Well, my wife concedes that I've already outgrown my gh. Due to that
we live in a city where our neighbor's house is too close, I'm going to
have to build a shed like greenhouse. You know -- where the solid
walls are facing the neighbors and an SE wall and roof will be glazed.
As I was evaluating insulation qualities of commercially available
hobby ghs, I found them lacking in the ability to retain heat, typical
walls had an R factor of less than 5. I was wondering what folks did
to keep from heating the great outdoors while trying to get the most of
the winter sunshine and money in their pocker or least saved for the
next orchid. So I'd like to hear what folks do to better insulate
those glazed surfaces.

Thanks
Mike

PS: Has anyone built their glazed walls with double paned windows?
It's probably only 2 has expensive for about the same or better R value
and it comes already framed. Any ideas there ???????????

Multiwall polycarbonate - the thicker the better.

--

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


"mmccaws" wrote in message
oups.com...
Well, my wife concedes that I've already outgrown my gh. Due to that
we live in a city where our neighbor's house is too close, I'm going to
have to build a shed like greenhouse. You know -- where the solid
walls are facing the neighbors and an SE wall and roof will be glazed.
As I was evaluating insulation qualities of commercially available
hobby ghs, I found them lacking in the ability to retain heat, typical
walls had an R factor of less than 5. I was wondering what folks did
to keep from heating the great outdoors while trying to get the most of
the winter sunshine and money in their pocker or least saved for the
next orchid. So I'd like to hear what folks do to better insulate
those glazed surfaces.

Thanks
Mike

PS: Has anyone built their glazed walls with double paned windows?
It's probably only 2 has expensive for about the same or better R value
and it comes already framed. Any ideas there ???????????

On Tue, 8 Feb 2005 22:40:00 -0500, "Ray"
wrote:

Multiwall polycarbonate - the thicker the better.

Built a window gh out of salvaged thermal panes one time.
But we had an all glass house and just changed the ends to twin
wall. Also insulated the gh door with an add on of twin wall and
a shrink to fit plastic. You know, the stuff renters use as
storm windows. It drastically reduced the heat bill. I would
build of triple if I were building. Also put it 1/2 in the
ground with lots of mass (feet not inches) of rock to hold heat
in the winter and moist cool air in the summer.
SuE
http://orchids.legolas.org/gallery/albums.php

PS: Has anyone built their glazed walls with double paned windows?
It's probably only 2 has expensive for about the same or better R value
and it comes already framed. Any ideas there ???????????

I know somebody who built an entire greenhouse out of Anderson
skylights... Of course he works for a building supply company, so I
presume he got a good deal. Too expensive for the rest of us.

I think the main problem with heavily insulating your glazing is that
it inevitably will decrease your light transmission. Which in turn will
decrease the solar gain you get during the day. Triple wall is probably
as good as you are going to get and still be able to grow plants. If
you really really feel the need for insulating your glazed surfaces,
consider covering the glass only at night. You could throw an
insulating blanket over the top, or rig some system to deploy it when
the sun goes down (like a venetian blind).

Since I'm full of wild ideas lately, let me tell you what I really want
to do with a greenhouse some day. Insulate the heck out of the north
wall, and bury the whole structure a few feet. Glaze it normally
(probably triple wall, since I grow lower light species). Hot water
heat. Here is the kicker, collect thermal energy in a big hot water
tank using some solar collectors. You'd still need a boiler of some
sort, but you could pipe your solar hot water to it. You can get really
good evacuated tube collectors for not much money, they will heat water
even when it is cloudy (not as well, of course). My consultants tell me
this is a 'solar flywheel', like the flywheel on your car it stores and
smooths the release of energy.

Anyway, I've talked to a bunch of solar people about my wild and crazy
schemes, and they all agree that the real way to save money is to
insulate the heck out of the greenhouse. Then and only then is it worth
trying to save more money with fancy technology.

And consider your geography. I don't know where you are, but if you
are in Georgia or Texas, it might get cold for a little while, but you
need to consider how much you are going to spend on insulation and how
much you will save in heating bills. Do the math and see if it makes
sense. Now for me, in the great white north, I need every little bit I
can get. I've already spent over $2000 on propane this year, and I'll
need to fill the tank up again in a few weeks.


Rob
--
Rob's Rules: http://www.msu.edu/~halgren
1) There is always room for one more orchid
2) There is always room for two more orchids
2a) See rule 1
3) When one has insufficient credit to obtain more
orchids, obtain more credit

LittlefrogFarm - Growing the plants Rob likes. )

Thanks Rob and everyone

read below.
Rob Halgren wrote:
PS: Has anyone built their glazed walls with double paned windows?
It's probably only 2 has expensive for about the same or better R
value
and it comes already framed. Any ideas there ???????????

Yeah my goal is to not impact the family budget too much with my hobby.
But technology is always changing. Today solar energy is being
considered an option for the great NW as 10 to 15 years ago they said
you'd be wasting you money. Darn fuel prices always going up.
Technology advance bring once far-flung ideas more affordable.

