool, and with the doors all open, it
reduced the humidity through out the house to help, but at the far end
of the house, it was pretty miserable. I spent a lot of summers either
at the pool, or in the living room reading or watching TV.

Finally, they bit the bullet, and installed central air. We already had
forced air heat, so they only needed to add the condenser in the attic
and the compressor outside. Cool at last...

But it cost a fortune to run!

Charlie

keith · Jun 18, 2005

On Fri, 17 Jun 2005 08:55:21 -0700, John Larkin wrote:

On Fri, 17 Jun 2005 11:16:34 +0200, "Frithiof Andreas Jensen"
frithiof.jensen@die_spammer_die.ericsson.com> wrote:

"Joerg" <notthisjoergsch@removethispacbell.net> wrote in message
news:1cmre.591$Pa5.22@newssvr21.news.prodigy.com...

Why are whole house ventilation systems by default "whole house fans"
that suck air out of the house? Why is there no system available at Home
Depot, Lowes or other places that blows air into the house through a
filter and then out the screen doors instead of sucking unfiltered air in?

Because, the "Average Consumer" *wants* a big lump mounted in the wall of
his home because that is all he is good for when installing it himself.

In Denmark we do not want "the lump" and energy is expensive so we will pipe
the air to the rooms in the house, the outgoing air goes through a
heat-exchanger and the heat pump sucks the heat out of it and uses it to
warm the incoming - in the summer, this is reversed. All the stuff goes in
the attic.

Alternatively, having no attic or a smaller house, one put the compressor
part outside, hidden round the back where the noise annoys the neighbours
more than yourself, and pibe coolant into a fan unit in the ceiling where
the heat bothers them most (livingroom/bedroom). This flow can be reversed
too.

This is standard "central air" here. The remote unit is the air
conditioning compressor and sometimes a heat pump, although direct gas
heating is probably more common. Chillers/heaters are in the attic,
with forced-air ducting everywhere.

Here few have central air-conditioning because forced-air heat is unusual
and the need for AC is minimal. Most have either oil or gas (me)
fired hot-water heat, so the ductwork for central-air is a rather
significant expense. Most here have window units and run them perhaps 30
days over a four month period. For the past few years, I've run mine more
for dehumidification than anything else.

But *nobody* kicks a whole in the wall for one of those noisy, ugly,
lumpy units that the Americans like ;-)

In older houses, people often use a window-mounted a/c unit or two.
Noisy and inefficient, but still a blessing in places where the humidity
and the temperature both idle near 100.

I have a 2-ton unit through the wall downstairs and added a 7000BTU/hr
unit (also through the wall) in our bedroom. Sleep is important. Adding
the ductwork for cental AC would be silly.

The French like those silly portable air conditioners, the ones with the
hot air dump hose that you stick out the window. They're hardly worth
the effort.

I see those in the stores here. What assinine contraptions! The
condenser in the room is just such a good idea.

In our local climate, the San Francisco peninsula, air conditioning is
not universal (essentially unknown in the city itself) and a simple fan
is all you really need to stay comfortable. Now, in the middle of June,
we leave the heat on.

I just turned mine off a week or so ago. However, I did run the ACs for
five days straight. It was hot and muggy. It's also been raining (what's
new) so I can't open my windows.

--
Keith

Paul Hovnanian · Jun 18, 2005

Joerg wrote:

Hello Folks,

This is electrical but quite a bit off topic. But maybe some people who
live in hot climates know:

Why are whole house ventilation systems by default "whole house fans"
that suck air out of the house? Why is there no system available at Home
Depot, Lowes or other places that blows air into the house through a
filter and then out the screen doors instead of sucking unfiltered air in?

I'd think that a "whole house" fan could be built either way: suck air
out (negative pressure) or blow air in (positive pressure).

Thing is, when you use a whole house fan you have to leave one or
several doors open with just the screens between the outside air and the
house. The result is that people regularly find enourmous amounts of
dust and pollen inside because everything gets sucked in. All it takes
is one gentle breeze through a stand of pines. Before you realize the
winds kicking up and rush inside to flip the switch to off it's too
late. Makes not sense to me.

That makes sense. If you operate the house at a slight positive
pressure, you have the opportunity to condition (filter, heat and/or
cool) the air introduced. In order to maintain air flow, you'd have to
provide some means for air to escape. Well-sealed houses have a problem
with this. Heat exchanger systems have an outflow duct which takes care
of this, but with a simple blower, you'd have to open a window or have
an exit duct somewhere. Ideally, the exit duct would be equipped with a
damper that would regulate the interior pressure to keep it slightly
positive.

