James Baber wrote:

...I live in Fresno California, where the temperatures in summer are high...

NREL says Fresno in August is 81.9 F, with an average daily min of 63.8 and
an average humidity ratio w = 0.0092, which makes Pa = 29.921/(1+0.62198/w)
= 0.3461 "Hg, which makes the dew point about 9621/(17.863-ln(Pa)) = 514.7 R
or 54.7 F. Evaporative cooling might help.

The average hourly temperature for each hour for the past 74 days has been
80.5 F, with an average of 96.8 F at 17:00 and an average of 71 F at 08:00...

I concur with Gary about the beneficial effects of a wholehouse fan, but I
cannot run mine 24 hours a day as you could in England.

I doubt that's a good idea in England either. IMO, an attic should be well-
vented, and a WHF should only run when the outdoor temp is cooler, or maybe
a little bit warmer than indoors, with internal electrical usage.

By running mine only when the outside air is cooler than the inside air,
AND only when the inside air is less than 82 F, I have been able to
typically reduce the time I run my air conditioning by 75%.

You might run it when outdoor air is cooler and indoor air is 56% RH,
and turn on an indoor mister when the indoor air is warmer than 82 F.

The wholehouse fan uses 450 Watts / hour...

Just watts. "Watts / hour" is meaningless. I like Grainger's $73 4TM66
3-speed 16" reversible window fan with thermostat, which moves 5850 cfm
with 90 watts on the highest speed.

One major benefit of banking the cooler thermal mass of the house and its
contents until needed in the afternoon is the obvious savings in electrical
energy in kWh.

Doing that well may require 2 fans, one to move outdoor air through the
house and another ceiling fan to mix it around in the house. The outdoor
air won't cool much mass if it just passes through the house in a compact
stream. It's also nice to have moving vs stillish air near the mass
in order to raise the surface airfilm conductance.

Gary might run a WHF in Billings in July, when the daily min temp is 58 F
and the daily max is 87 and w = 0.0080. With a F cfm fan and constant day
and night temps, he might have something like this:

1/F
58/87-----/ ---www----- T RC = 6K/400 = 15 hours, with the fan off.
| |
| 1/400 | 70 = 87+(T-87)e^-(12/15) = 47.91+0.449T
-----www----| makes T = 49.2 F, so it looks like
| he needs a longer time constant
--- 6,000 Btu/F to keep the house 70 F max when
--- it's 87 F outdoors for 12 hours.
|
-

If 2" of concrete floor over hollow blocks adds 32'x32'(5+2/12x25) = 9387
Btu/F and raises RC to 38 hours with the fan off, 70 = 87+(T-87)e^-(12/38)
= 23.3+0.732T, and T = 63.8 F at dawn. If 63.8 = 58+(70-58)e^-(12/RCn),
RCn = -12/ln((63.8-58)/(70-58)) = 16.5 hours = 15387/(400+F), F = 532 cfm.
Not much.

But why waste coolth by keeping the house close to 63.8 F just after dawn?
If the slab is T (F) at dawn and we keep the house air 70 F all day with
a cooling thermostat and a slow ceiling fan (without which cool air will
stay near the floor) and an occupancy sensor, the house will only need
12h(87-70)400 = 81,600 Btu of coolth, max, and 81600 = (70-T)x15387 makes
T = 64.7, so RCn = 20.6 hours and F = 347 cfm, or less, with indoor mist.

...the second major reason is because I am on an Time of Use electrical rate
structure the cost of electricity is much higher /kWh) in the peak
demand period (12:00 - 18:00) vs all the rest of the time /kWh)...

I also use it to warm the house on warm afternoons in the winter instead of
burning gas to heat the house...

Nice, if the outdoor dew point is above the indoor house wall temp,
to avoid condensation...

Nick

wrote in message ...

I like Grainger's $73 4TM66
3-speed 16" reversible window fan with thermostat, which moves 5850 cfm
with 90 watts on the highest speed.

thats way cheap. I've been looking at 9"/12"ers at £100, about 150usd,
and 550cfm.

But more importantly most fans dont seem to have dB ratings, and that
is a real issue considering the fans would be above bedrooms and run
at night, and mounted on a springy PB ceiling.


