To ventilate or not?
 

What do other orchid growers do ?Do you shut up the greenhouse and use fans
internally 24/7.This is what i do ,but i am thinking of installing (adding
to this) two 100cm round core vents at low level at each end of the
greenhouse grilled on each side so they will be permanently open to
introduce fresh are.Now i am thinking will this be beneficial and will it
effect heating costs/heat loss .
Thanks Keith

To ventilate or not?
 

I find that no matter how "tight" you think the GH is, there is enough
leakage to keep fresh air exchange going, so adding all-the-time vents is a
waste.

Don't forget: nature hates a gradient. If the air chemistry changes
inside, Mother Nature will remedy that insult.

--

Ray Barkalow - First Rays Orchids - www.firstrays.com
Plants, Supplies. Books, Artwork, and lots of Free Info!


"keith kent" wrote in message
...
What do other orchid growers do ?Do you shut up the greenhouse and use
fans internally 24/7.This is what i do ,but i am thinking of installing
(adding to this) two 100cm round core vents at low level at each end of
the greenhouse grilled on each side so they will be permanently open to
introduce fresh are.Now i am thinking will this be beneficial and will it
effect heating costs/heat loss .
Thanks Keith

To ventilate or not?
 

On Dec 5, 6:46 pm, "keith kent" wrote:
What do other orchid growers do ?Do you shut up the greenhouse and use fans
internally 24/7.This is what i do ,but i am thinking of installing (adding
to this) two 100cm round core vents at low level at each end of the
greenhouse grilled on each side so they will be permanently open to
introduce fresh are.Now i am thinking will this be beneficial and will it
effect heating costs/heat loss .
Thanks Keith

I agree with Ray. (not that it matters but I frequently do) It would
be hard to suffocate in there. I estimate all the cracks and crevices
in my greenhouse are already equal to a square foot opening, ...at
least... and this does not include the vent flews/flues/flooze for the
heaters. I would have to have a hole in my head (its actually pretty
windy in there too) to actually add more holes to the greenhouse.

You can calculate a good guess as to how often the volume of air in
your greenhouse changes by calculating the air infiltration rate.
The air infiltration rate is one part of the calculation for BTU
requirements. Air infiltration and is based on the size and
construction material of the structure , among other less tangible
things like wind speed....
http://aggie-horticulture.tamu.edu/G...hdbk/heat.html
(See item #7 in the calculation)

To ventilate or not?
 

Al,

I got around the heater-related issues by buying a separated-combustion
heater.

Combustion air is drawn in via a 3" flue from the outside. That actually
runs inside of the 6" exhaust flue, which is sealed through the back GH
wall. The cold, outside air is preheated by the exhaust, which increases
fuel combustion efficiency.

All of the controls and the burner are in a sealed volume, so I don't suck
the heat or humidity out!

But then there's the door....

--

Ray Barkalow - First Rays Orchids - www.firstrays.com
Plants, Supplies. Books, Artwork, and lots of Free Info!


"alpickrel" wrote in message
...
On Dec 5, 6:46 pm, "keith kent" wrote:
What do other orchid growers do ?Do you shut up the greenhouse and use
fans
internally 24/7.This is what i do ,but i am thinking of installing
(adding
to this) two 100cm round core vents at low level at each end of the
greenhouse grilled on each side so they will be permanently open to
introduce fresh are.Now i am thinking will this be beneficial and will it
effect heating costs/heat loss .
Thanks Keith

I agree with Ray. (not that it matters but I frequently do) It would
be hard to suffocate in there. I estimate all the cracks and crevices
in my greenhouse are already equal to a square foot opening, ...at
least... and this does not include the vent flews/flues/flooze for the
heaters. I would have to have a hole in my head (its actually pretty
windy in there too) to actually add more holes to the greenhouse.

You can calculate a good guess as to how often the volume of air in
your greenhouse changes by calculating the air infiltration rate.
The air infiltration rate is one part of the calculation for BTU
requirements. Air infiltration and is based on the size and
construction material of the structure , among other less tangible
things like wind speed....
http://aggie-horticulture.tamu.edu/G...hdbk/heat.html
(See item #7 in the calculation)

To ventilate or not?
 

Yikes! Interesting? Thanks for bringing this topic up Keith, I have Southern
Burners with
chimneys & a 2" air intake hole down under & 2 vents open. Seems like I am
wasting energy no?
I do have a up high that runs 24/7 to circulate the warm air but I was under
the impression
that there had to be incoming fresh air all the time.
Going to investigate.
Cheers Wendy

"alpickrel" wrote in message
...
On Dec 5, 6:46 pm, "keith kent" wrote:
What do other orchid growers do ?Do you shut up the greenhouse and use
fans
internally 24/7.This is what i do ,but i am thinking of installing
(adding
to this) two 100cm round core vents at low level at each end of the
greenhouse grilled on each side so they will be permanently open to
introduce fresh are.Now i am thinking will this be beneficial and will it
effect heating costs/heat loss .
Thanks Keith

I agree with Ray. (not that it matters but I frequently do) It would
be hard to suffocate in there. I estimate all the cracks and crevices
in my greenhouse are already equal to a square foot opening, ...at
least... and this does not include the vent flews/flues/flooze for the
heaters. I would have to have a hole in my head (its actually pretty
windy in there too) to actually add more holes to the greenhouse.

