Saturday, October 23, 2010

Vented vs. Ventless - What Do YOU Use?


As many of you know, a conservatory is being constructed here at Our Little Acre. It started out being called a greenhouse, but since technically a greenhouse is all glass or polycarbonate or some-other-clear-material, what we have going up here isn't a greenhouse. It's a conservatory, which is a room with a lot of windows that allows enough light in to allow plants to grow well.

Construction was begun while Mom and I were in Dallas for the Garden Writers' Association annual symposium at the beginning of September. It required that I move quite a few plants, which wasn't an advisable thing to do when we were in the middle of a drought and experiencing above normal temperatures, but you do what you have to do. At this point, it looks like all have survived except for a tree peony. :-(

In the matter of six weeks, we have gone from this...


...to this...


Which brings us to this point: Which kind of propane heater is the best to use for heating the conservatory? I want to keep it at 60° F or a little higher for the winter. We're in Zone 5b, so our average lowest temperature in winter is -10 to -15 degrees F. The building is 10' x 12' with an open ceiling height at the peak of approximately 10 feet. It will be insulated on all four walls and the ceiling with R-19 fiberglass insulation.

So...which is best? Vented or ventless? My issue with ventless is the automatic safety shut-off when the O2 level reaches critically low levels. Good for humans. Bad for plants that you don't want to freeze. If I have to have a source of fresh O2 so that the ventless heater doesn't shut off anyway, then wouldn't vented be the way to go? And what about blue flame vs. radiant? Any thoughts on that?

The propane tank was set in on Friday and now we just need a heater to attach to it.


What I'd love is for greenhouse owners, greenhouse sellers and anyone who has any experience with either or both of these type heaters to weigh in here so we can make a decision about this. I'm counting on the rest of the gardening world coming through for me with their sage advice! Have at it! I'm all ears!

6 comments:

fer said...

Congrats on the new project completed! It looks great, I wish I had a conservatory of my own.

Rachael said...

We built our greenhouse between the fall of '06 and spring of '07. It's 15 x 20 twinwall polycarbonate and partially sunk into the ground. We use radiant heat. Because we grow orchids, the humidity is rather high,and we were concerned about the shortened lifespan of a standard unit that would actually be in the greenhouse. So, the boiler is in the basement of our house and pipes run underground out to the greenhouse to two runs of baseboard radiators. It keeps the greenhouse nice and toasty during the winter (zone 6b). It is propane fired and runs off of the existing 500 gal. propane tank that the house uses for heat/hot water. I posted some pictures of its construction on facebook last week. My husband designed it and we built it with a lot of help from my father and father in law. I hope I get the link right- I haven't tried to link to FB before. http://www.facebook.com/album.php?aid=255367&id=789632471

Nutty Gnome said...

Afraid I can offer no advice on conservatory heating but I'm full of admiration for how good the building is looking - and just a tad envious too!

thewritegardener said...

It looks great Ms. Kylee! I bet you'll love it when all things are in place! Wish I could help you with the technical details you asked about, but I can't.

joey said...

You lucky gal, Kylee! Wish I could help but, in the meantime, happy for you :) With all the resources out there and your HUGE fan club, I'm sure you'll find the perfect solution.

Kari Lønning said...

I missed this post asking for greenhouse information. I've been trying to get the propane, hot-water-circulating system in my greenhouse fixed for the last few MONTHS. I've gone through many plumbers who have thrown their hands in the air and told me that the furnace/boiler system I had is no longer made and parts hard to come by. Two weeks ago one plumber just stopped returning calls. (We were about to have our first frost (zone 5-6) I finally had Sears come out and they gave me a $7,500 quote!!! I'm off to a show this week (warmish weather predicted) but when I come back I HAVE to find something.

I'd love to know if you found out anything about heaters. Maybe we could talk?

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