I know somebody who built an entire greenhouse out of Anderson
skylights... Of course he works for a building supply company, so I
presume he got a good deal. Too expensive for the rest of us.

I think the main problem with heavily insulating your glazing is
that
it inevitably will decrease your light transmission. Which in turn
will
decrease the solar gain you get during the day. Triple wall is
probably
as good as you are going to get and still be able to grow plants. If

you really really feel the need for insulating your glazed surfaces,
consider covering the glass only at night. You could throw an
insulating blanket over the top, or rig some system to deploy it when

the sun goes down (like a venetian blind).

Does anyone do this? Do you use a commercially available product?

Since I'm full of wild ideas lately, let me tell you what I really
want
to do with a greenhouse some day. Insulate the heck out of the north

wall, and bury the whole structure a few feet. Glaze it normally
(probably triple wall, since I grow lower light species). Hot water
heat. Here is the kicker, collect thermal energy in a big hot water
tank using some solar collectors. You'd still need a boiler of some
sort, but you could pipe your solar hot water to it. You can get
really
good evacuated tube collectors for not much money, they will heat
water
even when it is cloudy (not as well, of course). My consultants tell
me
this is a 'solar flywheel', like the flywheel on your car it stores
and
smooths the release of energy.

In early England, when the Romans were there they built stone buildings
with a fireplace sunk into the center of the floor. Then the exhaust
was funneled in stone channels under the floor to the wall and then up
the wall to above the roof. Extremely efficient for the day and age.
I was thinking of mounting solar panels on the south side and roof to
eak out every watt I could then power a water heater and pump of sorts
which would circulate through the floor. Been trying to decide which
would gather more energy, solar photovotaic panel or solar water
heater. One requires insulation the other may require power
conversion.

When I was working with fiber optics I worked with folks on a special
research of using GaAs power cells that are more balanced to capture
energy from a broader spectrum. I always wondered where that research
went. The industry has a tendency to eaak out all they can of SiO
technology before they'll rebuild for another, which is fine -- to a
point. I'm off top now

The other thought was when they talk about air currents in spaces
between windows transferring heat I was wondering how much of a vacuum
must be created to reduce that significantly. I used to make aquariums
out of glass and plexi. It is real easy to make translucent box
windows. Creating a small vacuum isn't too hard. Just at what
atmosphere will there be a real advantage. (this guys got too much time
on his mind)



Anyway, I've talked to a bunch of solar people about my wild and
crazy
schemes, and they all agree that the real way to save money is to
insulate the heck out of the greenhouse. Then and only then is it
worth
trying to save more money with fancy technology.

I'm up in Seattle where there is very little light and it's very low in
the sky. The plus side is the temp delta isn't as great. I've been
thinking that for the roof rafter I might go for a trestle rafter to
create openess and if I need to add an inner glazing surface I'll have
a big air pocket. In the city it's considered an accesory bldg so I
have height limitations. I can't go too deep because my sewer line is
3 to 4 feet below the surface.


And consider your geography. I don't know where you are, but if you

are in Georgia or Texas, it might get cold for a little while, but
you
need to consider how much you are going to spend on insulation and
how
much you will save in heating bills. Do the math and see if it makes

sense. Now for me, in the great white north, I need every little bit
I
can get. I've already spent over $2000 on propane this year, and
I'll
need to fill the tank up again in a few weeks.


Talking about doing the math I saw a web site that showed heating
caluculations using surface Area * Temp delta / R value. Is this
correct eventhough you have two large surface areas of very different R
value, or just an extremely rough back of the envelope calculation only
good to 2 significant digits.

Rob
--
Rob's Rules: http://www.msu.edu/~halgren
1) There is always room for one more orchid
2) There is always room for two more orchids
2a) See rule 1
3) When one has insufficient credit to obtain more
orchids, obtain more credit

LittlefrogFarm - Growing the plants Rob likes. )

"mmccaws" wrote in message roups.com...
So I'd like to hear what folks do to better insulate
those glazed surfaces.

Bubble wrap works wonders.

I built my greenhouse with 8 mm twinwall on a wooden frame. After the
first winter, I did the following:

1. Covered the north wall with "Reflectix" insulation stapled to the
inside of the frame. Reflectix is the brand name of a product that
consists of bubble wrap sandwiched between two layers of foil. By
using it on the north wall, I get light reflected back into the
greenhouse and a layer of dead air between the insulation and the
polycarbonate of the north wall.

2. Covered the east, west, and south walls with clear bubblewrap
pushed against the polycarbonate and stapled to the frame. The only
surface that is exposed polycarbonate is the south facing slope of the
roof. The bubblewrap stays up until about the middle of April, and
then I store it in the shed, because I want the greenhouse to loose
heat more rapidly in the summer.

If you don't have electrical conduit and hanging pots in the way, you
could staple a single sheet of polyethylene across the inside of the
frame instead of using strips of bubblewrap.