Doing that well may require 2 fans, one to move outdoor air through the
house and another ceiling fan to mix it around in the house. The outdoor
air won't cool much mass if it just passes through the house in a compact
stream. It's also nice to have moving vs stillish air near the mass
in order to raise the surface airfilm conductance.

Thats my #1 concern here. A WHF will move air through the already
coolest parts of the house, but not through the rooms where cooling is
needed most. Not sure how to address that. Would still be a benefit
though, and much less cost than multiple fans.


Regards, NT

N. Thornton wrote:
wrote in message ...


I like Grainger's $73 4TM66
3-speed 16" reversible window fan with thermostat, which moves 5850 cfm
with 90 watts on the highest speed.


thats way cheap. I've been looking at 9"/12"ers at £100, about 150usd,
and 550cfm.

But more importantly most fans dont seem to have dB ratings, and that
is a real issue considering the fans would be above bedrooms and run
at night, and mounted on a springy PB ceiling.


Our current whole house fan is in the hall ceiling just outside the
bedroom, and we often run it on low speed at night on a timer, set to
turn off around 2am or so. The noise is kind of a low frequency
rumble that is not very loud, and does not keep anyone awake. But, I
suppose this could vary from brand to brand.

The fan is a 30 inches in diameter, and is belt driven through a step
down pulley -- not sure what the final rpm is, but you can see the
individual blades turning on low speed. If you are concerned about
the noise, I would be sure to get one with two (or more) speeds.
I think the price was about $150ish.

Some of the WHFs are fairly awesome on the highest speed -- the one we
had in our last house would pull the drapes in at a 30 deg angle on
several windows :-) -- good for a quick cool down.


Doing that well may require 2 fans, one to move outdoor air through the
house and another ceiling fan to mix it around in the house. The outdoor
air won't cool much mass if it just passes through the house in a compact
stream. It's also nice to have moving vs stillish air near the mass
in order to raise the surface airfilm conductance.




Thats my #1 concern here. A WHF will move air through the already
coolest parts of the house, but not through the rooms where cooling is
needed most. Not sure how to address that. Would still be a benefit
though, and much less cost than multiple fans.

You can control which rooms gets cooled by just opening windows in the
rooms you want cooled. To get the flow balanced the way you want it
between the different rooms, you may have to close the windows in some
of the rooms part way (usually the rooms closest to the fan). Overall
we find it to be a pretty flexible system. Although, if you have a
good place to locate a high capacity window exhaust fan, I don't see
why that shouldn't do the same thing. I think that a good window fan
location would be one that can pull air through other open windows
throughout the house, and in a location where you don't mind a fairly
high velocity of exiting air.

Don't overlook the fact that if you use a WHF, you will have to
provide an exit vent in the attic. Normal attic venting does not
provide enough area.

Regards, NT

In article ,
Gary wrote:

N. Thornton wrote:
wrote in message
...


I like Grainger's $73 4TM66
3-speed 16" reversible window fan with thermostat, which moves 5850 cfm
with 90 watts on the highest speed.


thats way cheap. I've been looking at 9"/12"ers at £100, about 150usd,
and 550cfm.

But more importantly most fans dont seem to have dB ratings, and that
is a real issue considering the fans would be above bedrooms and run
at night, and mounted on a springy PB ceiling.


Our current whole house fan is in the hall ceiling just outside the
bedroom, and we often run it on low speed at night on a timer, set to
turn off around 2am or so. The noise is kind of a low frequency
rumble that is not very loud, and does not keep anyone awake. But, I
suppose this could vary from brand to brand.

The fan is a 30 inches in diameter, and is belt driven through a step
down pulley -- not sure what the final rpm is, but you can see the
individual blades turning on low speed. If you are concerned about
the noise, I would be sure to get one with two (or more) speeds.
I think the price was about $150ish.

Some of the WHFs are fairly awesome on the highest speed -- the one we
had in our last house would pull the drapes in at a 30 deg angle on
several windows :-) -- good for a quick cool down.


Doing that well may require 2 fans, one to move outdoor air through the
house and another ceiling fan to mix it around in the house. The outdoor
air won't cool much mass if it just passes through the house in a compact
stream. It's also nice to have moving vs stillish air near the mass
in order to raise the surface airfilm conductance.




Thats my #1 concern here. A WHF will move air through the already
coolest parts of the house, but not through the rooms where cooling is
needed most. Not sure how to address that. Would still be a benefit
though, and much less cost than multiple fans.

