Great talk, but one major oversight. Straw bale adobe walls should be the near universal norm. At R-2 per inch of thickness, a two foot thick straw bale adobe wall can give R-48. And at $2-4 per bale, very high insulation standards can be met for very little expense. It is lower cost than polystyrene, rock wool/fibreglass, foam, and all other insulation types I know of - and it is a mold/pest/flood/fire/earthquake- and storm-resistant, non-toxic, non-polluting, low embodied energy, carbon sequestering, generally locally sourced, renewable building material set, that does not require petrochemicals or high energy use to manufacture. Why on earth is anyone talking about any kind of design other than non-toxic, passive solar, earth-integrated where possible, off-grid, solar and wind powered, straw bale adobe construction - with an attached solar greenhouse for heating the home or building, cleaning the air, oxygenating the air, further sequestering carbon, and generating on-site food production? It seems the leading edge of green home and building design is still 40 years behind, sorry to say.
Use a intermittent Ozone generator up at the hot-air-intake, put it on a timmer and let the intake suck in a whiff of strong Ozone every so often, it will near-instantly get sucked into the T.Mass and oxidize its way through any mold/bacteria and likely be spent long before it would make it out of the exhaust. If you smelled any ozone in the structure you just dial back your generator.
The temperature difference between the top and bottom of the greenhouse shouldnt be that large, if it is you dont have enough airflow and need to install some HAF fans :)
Curious if anyone has mentioned as an ALTERNATIVE source of heat for growing in winter ... rocket mass heater? You will find that this uses about 1/4 of the wood a traditional wood burning stove would use. Typically, one can use the fallen branches in one's yard to heat an entire house of 1500 sq ft or so with JUST fallen branches from trees in a Canadian homestead. It works out to be about 25 lbs of wood per day when stove is needed. If on a somewhat lightly "wooded lot" one can achieve essentially free heat in this manner. I would encourage you to research this as you can put together a rocket mass heater for around $200 to $300 depending on size and scope. The best resource for this heating is found at: permies.com
Lee Forex rmh in greenhouse is great complimentary/supplemental heat, I wouldn't want to have to rely or decent on building daily fires out there though. I definitely plan to include an rmh and compost heat from outside pile.
Also by not creating some-type of insulation under that thermal mass you are literally Heat-sink'ing all of your gain. The earth will take all the BTU's you could ever get into this system. If 50F is a great spec, why go through this hassle at all, and just sink your Green house into the 'pit' a little, forgo the stone, tubes and everything and maybe put in a couple aluminum heat-sinks into the ground to bring up a little extra surface area to the deeper earth for the cold nights. Even R3 under that slab would have a massive benefit and barely increase the cost. I am very curious to see your long term results. I feel that $500 in savings is going to harm your performance greatly.
Insulation under the mass is a two edged sword as it also fixes the amount of mass. While it is true that heat does indeed travel downwards there are a few things to consider. If the system operates on a hand-to-mouth basis, where the bulk of the daily gain will be utilised on the same night then using insulation is not critical. If the system is to be used during the summer to cool the greenhouse, the insulation and fixed mass will work against you. I use only vertical perimeter insulation and over 7 years of monitoring i`ve noted the excess heat gained from summer cooling does migrate downwards but over the years it increases the grounds average temperature compared to ground oitside at identical depth. In my case the ground below the greenhouse averages 5 deg C warmer than the ground outside at the same depth. The ground outside tracks its original seasonal values quite closely which is to be expected as the energy balance in that ground is largely unchanged. The ground below the greenhouse is subject to a completely different regime, ie, its sheltered from the elements (wind, rain, snow etc) and energy is actively added and removed from the mass. A lot of these video`s are based on pure theory..which rarely coincides with what actually happens in a real system installed in the real world :)