You can calculate a good guess as to how often the volume of air in
your greenhouse changes by calculating the air infiltration rate.
The air infiltration rate is one part of the calculation for BTU
requirements. Air infiltration and is based on the size and
construction material of the structure , among other less tangible
things like wind speed....
http://aggie-horticulture.tamu.edu/G...hdbk/heat.html
(See item #7 in the calculation)

To ventilate or not?
 

I have two 3 kw electric heaters so the two vents i am talking about are not
for this purpose,just for added ventilation to keep the air bouyant.My
greenhouse is pretty tight, its new and made from concrete block low walls
and solid wood draught proof double doors at one end and a 25mm
polycarbonate roof.It is probably too insulated as on a frosty day the
polycarb roof gets frosted on the outside and maintaining my 50 f inside !
Condensation can get bad though on the inside roof,so was thinking of
putting the two vents near the heater so the fan on them is drawing in fresh
air all the time .
So still undecided?
Keith
"Wendy7" wrote in message
...
Yikes! Interesting? Thanks for bringing this topic up Keith, I have
Southern Burners with
chimneys & a 2" air intake hole down under & 2 vents open. Seems like I am
wasting energy no?
I do have a up high that runs 24/7 to circulate the warm air but I was
under the impression
that there had to be incoming fresh air all the time.
Going to investigate.
Cheers Wendy

"alpickrel" wrote in message
...
On Dec 5, 6:46 pm, "keith kent" wrote:
What do other orchid growers do ?Do you shut up the greenhouse and use
fans
internally 24/7.This is what i do ,but i am thinking of installing
(adding
to this) two 100cm round core vents at low level at each end of the
greenhouse grilled on each side so they will be permanently open to
introduce fresh are.Now i am thinking will this be beneficial and will
it
effect heating costs/heat loss .
Thanks Keith

I agree with Ray. (not that it matters but I frequently do) It would
be hard to suffocate in there. I estimate all the cracks and crevices
in my greenhouse are already equal to a square foot opening, ...at
least... and this does not include the vent flews/flues/flooze for the
heaters. I would have to have a hole in my head (its actually pretty
windy in there too) to actually add more holes to the greenhouse.

You can calculate a good guess as to how often the volume of air in
your greenhouse changes by calculating the air infiltration rate.
The air infiltration rate is one part of the calculation for BTU
requirements. Air infiltration and is based on the size and
construction material of the structure , among other less tangible
things like wind speed....
http://aggie-horticulture.tamu.edu/G...hdbk/heat.html
(See item #7 in the calculation)

To ventilate or not?
 

I have sheets to cover the most tender plants if the temperature is supposed
to go into the 45 degree range, which would normally last for about 15
minutes.....Don't generally worry about vents.

Sorry, couldn't resist!

Diana

"keith kent" wrote in message
...
I have two 3 kw electric heaters so the two vents i am talking about are
not for this purpose,just for added ventilation to keep the air bouyant.My
greenhouse is pretty tight, its new and made from concrete block low walls
and solid wood draught proof double doors at one end and a 25mm
polycarbonate roof.It is probably too insulated as on a frosty day the
polycarb roof gets frosted on the outside and maintaining my 50 f inside !
Condensation can get bad though on the inside roof,so was thinking of
putting the two vents near the heater so the fan on them is drawing in
fresh air all the time .
So still undecided?
Keith
"Wendy7" wrote in message
...
Yikes! Interesting? Thanks for bringing this topic up Keith, I have
Southern Burners with
chimneys & a 2" air intake hole down under & 2 vents open. Seems like I
am wasting energy no?
I do have a up high that runs 24/7 to circulate the warm air but I was
under the impression
that there had to be incoming fresh air all the time.
Going to investigate.
Cheers Wendy

"alpickrel" wrote in message
...
On Dec 5, 6:46 pm, "keith kent" wrote:
What do other orchid growers do ?Do you shut up the greenhouse and use
fans
internally 24/7.This is what i do ,but i am thinking of installing
(adding
to this) two 100cm round core vents at low level at each end of the
greenhouse grilled on each side so they will be permanently open to
introduce fresh are.Now i am thinking will this be beneficial and will
it
effect heating costs/heat loss .
Thanks Keith

I agree with Ray. (not that it matters but I frequently do) It would
be hard to suffocate in there. I estimate all the cracks and crevices
in my greenhouse are already equal to a square foot opening, ...at
least... and this does not include the vent flews/flues/flooze for the
heaters. I would have to have a hole in my head (its actually pretty
windy in there too) to actually add more holes to the greenhouse.

