Been there, done that. :)

Nice to know I was ahead of the curve on *something*, lol. (From the get go I selected a spot that was shaded but had good air circulation.)

Just thinking: Wouldn't temperatures tend to be more stable once there are things in the greenhouse? Air seems to change temperature so much more readily than solid (or liquid) mass does.

Aw shucks,

Did we forget to mention that?

Nah I am sure we said it somewhere on here, I think it was in the very small thread where we talked about the automatic beeswax filled vent openers and the thermostatic attic fans.

You know the thread where it was 20F outside, the sun was shining, the vents were open and it was a nice warm 30F in there.

Maybe I dreamed that thread......

To add a note, do not leave empty plug trays, inserts or flats in the greenhouse in direct sunlight.

Especialy if you have the Plastic humidity cover on the plug trays or flats.

I did have 1300 litres of water in black painted buckets, barrels, and bottles, which by itself was giving me 5-7 degrees of seperation between outside temp, and GH temp This is only with outside temps droping to the 40's.

with the plants added I am getting 10 degrees of seperation at 50 degrees.
But what really blew my mind was that my dedication candle, I was getting an aditional 6 degrees of warmth to the greenhouse.

I am looking forward to some winter temps to sit in it, it is amazing how much one human body can heat up the greenhouse, I wonder what two bodies would do.

Anyhow, I will try to get some pics taken and up tomorrow.
I will see if I can get a pic of it in Amazon mode.

could anyone give me a Hint how to embed photos?

Jimmydo, to insert a pic, upload your image to a webhost like photobucket (www.photobucket.com). Under each pic there is a "tag" line...copy that tag line and put it in your post.

Be careful about picture size...I sometimes have to resize my pics so that they aren't bigger than the screen. It is really annoying to try to read any text on a thread after a too-large pic has been posted.

Mylu (where is Mylu?) has thermostat boxes in his GH...basically little shadehouses for the thermostat...white boxes for shade but with holes for good air circulation.

You mentioned a dedication candle ... sounds like you did have a real ceremony, how nice! Care to share? Now that's something I *didn't* think of.

It is delightful to sit in the greenhouse on a sunny but cold winter day - defintely a win/win situation. While I hadn't thought about the heat a body contributes, I did think about the CO2 it adds. Although I'm the only gardener in the family, other family members frequent the greenhouse and I soon learned to look in the greenhouse when my husband goes "missing" ... he's usually out there reading.

Di

Ohmygosh! I NEVER thought about the effect of sunlight on the placement of the intake vents/exhaust fan thermostat!

My new GH is finished, at least to the point of being sealed, except for the frames we will add around the intake vents and exhaust fan and have rather abandonded it for the present, as we hustle to get our fall yard and field work done while the Sun shines, which it hasn't for much of the past month.

But we do have electricity into the GH, so even when it turns really cold, we can still work inside of it and one of the questions has been the placement of the thermostats.

Now I've been warned about the one for the vents/fan, I'll be sure to mount it in a shaded location, but what about the thermostat for the heater?

My best sense tells me it should be mounted by the north facing door at the opposite end of the GH from the heater, because even with the intake vents and exhaust fan closed for the winter, the roof vents will still release excess heat.

Yes? No?

Good thinking re the heater thermostat, Birdwidow. I did learn that one the hard way last winter. Not really thinking it through, when I rearranged in spring I placed the heater pretty much directly under the roof vent, causing the vent to open wider, which in turn let in more cool air that immediately dropped to the floor, kicking on the heat, and of course the process continues. My heater and auto vent opener were providing each other with job security, LOL.

This year I'll be using a remote thermostat - it's more accurate anyway - and have found a better location for the heater.

polished aluminium is very effective at stoping things from heating up in the sun. (Indeed it has the nice property that of all common materials, it radiates the most and absorbs the least sunlight, iron on the other hand is the opposite, especially when coated in a fine layer of Fe3O4)

Oh man there are so few places to put my poor Temperature probe. The transmitter has a White waterproof box, but then it is water proof, so it does not have air flow.

Most of the Shaded spots are near my water buckets (sucking up heat during the day, and radiating heat during the day)

In the box around my Fan and heater (that answers itself) right there. I think I will need to see a pic of one of Mylu's Boxes and build one just for my temperature probe. LOL

Di:
The Ceremony was basically a Native American Harmony with nature ceremony, used to ask for a bountiful harvest when a new field has been cleared.

gardenstate:

I had much discussion here on where to place my heater and settled on the end wall opposite the door, about 1 ft. off the floor. The opening and closing of the door was the subject of another post with lots of input, so installing the thermostat for the heater next to it seemed logical, but it's good to have someone else concur.

Nathan: If I understood you post, installing the vent/fan thermostat inside an open faced, polished aluminum box would be beneficial?

But where? Facing what direction?

Facing inwards or outwards, doesn't really matter. Same principle as foil backed insulation. It's the reflective cavity that is important.

Putting the sensor in a spot that in the shade is better still. Having air moving past better again.

Nathan:

Ah: so we fabricate not 1, but 2 polished aluminum boxes.

We have a metal brake and mill finish aluminum in small sheets is cheap enough. Now I need to learn what compound to use to polish it.

Any suggestions?

Stick your sensor in a polished metal box with good sized air vents to allow the heat to pass through. Althernatively, stick it in small foam box. No need to do anything fancy. Having a box is good to protect from accidental damage. A tiny computer fan might be a good way to keep the air moving past the sensor. Air movement is more significant with humidity sensors than temperature sensors.

My thermostat is mounted on the west wall.I took a small cardboard box,spray painted it white,and mounted it over the thermostat to keep the sunlight off of it.I cut off the northside,amd the bottom of the box.The thermostat fuctions correctly.Mark