We got everything put back together again yesterday, and the panels all screwed in place to the frame, so there's no moving them now. They're much more solid, even with just a few screws per panel...it's really amazing how well that works! One of the window vents is like greenhouser's now though...very much "stuck" in place (our frame got bent a bit with all the panels being torn out, and there's just no way to straighten it now). The other roof vent is so loose I have to keep it on with clamps. So rather than deal with those vents, I think we're just going to keep them shut for the most part, and I'll buy some auto-vents to put in the top front panel above the door, and the bottom of the far-back panel, and I'll use the fans for exhaust (I saw some in the Charlie's catalog that aren't all that expensive). I won't be using the greenhouse when it's super-hot out anyways (everything should be out of there by the middle of June), so it shouldn't be too much of a problem. I can open the looser vent by hand if need be in May, but taking the insulation down at that time will probably help too. We also got a thermometer with a remote sensor this weekend, and set up the sensor in the greenhouse so we can start monitoring "normal" temperatures. It's pretty cool being able to tell the temperature in the greenhouse from my kitchen, and already this morning by 8am it was warmer than the outside temps by 4 degrees - on an overcast, snowy day (27 deg. outside, 34 in the greenhouse). A fun & useful gadget, to be sure, and we have no problem getting the remote signal in the house. We found an oil-filled electric heater this weekend as well...it was $40, but we figured the extra safety of not having semi-exposed heating coils or electrical was worth the cost. It has three levels, so I'll run it on the middle one (it will run more often, but not pull as much power), and it will work with a 14 gauge extension cord, so we'll get a 10 gauge for "extra" and it should be fine. The internal thermostat should be easy to set (same type as the one in my office). We picked up pavers from my MIL's house she didn't need anymore to create a solid base for the heater to sit on out there. I'm thinking of using foam insulation paneling all the way around the bottom of the walls about 1.5 ft. up (starting in the fountation), since bubble wrap is more expensive, and I won't be growing things that low anyways. Then I'll insulate the rest of the walls and the roof with bubble wrap, and hang a sheet of plastic inside the door. I'll get all that next Saturday, along with benches, fans, and a garden "sink" (that hooks up to a hose). Slowly but surely...all the seeds I planted this weekend should have a good home to grow out in by next Monday.

Harbor Freight did not suggest this. Lets just say that Harbor Freights Tech support was, um Harbor Freight... I have to admit it was nice, they Cross shipped me new ones, which performed the same as the old ones. I found an overseas manufacturer of similar "budget vents", I think they were called Thermofor, who was very helpfull, and gave me a suggestion. I unscrewed the endcap that has the adjustment screw, and press the plunger till the seal almost comes out, then the oil will start to leak if you press softly on the plunger (If I pressed hard the seal comes all the way out, and you get a big mess ;) then close the whole thing and test. THrough trial and error, I now have all five of my HF openers opening between 65 and 75 degrees. Gato, I am not sure why mine did not work, and yours did, I am only 1300 feet higher than you, but I had a Total of ten from HF (The first five and the second five). Even at 38 degrees they were open five inches under load before I modified them ;) I would not recomend that anyone else try this, because I am sure it voids the warranty. (I tried it on just one first, then got bolder and tried the rest. I did spill all the oil out of one, and I replaced the oil with Cooking oil, even this one is now working ;) so I guess I will have to wait and see if opening them is gonna cause any long term ill effects.

burt4750, I have a HFGH but have not installed automatic openers. I do recall when we first built the greenhouse (over six years ago) I had to fiddle quite a bit with the vent windows to make sure they worked smoothly in the openings. There is quite a bit of flex in the Harbor Freight frame, and I recall having to loosen some of the bolts around the window frames, then "wiggling" things around until the windows fit better. Not a very scientific sounding solution, but it might be enough to resolve a slight drag along the edges. So far I've not come across anyone whose Harbor Freight roof windows were manufactured to an incorrectly large size for the openings, so I'm kinda suspecting it's just that the flexible frame needs to be "wiggled and tweaked" to make sure the windows fall into place more easily. Perhaps, worth a try? Here is a link that might be useful: Building our Harbor Freight 10x12 Greenhouse This post was edited by mudhouse on Mon, Nov 4, 13 at 21:09

