Help with lean-to greenhouse purchase - Orchid Board

Bayard · #1 05-25-2020, 07:04 PM

Hi WaterWitchin,
The greenhouse is heated with a Southern Burner (now discontinued) 24,000 BTU natural gas heater. It is adequate except for the coldest, windiest nights when I add an oil filled electric radiator to the cold end. The most we’ve paid for gas is $400 in a month, but that includes heating the house as well. I’m not happy with the options for replacing my Southen Burner, so I’m looking into a hot water radiant system to replace it. It would have a remote boiler and radiators with fins around the periphery.

WaterWitchin · #2 05-26-2020, 11:52 AM

Quote:

Originally Posted by Bayard

Hi WaterWitchin,
The greenhouse is heated with a Southern Burner (now discontinued) 24,000 BTU natural gas heater. It is adequate except for the coldest, windiest nights when I add an oil filled electric radiator to the cold end. The most we’ve paid for gas is $400 in a month, but that includes heating the house as well. I’m not happy with the options for replacing my Southen Burner, so I’m looking into a hot water radiant system to replace it. It would have a remote boiler and radiators with fins around the periphery.

That's kinda scary. We do a level payment plan for gas, and it runs around $90+/- per month averaged over a year. That's a significant difference. About an 1800 sq foot house, with around 30 leaky windows in the areas we heat/cool. 90% efficient natural gas furnace. No insulation in walls, just lath/plaster. A gas fireplace that gets used daily for about 6 hours because husband is cold-blooded.

Maybe our natural gas is cheaper? Maybe it gets a LOT colder for more days your way than here? Maybe your house is a lot bigger or y'all keep it a lot warmer? We keep thermostat in winter at 69F.

Hmmmmm..... And these are EXACTLY the kinda things I want to find out prior to taking the leap.

---------- Post added at 10:52 AM ---------- Previous post was at 10:39 AM ----------

Quote:

Originally Posted by Keysguy

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Anyway....it was a 12' x 16' aluminum frame shed roof or "lean to" type structure attached to south gable end of the house. Roof and end walls were 8mm double wall poly and long outside wall was doublepane glass. Remember this was 15 years ago so there is way better technology available now. Dug down and poured footings and a concrete floor with 2 drains. Concrete was stained terra cotta color to promote the concrete retaining heat in winter. (all my plants were in outdoor shadehouse from Memorial Day to mid- Sept.) This was in central NH so probably a harsher winter climate than what you have. Exhaust fan high on east end wall, 2 intake shutters low on west wall. All automated on a thermostat. (should have done those exactly the reverse, in from east (cooler) out to west).

During design, we had to modify the canned structure design to accommodate ability to have the top of roof tuck under second story house windows but still give us adequate roof pitch for snowload structural support. Removed a window in the house living room and replaced it with a glass exterior door for access to the GH from house. GH had a door on west end.

I put in auto misting in one area, ran hot & cold water and propane from house. Empire thru-wall propane heater was adequate most of the time but when it wasn't I had an electric space heater I ran in opposite end for "support". I also put 4 layers of thick plastic over the door and all 3 vents from mid Dec to mid March. Propane was still $300/month and that was to maintain 55 degrees. ...

A note on the water...... I added a mixing valve so I could have tepid water for watering in the winter vs. shocking them with 38 degree well water....

Sounds very similar to what I want... right down to the window removal and door put in on house side, the south side of house, the plumbing in water/electric (which I don't have to do as I have access from a basement window. And running a duct over from the furnace.

This will be about a 13x11 lean to (builder was here yesterday and that works better for my situation). West and East walls will be insulated solid walls except for a window on each side, exhaust shutter on east, exhaust fan and door on west. The south side of greenhouse will be 8' total... 4' of base wall insulated and 4' of poly panel. Top all poly panel. Right now I'm looking at 16mm panels. Base of greenhouse gravel with pavers for walkways.

Again, someone who is spending a lot more on heating than I've ever done. Could a greenhouse really add $300 a month to my gas bill? Holy Cow.