--
Paul Hovnanian mailto

aul@Hovnanian.com
------------------------------------------------------------------
A mathematician is a machine for converting coffee into theorems.

Joerg · Jun 18, 2005

Hello Paul,

That makes sense. If you operate the house at a slight positive
pressure, you have the opportunity to condition (filter, heat and/or
cool) the air introduced. In order to maintain air flow, you'd have to
provide some means for air to escape. Well-sealed houses have a problem
with this. Heat exchanger systems have an outflow duct which takes care
of this, but with a simple blower, you'd have to open a window or have
an exit duct somewhere. Ideally, the exit duct would be equipped with a
damper that would regulate the interior pressure to keep it slightly
positive.

That would be a nice system. The whole house fan seems to reverse it,
creating a pressure drop. Just imagine the horror scenario when the
fireplace is used and a kid flips on the whole house fan switch.

Regards, Joerg

http://www.analogconsultants.com

Jim Thompson · Jun 18, 2005

On Sat, 18 Jun 2005 18:23:05 GMT, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Hello Paul,

That makes sense. If you operate the house at a slight positive
pressure, you have the opportunity to condition (filter, heat and/or
cool) the air introduced. In order to maintain air flow, you'd have to
provide some means for air to escape. Well-sealed houses have a problem
with this. Heat exchanger systems have an outflow duct which takes care
of this, but with a simple blower, you'd have to open a window or have
an exit duct somewhere. Ideally, the exit duct would be equipped with a
damper that would regulate the interior pressure to keep it slightly
positive.

That would be a nice system. The whole house fan seems to reverse it,
creating a pressure drop. Just imagine the horror scenario when the
fireplace is used and a kid flips on the whole house fan switch.

Regards, Joerg

http://www.analogconsultants.com

480)460-2350 | |
| E-mail Address at Website Fax

Joerg · Jun 18, 2005

Hello Jim,

What! You don't have a chimney fan? I have one on my outdoor
fireplace since the slope of the hill tends to reverse-pressure it by
pouring cold air down the stack.

I don't. And I don't want to. Just imagine what would happen if you had
a nice fire in the stove and then the power goes...

Our flue liner is triple wall stainless and has just the right stack
height for a nice performance.

Regards, Joerg

http://www.analogconsultants.com

Jim Thompson · Jun 18, 2005

On Sat, 18 Jun 2005 23:25:51 GMT, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Hello Jim,

What! You don't have a chimney fan? I have one on my outdoor
fireplace since the slope of the hill tends to reverse-pressure it by
pouring cold air down the stack.

I don't. And I don't want to. Just imagine what would happen if you had
a nice fire in the stove and then the power goes...

Our flue liner is triple wall stainless and has just the right stack
height for a nice performance.

Regards, Joerg

http://www.analogconsultants.com

480)460-2350 | |
| E-mail Address at Website Fax

Joerg · Jun 18, 2005

Hello Jim,

The house fireplace is fine, but the top of the beehive in the
backyard is level with the lip of the adjacent hillside... unless you
have a roaring fire you get smoke out the front.

Yes, those backyard fireplaces aren't that hot. We have a cast iron one
but it'll smoke, too. I believe an old rule is that if a stack isn't
15 feet vertical from the bed of the fire it's unlikely to draft right.

BTW, my wireless mike research will take a bit. Got an urgent matter
from a client, plus the concrete I poured isn't curing as expected. Oh
drat. Anyway, you might want to take a look at what is available in the
new G2 series. They also have sets with transmitter, receivers, mike,
cables and so on all in a kit:

http://www.sennheiser.com/sennheiser/icm_eng.nsf/root/products_wireless-systems_evolution_series100

Meantime I have seen some price specials for G2 sets under $1000 and for
the G2 lapel transmitters under $300 (but that was sans lapel mike). In
the end you'll have to decide how upgradeable/expandable you want it. If
you anticipate several channels are needed some day then you may have no
choice but to go the 19" rack route. That's what we have at church so
far, four rack mount receivers and a 1-4 pair diversity splitter.

Regards, Joerg

http://www.analogconsultants.com

John Perry · Jun 20, 2005

keith wrote:

On Fri, 17 Jun 2005 08:55:21 -0700, John Larkin wrote:

The French like those silly portable air conditioners, the ones with the
hot air dump hose that you stick out the window. They're hardly worth
the effort.

