[quote]R2 as we know it in America is quite low for house insulation. I used that number to allow for our test greenhouse to have 6mm twinwall on the south and south roof and some insulation on the North walls etc.[/quote] Heh, perhaps I'm just weird then, but I have metric R2 on my north wall (+parts of east and west, +underground) and about metric R 1.4 for the glazing. Metric R values are about 0.17 times US R values. [quote]I am sorry but many here with small greenhouses are infact coming as close to an hermetically sealed structure as possible. 10-20 tubes of calking... on a 6x8ft? [/quote] Well, it depends on what the caulk is being used for. I caulked my insulation on. Let me tell you, that takes a lot of caulk. Even if you seal up all of the cracks, I would be surprised if the small amount of circulation couldn't occur through things like: * The drainage system * Between panes of closed vents * Through the zipper or doorframe. Sure, a vent is a good idea. But we're talking about needing a very small amount of air indeed. [quote]Also in this thread nobody has mentioned the water. Unvented heater, sealed up as best you can, no air exchange. Adding CO2 by burning propane makes it wet in there too.[/quote] That is true. The moisture beads on the glazing and runs down to the floor; it's like a jungle in there (when I wear glasses, it's instant fogging when I walk in). I haven't grown any plants that are sensitive to moisture-related diseases before, but I've got some in the seedling stage right now, so we'll see if they complain. They're doing quite beautifully so far (I could get pictures if you like), but moisture-loving diseases like powdery mildew take some time to get established. I'll get back to you about them in a month or so and let you know how they compare to the equivalent plants grown outside this summer. [quote]stressbaby, Gladly. Greenhouse cucumber operation in Calif. with newly installed unvented heaters. After a cold winter period, severe damage was noted on the crop. Air samples analyzed showed elevated levels of ethylene and mercaptan.[/quote] Elevated *mercaptan* levels? Wow, that heater must have been doing an awful job. Mercaptans are only in PPM quantities to begin with, so if you're having measurable amounts *after* combustion, something is seriously wrong there. [quote]economic losses to greenhouse growers from ethylene pollution are reported each year[/quote] You do realize, I presume, that ethylene pollution can happen even when no heater is used. Decaying plant matter is an especially bad ethylene producer, but even healthy plants produce it (some species more than others). [quote]For an interesting thread from about a year ago, complete with more examples of problems with unvented heaters, use the search function, type "carbon dioxide" and read the posts on "plants suffering from propane". Some noted problems in other "real-life" situations.[/quote] Well, for your information, with Thanksgiving dinner, my main course was a delicious vegetarian lasagne made with a heaping handful of basil from my "suffering" greenhouse basil plants. Last night for dinner, I had pasta primavera made using some of my "suffering" tomatoes. My point? A proper installation doesn't have problems. An improper installation does. Notice how you haven't gotten into the risks of the other common hobby greenhouse heating system, electric. You know, a box of resistors with large amounts of current flowing through it, in a moist environment that usually has a metal frame, and plenty of combustables within, possibly even standing water? I read the "suffering from propane" thread before I got my heater. I read enough from elsewhere to realize that this person had an improper installation. Notice -- it only took a few days of use of their heater for problems to occur. Mine has been running for two months this winter. Note what was mentioned in the thread: "Sometimes the smell is very strong." Huge red flag right there. Properly combusted propane/natural gas has no smell. The instant they smelled it, they should have disconnected the heater -- it sounds like a leak. Note what others said in the comments trail, such as Orchiddude and trigger_m (who also provided pictures). [quote]One factor missed in this thread was ethylene.[/quote] Ethylene was already mentioned several times in this thread. Use your browser's search function; you'll find it.

I forgot to answer david52's question regarding claims. No claims. Ever. Along the lines of answering my own question, I checked out the Rocky Mountain Farmers Union to see if they offer policies, and it seems they do. We will contact this guy in Cortez that I've linked to below (in case anyone else is having the same issues). I can't figure out why all the insurance companies are so eager to write a policy for cars - which kill 10's of thousands of American every year - and yet be so squeemish regarding the source of their sustenance (assuming insurance underwriters actually consume food directly; not just second hand through blood). Anyway, I digress. The link: Here is a link that might be useful: Farmers Union insurance link

That's so sad. It seems that MoMo's case was complicated by the heart failure, which--if it does similar things to both cats and humans (think swollen ankles)--may have caused more fluids than normal in her body, anyway. At least, so I assume, because the subQ fluids were always rapidly absorbed in the case of my last two cats, who surprised the vet by living 'way beyond what he had expected, thanks to Ubiquinol (a more easily absorbed form of CoQ10) and my giving them gradually more frequent treatments with subQ Ringer's solution. They always absorbed the subQ fluids rather quickly after the fluids had a brief stay in the cat's belly, having run down under the skin and accumulated making something like a little flabby pouch in the loose skin there. Considering the fact that MoMo had heart failure on top of CKD, she probably had little time left with you no matter what treatment she received, and you did everything you could in your power to save her. Please don't blame yourself, but dwell instead on the happy life she had with you. It is natural to have regrets after a loved one dies, and I, too, have wished in the cases of a few other pets that I had tried some other things, but I have decided that we need to give ourselves peace as we remember them. Surely they would not wish any added pain on their beloved owners. It's good that you still have some pets to love.

Breenthumb - we used to get those calls too. You are right, they never even tried to tell us they could beat the cost for coverage. My only isse with them is that they wouldn't sell coverage for our DS and DILs house. They bought it in 05, the year after the 4 hurricanes came through central Florida within a month or so of each other. With so many retired military in this area, they stopped new policies on homeowners. We were shocked to hear this but so many insurance companies did the same thing. Anyone who is former military or a dependent of a military can get coverage. Not sure how it works if parent did not have their insurance but its worth checking. Customer service is exemplary!