From Nick Pine (via usenet): Article 63609 of misc.consumers.frugal-living: From: nick@ufo.ee.vill.edu (Nick Pine) Newsgroups: alt.energy.renewable,sci.engr.heat-vent-ac Subject: Re: Refrigerator -keep it full? Date: 2 May 1997 08:26:06 -0400 Organization: Villanova University Mark A. Yedinak wrote: >Polar wrote: >> I'd always heard that refrigerators should be kept full to >> work at maximum efficiency. If the door is closed, full or empty won't make much difference. If the door is opened once in a while, empty seems better, because the greater the surface area inside the refrigerator (eg the more stuff inside) the more heat will transfer to those cold surfaces from warm room air that circulates around them when the door is open. This is known as "Newton's law of cooling," invented by Isaac Newton, who also brought us gravity and calculus :-) >> An engineer friend has just debunked this theory as follows: >> >> He says the basis for the "theory" was that keeping refrig. >> full decreased the volume of air which might escape when door opened. >> The warm air entering, would then have to be cooled. It seems to me that as long as the door is open, room air circulates through the fridge, all the while warming the contents, if any. It's not like a single slug of room air replaces a single slug of refrigerator air, and then airflow stops. A 6' tall fridge might have 16.6x2ft^2sqrt(6'(70F-40F)) = 500 cubic feet per minute of air flowing through it when the door is open. If the door is open for 10 seconds, 80 ft^3 of air might flow through the fridge. Suppose an EMPTY 3' cubical fridge contains 27 ft^3 of space and 54 ft^2 of wall area, and it's 30 F inside and the door is open 10 seconds, allowing 70 F room air to circulate through the fridge. Suppose when the door closes, all the air in the fridge is 70 F and it needs to be cooled to 30 F again. Since 1 Btu can cool about 55 ft^3 of air 1 F, cooling that mass of air requires 27(70F-30F)/55 = 19.6 Btu (0.006 kWh.) But while the door was open, the circulating air heated the 54 ft^2 of interior surface (slightly) with a thermal conductance of about 1.5 Btu/h-F-ft^2, by about 10/3600(70-30)54x1.5 = 9 Btu. So opening the door added about 29 Btu to the empty fridge. Now suppose we FILL the fridge with 216 2 liter soda bottles (each about 12" tall x 4" diameter, with about 1.2 ft^2 of surface area) in 3 layers of 72 bottles, in a nice regular array, with air free to circulate around them, and open the door for 10 seconds. When the door closes, we now only have to cool 27 ft^3 - 216x2/28.32 = 11.75 ft^3 of air, which requires only 8.5 Btu, but while the door was open, we heated 54 + 216x1.2 = 313 ft^2 of surface by 10/3600(70-30)313x1.5 = 52 Btu, adding a total of about 60 Btu to the fridge, twice as much heat. (And perhaps more importantly, we also condensed a lot more water vapor onto that greater surface, at 1000 Btu/lb. The vegetables inside may also have cooled themselves by evaporating more water, which dripped out through the bottom of the fridge and evaporated into the room.) >> ...the energy expended to cool the water bottles, or whatever, is much >>greater than than which would be expended to cool the air entering a >>near-empty frig. True, but that's like comparing apples and oranges, or non-recurring and recurring costs, and it's related to that old myth that setback thermostats don't save money. We only need to spend the energy to cool the thermal mass of the water once, not every time the door is opened. >Your engineer friend is incorrect. The reason a refridgerator runs more >efficiently when full than when empty... Does it? It might, if the compressor cycles less. But years ago (ca 1930), when people cared more about energy efficiency (and today, in Sunfrosts), refrigerators used to have "heat accumulators," thermal mass on the outside of the fridge, attached to the hot coils on the back, to allow them to stay warm even when the compressor was not running, so they could more efficiently transfer heat to the room on a full time vs a part time basis, keeping the hot coils cooler (while making hot water?) I guess empty fridges tend to cycle more often, ie work more in this way. >is because the refridgerator itself is not required to work as much. A full fridge has to work harder at first to cool the contents, but after that, things are about the same. That initial cost is a lot less than the recurring cost, over a few days or more. >When an empty refridgerator is opened and then shut again, the warmer air >which entered needs to be cooled again. The only thing which will be able >to do this is the fridge itself. Agreed, but the objects the warm air warmed while the fridge was open also need to be cooled (and dried) again. The fewer things inside, the less of that cooling is required. >...when the fridge is full, those items take longer to warm, therefore they >stay cool even after the fridge has been opened and closed. These items now >help in cooling the air around them. Agreed, but that doesn't seem relevant to this kind of energy consumption (vs. "thermal mass refrigerators" powered by outdoor coolth, eg in Earthships.) >So, try to keep the fridge full. It will run more efficiently because it >will need to run less. So, try to keep the fridge empty. It will run more efficiently because it will need to run less. Nick It's a snap to save energy in this country. As soon as more people become involved in the basic math of heat transfer and get a gut-level, as well as intellectual, grasp on how a house works, solution after solution will appear. Tom Smith