You can control which rooms gets cooled by just opening windows in the
rooms you want cooled. To get the flow balanced the way you want it
between the different rooms, you may have to close the windows in some
of the rooms part way (usually the rooms closest to the fan). Overall
we find it to be a pretty flexible system. Although, if you have a
good place to locate a high capacity window exhaust fan, I don't see
why that shouldn't do the same thing. I think that a good window fan
location would be one that can pull air through other open windows
throughout the house, and in a location where you don't mind a fairly
high velocity of exiting air.

Don't overlook the fact that if you use a WHF, you will have to
provide an exit vent in the attic. Normal attic venting does not
provide enough area.

Regards, NT



Don't know why you'd do this, but you could probably mount a WHF in a
piece of plywood and mount it in the window furthest from your room. Get
the benefit of the fan and it would be quieter. Plus no extra attic
venting.

Gary wrote in message ...
N. Thornton wrote:

Our current whole house fan is in the hall ceiling just outside the
bedroom, and we often run it on low speed at night on a timer, set to
turn off around 2am or so. The noise is kind of a low frequency
rumble that is not very loud, and does not keep anyone awake. But, I
suppose this could vary from brand to brand.

The fan is a 30 inches in diameter, and is belt driven through a step
down pulley -- not sure what the final rpm is, but you can see the
individual blades turning on low speed. If you are concerned about
the noise, I would be sure to get one with two (or more) speeds.
I think the price was about $150ish.

this really confirms my brief thought to use a ceiling fan and make a
thin flexible plywood cowl for it. Mount the fan on the roof rather
than ceiling, with an extended drop rod. This would deal with the
noise issue, provide sufficient air shift, come with 3 speed settings,
and be cheap too.


Some of the WHFs are fairly awesome on the highest speed -- the one we
had in our last house would pull the drapes in at a 30 deg angle on
several windows :-) -- good for a quick cool down.

I bet! I had a 1.4kW one once, wish I still had it. Sadly I dont. It
could turn an oven into a cold wind tunnel in seconds. A bit too much
really.


Thats my #1 concern here. A WHF will move air through the already
coolest parts of the house, but not through the rooms where cooling is
needed most. Not sure how to address that. Would still be a benefit
though, and much less cost than multiple fans.

You can control which rooms gets cooled by just opening windows in the
rooms you want cooled. To get the flow balanced the way you want it
between the different rooms, you may have to close the windows in some
of the rooms part way (usually the rooms closest to the fan). Overall
we find it to be a pretty flexible system.

of course - so simple but I didnt think of it. Thank you. Much of the
air flow will have to negotiate closed doors, but several in parallel
should provide at least some airflow I hope. I'm not real convinced
though.


Although, if you have a
good place to locate a high capacity window exhaust fan, I don't see
why that shouldn't do the same thing. I think that a good window fan
location would be one that can pull air through other open windows
throughout the house, and in a location where you don't mind a fairly
high velocity of exiting air.

I think that would probably be too noisy. Also be more expensive on
wiring (with channelling), and look ugly. In terms of cooling function
it would be almost ideal, but.

Don't overlook the fact that if you use a WHF, you will have to
provide an exit vent in the attic. Normal attic venting does not
provide enough area.

of course. There is no attic venting at present. My bigger concern
though is the doors. There is only a very small area of gap under
each, and ceilng fans are high volume low pressure. This strikes me as
the one last problem. I _dont_ want horrible metal grills in the
doors. Will think some more... perhaps slice a little off the doors.
Thanks.


Regards, NT

N. Thornton wrote:

wrote:

I like Grainger's $73 4TM66 3-speed 16" reversible window fan with
thermostat, which moves 5850 cfm with 90 watts on the highest speed.

thats way cheap. I've been looking at 9"/12"ers at £100, about 150usd,
and 550cfm.

I'm surprised they are so expensive in the UK. Grainger's has a 120 V motor.
You might look for window box fans in some large UK home building supply
store or industrial hardware store, or convert your house to 120 V :-)

...The outdoor air won't cool much mass if it just passes through
the house in a compact stream...

Thats my #1 concern here. A WHF will move air through the already
coolest parts of the house, but not through the rooms where cooling is
needed most. Not sure how to address that...