JohnGuest45 Great reply! For the record I am generally not a fan of foam insulation, but over the years I've learned to respect what it can give us when used properly. This topic is 'massive' and I could talk about it forever, but I don't want to bore the hell out of you. My experiences are mostly derived from building passive solar underground/bermed housing. I'm living in my 4th-gen design as I type this now, It is by far the best performing structure I have built to date. Despite living in upstate NY, on dense, wet clay-soil with weeks of 0F days/nights. I've been able to affordably build a house that is almost always comfortable with very little input (firewood). I don't even using window quilts on my massive amount of glazing. If I did I would likely be able to avoid adding any supplemental heat for 60%+ of the coldest winter days. Part of the reason why I avoid window insulation beyond being lazy is that I actually have to take-care not to over heat the house when the sun is near its lowest arcs as my overhangs won't shade it at all. The major design difference between his structure and my previous one, is that I increased from R5 to R10 under the home, and also R10 completely surrounding all footings and up the buried walls, Essentially this house is floating on R10 footings and all. And instead of simply insulating directly under the slab I have 12"+/- of wash stone under my slab above my insulation. This allowed me to pour a fairly thin slab to save on cement costs, but have a large multi-day/week thermal battery. I was seeking to find the sweet spot between 1-3 day storage performance and true passive-annual storage. And effectively my experiences are strongly pushing me to realize that for my own personal level of comfort @ 67-73F indoor temp. Protecting my gains, is possibly more valuable than my storage volume. Though I do believe there is a sweet spot between the two. Also your soil is a huge factor I believe. The soils I live in are what I would consider to be among the worst for underground structures, Extremely hard, dense clay. It probably sucks away heat as well as solid cement! In reference to this specific Green house video, I'm trying to take what the host was staying at complete face value. This was for Deep-winter growing, Not really designed for summer-use. Trying to be cost-saving, but highly effective. I am also operating under the assuming that what is most comfortable for humans 65-75F is also near the best growing temperatures for plants. I believe that if all these things are true, by not insulating under the slab, this whole green house will be closer to 50F than 70F+ more often, than if it had even a small amount of insulation. Which is why I mentioned if 50F was desirable, why go through all this hassle in the first place, You could damn near-dig 4' trench, with a 1-2' deep cold-sink on the south side of it, put a double-layer-blower membrane above it extending several feet past both sides of the trench and go to town. It would hardly fall below mid 40's at night, and whenever the sun was out your plants would be in that ideal-grow zone temperature. This method has worked forever. It would cost a fraction of the structure presented here and be built as fast as you can put up a small hoop house and dig a hole. It looks like the host is trying to have better conditions than a freeze protected sunken green house. So my assumption is he is hoping for as much 60-65F+ as possible. I do believe if this is the case, some de-coupling from the earth would be a big benefit. These types of structures shed snow really well. And they still get a good amount of heat even in cloudy weather. I believe that with no insulation the Earth is going to keep sucking away your BTU, always trying to drag you to 50F on those cloudy days. If you put R10+ under a large heat-sink. Even on those cloudy days you could be adding BTU to the system, or at least coasting longer on what you have because you are not loosing it so much on both ends (outside at night, and under all the time) I guess that would be a simple way I would try to explain my point. By putting insulation under the slab, you are loosing less total BTU's per day from the structure. Perhaps by a very large amount. Under no circumstances with a big enough heat-sink (3-4'?) would I fear you would have so poor weather as to exhaust your thermal mass and and then wish you had access that to that 50F ground temp. Even at R10 that earth is still influencing your storage. Just to a lesser extent. I'm sure we can actually map this with some good FEA software or something. But my 'gut' is telling me, this is mostly a all or nothing situation, and you are either best suited by building much more SQFT, of cheaper/faster (no insulation) and experiencing slower plant growth offset by simply having more square meters in production. OR insulate the hell out of all your mass and run active systems to always try to keep you in that 'sweet spot'. Wow, sorry that was so long winded!
svojoe The keyword is deep winter "growing", so the design emphasis should be on light rather than heat. For deep winter plant "survival", the temperature only really needs to be kept above freezing. Active growth requires light which is usually in short supply as the winter suns azimuth is much lower and the arc is much shorter. This is important as the low azimuth light must pass through more of the earths atmosphere. Winter also brings a lot of cloudy, overcast days and the light is mainly of the diffused variety. By definition, it arrives from all directions so insulating the northwall comes with a light cost if growing plants is the goal. Attempting to heat the air in a typical 12ft high greenhouse with plants that are a foot tall is unfathomable :) Especially when the envelope containing that air has a negligable R-value. Its akin to living in one room and heating the entire house with all the windows open.
