Hello Guys,
I could finally find the time, and will soon start to build a new greenhouse (my wife's plants are multiplying at an enormous rate :)) It's mostly for keeping succulents safe (5-8 degrees) during the winter, but it's for 4 seasons. We are at 47 degrees in latitude, so winters can go down to -20C (-4F), and summers up to +40C (104F). In USDA Hardiness Zone this is around 6-7.
The size is about 12m2 (~130 sq ft), but can be scaled up and down. The design is a mixture of different ideas, but focus is on easy DIY construction, (relatively) low cost, and high thermal efficiency. I wouldn't say it's a professional design, but at least "enthusiast" 🙂 There are options for PWM controlled solar heating, Home Assistant / Smart Home integration, exhaust fans and humidity control.
Depending on how much electronics you want, and "how passive" you want to be (e.g. solar panels, GHGT…), the material cost is around $1000 – $1500 (at least here in Hungary).
I'm an engineer with some OCD :D, so I have a lot of calculations and a very detailed plan, up to the last screw, basically.
If anybody is interested in this, I can publish the actual building progress here, so… let me know. At the end, I will release the design specification (with photos) to the public domain.
* On the photo: not my design, but mine is very similar to this. (Source: https://extension.umn.edu/growing-systems/deep-winter-greenhouses)
by FagzalNew
8 Comments
I would love to follow your progress, I am also designing a deep winter greenhouse. I won’t start the actual building until next year so it would be great to see what others are doing.
I forgot to mention: heat loss is about 22W/K for the basic design (e.g. +5C inside, -10C outside => ~325W heating) without considering the ground heat battery, no solar panels and with single layer 16mm 4-wall polycarbonate. With double layers can be down to about 5-8W/K, and with solar extension (direct DC heating) passive (or close to) at these temperatures.
How much excavation work are you trying to do?
A couple of features to consider (if you haven’t already) for passive/low tech climate control:
-Earth sheltering on the north wall
-Thermal mass via water storage (barrels, totes, fish pond)
-air-to-ground geothermal heat loop integrated into greenhouse foundation as ‘heat battery’
-Rocket stove thermal mass heater (could be integrated into raid beds)
-solar chimney
Good luck! Lots of cool ideas and helpful videos out there. I am very jealous 😄
Look into earthships/earthship homes and see what lessons you might not have thought of yet, take what makes sense and leave the rest
Looks pretty similar to [this](https://youtu.be/TAWBnGDss8k?si=fZh-1vU-wGX5hcW-) guys greenhouse. He’s in zone 3i think so much colder and it works very well.
Looks like greenhouse. If true you will boil in the summer months
1. You will probably want a frost wall. Insulation going down into the soil around the perimeter to keep out the cold from underground. See this similar sucessful build in zone 3 for great tips. Check out his build video from 3 years ago to see how he did it. https://youtu.be/_hi_6qDsQ0E?si=Ge8IsXroXGrcR8h9
2. This could overheat even in winter. You’ll want some serious venting options like doors at each end and giant roof flaps that open up. You can’t over ventilate a greenhouse. You won’t regret having lots of vents and you don’t want to have to rely on noisy and expensive to run fans.
Cool, keep posting the progress pics!