3. Added a flap of polyethylene inside the door to make a simple
"airlock."

4. Sealed the exhaust fan and intake shutters with styrofoam and
polyethylene from early December to early February. Once temperatures
in the greenhouse start reaching the low 90s during the day, I remove
the insulation and allow the greenhouse to vent. But I still replace
the styrofoam at night when temperatures are below 40 F.

Next time I build a greenhouse, I'll use triple wall, make a solid,
insulated north wall, and have a long south facing shed roof instead
of a symmetrical roof with gable ends. I will probably be more
careful where I put the electrical conduits, so I can more easily
staple a layer of clear polyethylene inside the frame.

"mmccaws" wrote in message roups.com...
I was thinking of mounting solar panels on the south side and roof to
eak out every watt I could then power a water heater and pump of sorts
which would circulate through the floor.

If you mount solar panels on the roof and walls, won't you block light
from the greenhouse? I suspect that allowing the sun to warm the
greenhouse directly and perhaps using some passive solar
collectors(e.g. black barrels of water) inside, will be much more
efficient than trying to convert sunlight to electricity and then
heating water to heat the greenhouse.

If you have your solar panels off to the side, that's another matter.
Then you would get passive gain from the sun shining on the greenhouse
AND electricity from the solar panels.

Nick

Myrmecodia wrote:
"mmccaws" wrote in message
roups.com...
I was thinking of mounting solar panels on the south side and roof
to
eak out every watt I could then power a water heater and pump of
sorts
which would circulate through the floor.

If you mount solar panels on the roof and walls, won't you block
light
from the greenhouse? I suspect that allowing the sun to warm the
greenhouse directly and perhaps using some passive solar
collectors(e.g. black barrels of water) inside, will be much more
efficient than trying to convert sunlight to electricity and then
heating water to heat the greenhouse.

If you have your solar panels off to the side, that's another matter.

Then you would get passive gain from the sun shining on the
greenhouse
AND electricity from the solar panels.

Nick

it was recommended to paint all non-glazed surfaces with 3 coats of
exterior paint. Any product recommendation or horror stories about
using paints -- I don't paint much and in fact I'm allergic to it so
badly that I'll have to have someone else do that but I have to know
what to expect.

I was thinking to either paint the North wall grey, black body surface
that obsorbs energy during winter months, or lower a black current on
that wall during the winter months.

The gh is going to look like a country shed with two large glazed
surfaces to fit better into the neighborhood. The above solid part of
the roof will be where I can mount the solar panel to help run fans and
such.

Well this is fun. I hope this helps others.

mmccaws wrote:


it was recommended to paint all non-glazed surfaces with 3 coats of
exterior paint. Any product recommendation or horror stories about
using paints -- I don't paint much and in fact I'm allergic to it so
badly that I'll have to have someone else do that but I have to know
what to expect.

You probably want to stay away from oil or enamel based paints. I
think those can bleed organics into the air for years after you apply
them (that may be just a rumor). But I would use a good quality latex
paint. Or get the kid across the street to use it... High gloss is
supposed to be easier to clean, although it is also easier to get dirty.
Use a good primer too, that is more important than three coats of
finish paint.

You can purchase a little packet of additive at the home center which
is designed to be a microbicide. Keeps mildew from growing on your
paint. Cheap, and it does actually work pretty darn well. I used this
in my plant room (Good primer, two coats of gloss white latex paint with
the additive). Nothing ever peeled or grew mildew. The rest of the
basement did...

I was thinking to either paint the North wall grey, black body surface
that obsorbs energy during winter months, or lower a black current on
that wall during the winter months.

I'd suggest white... You are going to need as much light as you can
get, especially in the winter and with a half roof. You can always trap
heat with black water barrels. Since I have a 19 month old child, I've
been going through gallon milk jugs like crazy. I fill them with water
(and a touch of bleach) and put them under the plant benches for thermal
mass. I figure I have room for a few thousand milk jugs, and when I run
out of room I'll stack them. A friend of mine suggested green gallon
wine jugs would collect more heat - if you can't drink that much wine
you can pick them up at the recycling center (milk jugs too).

The gh is going to look like a country shed with two large glazed
surfaces to fit better into the neighborhood. The above solid part of
the roof will be where I can mount the solar panel to help run fans and
such.

Don't forget to insulate the tar out of the solid part of the roof.
You might want to use an insulating board, rather than fiberglass (which
gets waterlogged). Or, since you want to do it right the first time,
find a contractor who installs the spray on foam. That would work
great. Use it everywhere... If you are allergic to paint you
definitely want to contract that out.

All this is making me think I might build my second greenhouse sooner
than planned... *grin* My wife would just love that.

--
Rob's Rules: http://www.msu.edu/~halgren
1) There is always room for one more orchid
2) There is always room for two more orchids
2a) See rule 1
3) When one has insufficient credit to obtain more
orchids, obtain more credit

LittlefrogFarm - Growing the plants Rob likes. )