Hi Svojoe, How much dirt do you earthberm your homes with in NY and are they domes? If everybody did this the acceleration of global warming would be solved. It works anywhere in the world.
Its covering most of the east-west walls and all of the north facing walls, Its bermed up to around 8' tall, And its double-insulated at the very top 4' of the wall as the soil is thin up there and won't provide a great deal of protection from the ambient temps. The berm does require maintenance, you need to make sure you have a good drainage plan so it doesn't erode, and make sure it doesn't pull down any water-membrane you are using and it will 'sink' over time until it fully settles which can take years. However, it saves many thousands of dollars in exterior siding/finishing etc and you can plant clover on it for the native pollinators like I do.
Horrible audio..loud first half of sentence, then mumbled the important stuff. Had to turn it off due to inability to hear the mumbles, especially while wiping face putting hand infront of mouth...lip reading out of the question.
never had a hard time listening to a presentation, just because of a repetitive phrase... "ya know"... lol I had to shut it off about half way thru... like, DANG!
Please, be aware of many times you say “um”. I know public speaking can make a person nervous but it’s so distracting I cant listen as much as I want to hear this.
Great talk, but one major oversight.
Straw bale adobe walls should be the near universal norm. At R-2 per inch of thickness, a two foot thick straw bale adobe wall can give R-48. And at $2-4 per bale, very high insulation standards can be met for very little expense. It is lower cost than polystyrene, rock wool/fibreglass, foam, and all other insulation types I know of - and it is a mold/pest/flood/fire/earthquake- and storm-resistant, non-toxic, non-polluting, low embodied energy, carbon sequestering, generally locally sourced, renewable building material set, that does not require petrochemicals or high energy use to manufacture.
Why on earth is anyone talking about any kind of design other than non-toxic, passive solar, earth-integrated where possible, off-grid, solar and wind powered, straw bale adobe construction - with an attached solar greenhouse for heating the home or building, cleaning the air, oxygenating the air, further sequestering carbon, and generating on-site food production?
It seems the leading edge of green home and building design is still 40 years behind, sorry to say.
Hot Water in floor is actually a very good idea. Proven in residential use for a very long time. Heat. Exchanges cheaper than excavators
incentive for air flow is not an engineering term. It is all about air pressure. Negative pressure equals suction.
Tons of great info, thank you for making this available!
Use a intermittent Ozone generator up at the hot-air-intake, put it on a timmer and let the intake suck in a whiff of strong Ozone every so often, it will near-instantly get sucked into the T.Mass and oxidize its way through any mold/bacteria and likely be spent long before it would make it out of the exhaust. If you smelled any ozone in the structure you just dial back your generator.
Net zero USED to be expensive. The cost of technologies has plummeted since 2016.
The temperature difference between the top and bottom of the greenhouse shouldnt be that large, if it is you dont have enough airflow and need to install some HAF fans :)
You should put up a higher resolution file- 720p is good.
video is uploaded at 800p. video camera used to record this one wasn't the best, but we're working to improve the quality. thanks for commenting.
glad to see the design I have been planning and finally built this summer isn't to far off from the experts. I live in ne ohio. jim
good luck with your greenhouse!
Adapt2030. This will be great for ice age we are entering. Ty!
Pit greenhouse are efficient only near the equator.