I see those in the stores here. What assinine contraptions! The
condenser in the room is just such a good idea.

Well, at least in Italy where my in-laws lived, there were no other
options short of knocking out a lot of wall. There are very few wooden
houses in southern and central Italy, and the concrete or marble balcony
door and window frames have no places to attach a window unit.

So they buy a two-piece unit, with the compressor to be rolled out onto
the balcony, and the evaporator to be kept inside. High-pressure hoses
conduct the working fluid back and forth, and the units do a very good
job of cooling a room or two or three.

Maybe this isn't the same as the French thing you were talking about?
There were no air hoses involved at all -- the compressor and evaporator
had separate fans. I've never seen anything with an air hose.

John Perry

Ross Herbert · Jun 20, 2005

On Sat, 18 Jun 2005 18:23:05 GMT, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Hello Paul,

That makes sense. If you operate the house at a slight positive
pressure, you have the opportunity to condition (filter, heat and/or
cool) the air introduced. In order to maintain air flow, you'd have to
provide some means for air to escape. Well-sealed houses have a problem
with this. Heat exchanger systems have an outflow duct which takes care
of this, but with a simple blower, you'd have to open a window or have
an exit duct somewhere. Ideally, the exit duct would be equipped with a
damper that would regulate the interior pressure to keep it slightly
positive.

That would be a nice system. The whole house fan seems to reverse it,
creating a pressure drop. Just imagine the horror scenario when the
fireplace is used and a kid flips on the whole house fan switch.

Regards, Joerg

This company appears to have such a system
http://www.cardiffair.com.au/

This site has a Macromedia Flash front end so if you don't have this
installed you will have to wait a few seconds for the tme expiration
before getting access to the non-flash version by hitting the skip
intro link.

Joerg · Jun 20, 2005

Hello Ross,

This company appears to have such a system
http://www.cardiffair.com.au/

This site has a Macromedia Flash front end so if you don't have this
installed you will have to wait a few seconds for the tme expiration
before getting access to the non-flash version by hitting the skip
intro link.

Well, thanks, but I found mostly fluff on the site. The page "How
Cardiffair works!" was blank on Mozilla. When I see Flash and lots of
text along the lines of "ours is the best" but no technical drawings,
somehow that turns me off.

Regards, Joerg

http://www.analogconsultants.com

John Larkin · Jun 21, 2005

On Mon, 20 Jun 2005 01:32:58 -0400, John Perry <jp@no.spam> wrote:

keith wrote:
On Fri, 17 Jun 2005 08:55:21 -0700, John Larkin wrote:

The French like those silly portable air conditioners, the ones with the
hot air dump hose that you stick out the window. They're hardly worth
the effort.

I see those in the stores here. What assinine contraptions! The
condenser in the room is just such a good idea.

Well, at least in Italy where my in-laws lived, there were no other
options short of knocking out a lot of wall. There are very few wooden
houses in southern and central Italy, and the concrete or marble balcony
door and window frames have no places to attach a window unit.

So they buy a two-piece unit, with the compressor to be rolled out onto
the balcony, and the evaporator to be kept inside. High-pressure hoses
conduct the working fluid back and forth, and the units do a very good
job of cooling a room or two or three.

Maybe this isn't the same as the French thing you were talking about?
There were no air hoses involved at all -- the compressor and evaporator
had separate fans. I've never seen anything with an air hose.

John Perry

I meant one of these:

http://www.sylvane.com/delonghi-pac700t.html

You have to vent the hot air out a window through a flexible hose. We
bought one for cooling PC boards, but it won't get much more than 6-8
C below ambient. Useless.

John

Ross Herbert · Jun 21, 2005

On Mon, 20 Jun 2005 17:18:25 GMT, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Hello Ross,

This company appears to have such a system
http://www.cardiffair.com.au/

This site has a Macromedia Flash front end so if you don't have this
installed you will have to wait a few seconds for the tme expiration
before getting access to the non-flash version by hitting the skip
intro link.

Well, thanks, but I found mostly fluff on the site. The page "How
Cardiffair works!" was blank on Mozilla. When I see Flash and lots of
text along the lines of "ours is the best" but no technical drawings,
somehow that turns me off.

Regards, Joerg

http://www.analogconsultants.com

Joerg,

I agree the site is mostly fluff. I emailed the owner complaining
about the use of flash and the lack of relevant technical detail and
it appears that he is also responsible for the website as well as
runing the business.