Put the fan in a window on one side of the house, and open a few house
windows a bit on the other side. Use a cigarette or your velocity stick
and open or close the windows a bit to ensure uniform air velocity or
air temperature in every part of the house with the fan running, eg
through the connecting doors of all rooms?

Nick

N. Thornton wrote:

Gary wrote in message ...

The fan is a 30 inches in diameter, and is belt driven through a step
down pulley -- not sure what the final rpm is, but you can see the
individual blades turning on low speed. If you are concerned about
the noise, I would be sure to get one with two (or more) speeds.
I think the price was about $150ish.

this really confirms my brief thought to use a ceiling fan and make a
thin flexible plywood cowl for it. Mount the fan on the roof rather
than ceiling, with an extended drop rod. This would deal with the
noise issue, provide sufficient air shift, come with 3 speed settings,
and be cheap too.
....

I think you'll find the blades on a ceiling fan aren't shaped to
be very efficient. Most whole house fans, even the window versions,
have a much more advanced shape. You might do better to buy two or
three cheap box fans. Place a curved duct inside the box and they
can pull a lot of air. They usually have three speeds and on "low"
they're pretty quiet. Two or three set on low will be able to pull
a lot of air through your building and you could turn them on/off
individually to act as a kind of multi-speed control.

Anthony

Anthony Matonak wrote in message news:dVkYc.1661$6q.1348@trnddc06...
N. Thornton wrote:

this really confirms my brief thought to use a ceiling fan and make a
thin flexible plywood cowl for it. Mount the fan on the roof rather
than ceiling, with an extended drop rod. This would deal with the
noise issue, provide sufficient air shift, come with 3 speed settings,
and be cheap too.
...

I think you'll find the blades on a ceiling fan aren't shaped to
be very efficient. Most whole house fans, even the window versions,
have a much more advanced shape. You might do better to buy two or
three cheap box fans.

Cheap box fans are thoroughly noisy though. This will be operating
above bedroom ceilings. They are also a fire risk, and will be
operating out of sight or smell. Decent box fans I've been seeing at
90-150 GBP each in trade catalogs, x1.5 to get USD.


Place a curved duct inside the box

ya lost me there

and they
can pull a lot of air. They usually have three speeds and on "low"
they're pretty quiet. Two or three set on low will be able to pull
a lot of air through your building and you could turn them on/off
individually to act as a kind of multi-speed control.

This would work fine with the decent ones, but be about 15 times the
cost of a ceilng fan, 300 rather than 20. If I need to do that, OK,
but do I?


Regards, NT

wrote in message ...
N. Thornton wrote:

I'm surprised they are so expensive in the UK. Grainger's has a 120 V motor.
You might look for window box fans in some large UK home building supply
store or industrial hardware store, or convert your house to 120 V :-)

thats not so hard actually, the 120v. I've no idea what it would cost
to import one, but more significantly our 50Hz tends to roast your
60Hz motors.

The fans in the sheds (stores) are not of acceptable quality, from
either noise or fire risk point of view. Certainly I could buy them at
20 a piece, but theres no point installing something everyone
complains about and wont use, and which is a fire risk. Unfortunately
the decent ones are a lot more money.


Put the fan in a window on one side of the house, and open a few house
windows a bit on the other side. Use a cigarette or your velocity stick
and open or close the windows a bit to ensure uniform air velocity or
air temperature in every part of the house with the fan running, eg
through the connecting doors of all rooms?

Well... have already tried an unfanned version of this, and the
cooperation just isnt there, so it doesnt work. Works great when
people cooperate, but you know what its like...

Seems like every idea theres some kinda block with Oh and the whole
house fan, the only location it could go theres something in the way
that cant be moved! Life :/ The only option this leaves me with that I
can see is one fan per room, with the attic having its own fan and not
connected with the rest of the house. Unfortunately it means a lot of
pricey fans, a lot of holes and a lot of chasing and wiring. I dont
like that.


Regards, NT

for ronnie the christian capon who is afraid of todays date wrote in message news:

Don't know why you'd do this, but you could probably mount a WHF in a
piece of plywood and mount it in the window furthest from your room. Get
the benefit of the fan and it would be quieter. Plus no extra attic
venting.

It would also look like crap and be noisy for whoevers in that room,
so they wouldnt use it.

Attic heat is part of the problem, our attics are unvented here.