Curious if anyone has mentioned as an ALTERNATIVE source of heat for growing in winter ... rocket mass heater? You will find that this uses about 1/4 of the wood a traditional wood burning stove would use. Typically, one can use the fallen branches in one's yard to heat an entire house of 1500 sq ft or so with JUST fallen branches from trees in a Canadian homestead. It works out to be about 25 lbs of wood per day when stove is needed. If on a somewhat lightly "wooded lot" one can achieve essentially free heat in this manner. I would encourage you to research this as you can put together a rocket mass heater for around $200 to $300 depending on size and scope. The best resource for this heating is found at: permies.com
Lee Forex rmh in greenhouse is great complimentary/supplemental heat, I wouldn't want to have to rely or decent on building daily fires out there though. I definitely plan to include an rmh and compost heat from outside pile.
Also by not creating some-type of insulation under that thermal mass you are literally Heat-sink'ing all of your gain. The earth will take all the BTU's you could ever get into this system. If 50F is a great spec, why go through this hassle at all, and just sink your Green house into the 'pit' a little, forgo the stone, tubes and everything and maybe put in a couple aluminum heat-sinks into the ground to bring up a little extra surface area to the deeper earth for the cold nights.
Even R3 under that slab would have a massive benefit and barely increase the cost. I am very curious to see your long term results. I feel that $500 in savings is going to harm your performance greatly.
Insulation under the mass is a two edged sword as it also fixes the amount of mass. While it is true that heat does indeed travel downwards there are a few things to consider. If the system operates on a hand-to-mouth basis, where the bulk of the daily gain will be utilised on the same night then using insulation is not critical. If the system is to be used during the summer to cool the greenhouse, the insulation and fixed mass will work against you. I use only vertical perimeter insulation and over 7 years of monitoring i`ve noted the excess heat gained from summer cooling does migrate downwards but over the years it increases the grounds average temperature compared to ground oitside at identical depth. In my case the ground below the greenhouse averages 5 deg C warmer than the ground outside at the same depth. The ground outside tracks its original seasonal values quite closely which is to be expected as the energy balance in that ground is largely unchanged. The ground below the greenhouse is subject to a completely different regime, ie, its sheltered from the elements (wind, rain, snow etc) and energy is actively added and removed from the mass.
A lot of these video`s are based on pure theory..which rarely coincides with what actually happens in a real system installed in the real world :)
JohnGuest45 Great reply! For the record I am generally not a fan of foam insulation, but over the years I've learned to respect what it can give us when used properly. This topic is 'massive' and I could talk about it forever, but I don't want to bore the hell out of you.
My experiences are mostly derived from building passive solar underground/bermed housing. I'm living in my 4th-gen design as I type this now, It is by far the best performing structure I have built to date. Despite living in upstate NY, on dense, wet clay-soil with weeks of 0F days/nights. I've been able to affordably build a house that is almost always comfortable with very little input (firewood). I don't even using window quilts on my massive amount of glazing. If I did I would likely be able to avoid adding any supplemental heat for 60%+ of the coldest winter days. Part of the reason why I avoid window insulation beyond being lazy is that I actually have to take-care not to over heat the house when the sun is near its lowest arcs as my overhangs won't shade it at all. The major design difference between his structure and my previous one, is that I increased from R5 to R10 under the home, and also R10 completely surrounding all footings and up the buried walls, Essentially this house is floating on R10 footings and all. And instead of simply insulating directly under the slab I have 12"+/- of wash stone under my slab above my insulation. This allowed me to pour a fairly thin slab to save on cement costs, but have a large multi-day/week thermal battery.
I was seeking to find the sweet spot between 1-3 day storage performance and true passive-annual storage. And effectively my experiences are strongly pushing me to realize that for my own personal level of comfort @ 67-73F indoor temp. Protecting my gains, is possibly more valuable than my storage volume. Though I do believe there is a sweet spot between the two. Also your soil is a huge factor I believe. The soils I live in are what I would consider to be among the worst for underground structures, Extremely hard, dense clay. It probably sucks away heat as well as solid cement!
In reference to this specific Green house video, I'm trying to take what the host was staying at complete face value.
This was for Deep-winter growing, Not really designed for summer-use. Trying to be cost-saving, but highly effective.