Here is his reply.

From: "Cardiffair Sales" <sales@cardiffair.com.au>
To: <rherber1@bigpond.net.au>
Subject: RE: Cardiffair: enquiry form submission

Thank you for your e-mail and feedback regarding our site. Our site is
still in its infancy and we do have a lack of photos and pictures. We
have a lot of old ones we could still use but have chosen not to. The
flash has only been installed for our promo and will be switched off
when the promo has finished. I regret that I do have a lot of work to
do and most times can only manage to update after work hours. The
technical information falls in the same category. If you wish for more
information I will do my best to get it to you.

Thanks for your time and feedback on our site,

All at Cardiff Air Control Systems P/L

Frithiof Andreas Jensen · Jun 21, 2005

"Fred Bloggs" <nospam@nospam.com> wrote in message
news:42B2D7BB.5000800@nospam.com...

Most of our whole house fans do draw air from the interior and into the
attic to be blown through the vents, and we do have systems with heat
exchange on exhaust/intake if necessary. Furthermore we are intelligent
enough to have developed ground heat exchangers in colder areas which
seems to be beyond the capability of the Danes.

"We are"??? Really.

"Ground Heat" is a pretty lame system, way overpriced for what the
requirements are - since 'round 'ere 80% of the energy consumption lies at
outdoor temperatures above 5 deg. C. where Air -> Water will work just fine.

But sure, some eco-nutters got those systems in the late 70'ies then public
interest wore out.

Joerg · Jun 21, 2005

Hello Ross,

Thank you for your e-mail and feedback regarding our site. Our site is
still in its infancy and we do have a lack of photos and pictures. We
have a lot of old ones we could still use but have chosen not to. The
flash has only been installed for our promo and will be switched off
when the promo has finished. I regret that I do have a lot of work to
do and most times can only manage to update after work hours. The
technical information falls in the same category. If you wish for more
information I will do my best to get it to you.

Thanks for your time and feedback on our site,

All at Cardiff Air Control Systems P/L

Hmmm, if they don't have the time it might be better not to have a web
site at all. Promo? Sounds more like demo but in the way contractors
refer to that term (demolition) because it certainly turns potential
customers off when there is mostly fluff and no hard data. Like what
kind of fans? What does it cost? How is it going to be installed?
Details, details. I mean, this kind of stuff will initially cater to
technical minds. Engineers. And they want just the facts.

It's like when someone lists prices and all that is stated there is
"call". I never do....

Regards, Joerg

http://www.analogconsultants.com

Ross Herbert · Jun 22, 2005

On Tue, 21 Jun 2005 17:58:09 GMT, Joerg
<notthisjoergsch@removethispacbell.net> wrote:

Hello Ross,

Thank you for your e-mail and feedback regarding our site. Our site is
still in its infancy and we do have a lack of photos and pictures. We
have a lot of old ones we could still use but have chosen not to. The
flash has only been installed for our promo and will be switched off
when the promo has finished. I regret that I do have a lot of work to
do and most times can only manage to update after work hours. The
technical information falls in the same category. If you wish for more
information I will do my best to get it to you.

Thanks for your time and feedback on our site,

All at Cardiff Air Control Systems P/L

Hmmm, if they don't have the time it might be better not to have a web
site at all. Promo? Sounds more like demo but in the way contractors
refer to that term (demolition) because it certainly turns potential
customers off when there is mostly fluff and no hard data. Like what
kind of fans? What does it cost? How is it going to be installed?
Details, details. I mean, this kind of stuff will initially cater to
technical minds. Engineers. And they want just the facts.

It's like when someone lists prices and all that is stated there is
"call". I never do....

Regards, Joerg

I agree with your assessment and I conveyed exactly that sentiment in
my email to the company. Without good technical info nobody is going
to take the trouble to follow up so a website which is meant to
promote a product does the opposite.

I did find a couple of pics on the website which shows the fan is a
large low speed radial intake unit. It seems it can be mounted in a
rooftop mounted enclosure similar to the ones used for conventional
evaporative ducted a/c. Alternatively, provided you have the space, it
seems it can be vertically mounted in a wall but there must be more to
it. If you have a look at PRODUCTS/PHOTO GALLERY/DOMESTIC you can get
some idea, but I agree the paucity of technical info is not conducive
to finding out more.

OT: Whole house ventilation

Charlie Edmondson

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OT: Whole house ventilation

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