You can calculate a good guess as to how often the volume of air in
your greenhouse changes by calculating the air infiltration rate.
The air infiltration rate is one part of the calculation for BTU
requirements. Air infiltration and is based on the size and
construction material of the structure , among other less tangible
things like wind speed....
http://aggie-horticulture.tamu.edu/G...hdbk/heat.html
(See item #7 in the calculation)

To ventilate or not?
 

That is a "fan" that runs 24/7 *G*

"Wendy7" wrote in message
...
Yikes! Interesting? Thanks for bringing this topic up Keith, I have
Southern Burners with
chimneys & a 2" air intake hole down under & 2 vents open. Seems like I am
wasting energy no?
I do have a up high that runs 24/7 to circulate the warm air but I was
under the impression
that there had to be incoming fresh air all the time.
Going to investigate.
Cheers Wendy

"alpickrel" wrote in message
...
On Dec 5, 6:46 pm, "keith kent" wrote:
What do other orchid growers do ?Do you shut up the greenhouse and use
fans
internally 24/7.This is what i do ,but i am thinking of installing
(adding
to this) two 100cm round core vents at low level at each end of the
greenhouse grilled on each side so they will be permanently open to
introduce fresh are.Now i am thinking will this be beneficial and will
it
effect heating costs/heat loss .
Thanks Keith

I agree with Ray. (not that it matters but I frequently do) It would
be hard to suffocate in there. I estimate all the cracks and crevices
in my greenhouse are already equal to a square foot opening, ...at
least... and this does not include the vent flews/flues/flooze for the
heaters. I would have to have a hole in my head (its actually pretty
windy in there too) to actually add more holes to the greenhouse.

You can calculate a good guess as to how often the volume of air in
your greenhouse changes by calculating the air infiltration rate.
The air infiltration rate is one part of the calculation for BTU
requirements. Air infiltration and is based on the size and
construction material of the structure , among other less tangible
things like wind speed....
http://aggie-horticulture.tamu.edu/G...hdbk/heat.html
(See item #7 in the calculation)

To ventilate or not?
 

Tenman & Wendy -

Don't worry, I can take a good hurricane jab! The Keys really are
problematic. I love it down there, but it's an impossible situation if
there's a storm.

Anyway, for the most part we are quite secure, even in the face of a
hurricane. There are some middle aged buildings that do not fare so well.
Oddly, the "old Florida" houses stand up very nicely. I'm only guessing, but
I think it's because they were built with the knowledge that a storm could
hit, so the owners fortified them. The newer homes (ours fits into that
description) are pretty safe, provided you take normal precautions. But for
many years, most of FL didn't see a storm of any magnitude. Combine that
with lax building codes in the 60's and you have a recipe for disaster.

As for the orchids, we have a system to close off the patio. It takes some
hauling, but they all go in there. I guess there's not much you can do to
prepare for a quake out in CA, though.

Having said all that, if we ever hear that there is a Cat 4 or 5 on its way,
we'll be at your house, along with Casper the Wonder Cat, LOL!

Diana
"Wendy7" wrote in message
...
That is a "fan" that runs 24/7 *G*

"Wendy7" wrote in message
...
Yikes! Interesting? Thanks for bringing this topic up Keith, I have
Southern Burners with
chimneys & a 2" air intake hole down under & 2 vents open. Seems like I
am wasting energy no?
I do have a up high that runs 24/7 to circulate the warm air but I was
under the impression
that there had to be incoming fresh air all the time.
Going to investigate.
Cheers Wendy

"alpickrel" wrote in message
...
On Dec 5, 6:46 pm, "keith kent" wrote:
What do other orchid growers do ?Do you shut up the greenhouse and use
fans
internally 24/7.This is what i do ,but i am thinking of installing
(adding
to this) two 100cm round core vents at low level at each end of the
greenhouse grilled on each side so they will be permanently open to
introduce fresh are.Now i am thinking will this be beneficial and will
it
effect heating costs/heat loss .
Thanks Keith

I agree with Ray. (not that it matters but I frequently do) It would
be hard to suffocate in there. I estimate all the cracks and crevices
in my greenhouse are already equal to a square foot opening, ...at
least... and this does not include the vent flews/flues/flooze for the
heaters. I would have to have a hole in my head (its actually pretty
windy in there too) to actually add more holes to the greenhouse.

You can calculate a good guess as to how often the volume of air in
your greenhouse changes by calculating the air infiltration rate.
The air infiltration rate is one part of the calculation for BTU
requirements. Air infiltration and is based on the size and
construction material of the structure , among other less tangible
things like wind speed....
http://aggie-horticulture.tamu.edu/G...hdbk/heat.html
(See item #7 in the calculation)