I am also operating under the assuming that what is most comfortable for humans 65-75F is also near the best growing temperatures for plants. I believe that if all these things are true, by not insulating under the slab, this whole green house will be closer to 50F than 70F+ more often, than if it had even a small amount of insulation. Which is why I mentioned if 50F was desirable, why go through all this hassle in the first place, You could damn near-dig 4' trench, with a 1-2' deep cold-sink on the south side of it, put a double-layer-blower membrane above it extending several feet past both sides of the trench and go to town. It would hardly fall below mid 40's at night, and whenever the sun was out your plants would be in that ideal-grow zone temperature. This method has worked forever. It would cost a fraction of the structure presented here and be built as fast as you can put up a small hoop house and dig a hole.
It looks like the host is trying to have better conditions than a freeze protected sunken green house. So my assumption is he is hoping for as much 60-65F+ as possible. I do believe if this is the case, some de-coupling from the earth would be a big benefit.
These types of structures shed snow really well. And they still get a good amount of heat even in cloudy weather. I believe that with no insulation the Earth is going to keep sucking away your BTU, always trying to drag you to 50F on those cloudy days. If you put R10+ under a large heat-sink. Even on those cloudy days you could be adding BTU to the system, or at least coasting longer on what you have because you are not loosing it so much on both ends (outside at night, and under all the time)
I guess that would be a simple way I would try to explain my point. By putting insulation under the slab, you are loosing less total BTU's per day from the structure. Perhaps by a very large amount. Under no circumstances with a big enough heat-sink (3-4'?) would I fear you would have so poor weather as to exhaust your thermal mass and and then wish you had access that to that 50F ground temp. Even at R10 that earth is still influencing your storage. Just to a lesser extent.
I'm sure we can actually map this with some good FEA software or something. But my 'gut' is telling me, this is mostly a all or nothing situation, and you are either best suited by building much more SQFT, of cheaper/faster (no insulation) and experiencing slower plant growth offset by simply having more square meters in production. OR insulate the hell out of all your mass and run active systems to always try to keep you in that 'sweet spot'.
Wow, sorry that was so long winded!
svojoe
The keyword is deep winter "growing", so the design emphasis should be on light rather than heat. For deep winter plant "survival", the temperature only really needs to be kept above freezing. Active growth requires light which is usually in short supply as the winter suns azimuth is much lower and the arc is much shorter. This is important as the low azimuth light must pass through more of the earths atmosphere. Winter also brings a lot of cloudy, overcast days and the light is mainly of the diffused variety. By definition, it arrives from all directions so insulating the northwall comes with a light cost if growing plants is the goal. Attempting to heat the air in a typical 12ft high greenhouse with plants that are a foot tall is unfathomable :) Especially when the envelope containing that air has a negligable R-value. Its akin to living in one room and heating the entire house with all the windows open.
Hi Svojoe,
How much dirt do you earthberm your homes with in NY and are they domes?
If everybody did this the acceleration of global warming would be solved. It works anywhere in the world.
Its covering most of the east-west walls and all of the north facing walls, Its bermed up to around 8' tall, And its double-insulated at the very top 4' of the wall as the soil is thin up there and won't provide a great deal of protection from the ambient temps.
The berm does require maintenance, you need to make sure you have a good drainage plan so it doesn't erode, and make sure it doesn't pull down any water-membrane you are using and it will 'sink' over time until it fully settles which can take years.
However, it saves many thousands of dollars in exterior siding/finishing etc and you can plant clover on it for the native pollinators like I do.
Now we talking
Horrible audio..loud first half of sentence, then mumbled the important stuff. Had to turn it off due to inability to hear the mumbles, especially while wiping face putting hand infront of mouth...lip reading out of the question.
I counted nearly 100 "um's" by the 20 min mark.
never had a hard time listening to a presentation, just because of a repetitive phrase... "ya know"...
lol
I had to shut it off about half way thru... like, DANG!
Please, be aware of many times you say “um”. I know public speaking can make a person nervous but it’s so distracting I cant listen as much as I want to hear this.
Um, um, um, ah, um. Very distracting. Hope I can find this information presented by someone else.
Hey. It’s a good presentation, great info.!