My Dad ran a closed loop system back in the mid 1970's ...same as yours. He used 2-aluminum car radiators stacked back to back zip tied, with connector hoses. To presure our closed loop line we used a hot water base board pump. He used a thermostat switch that powered a AC-fan and was the same switch that powered the pump. He used RV (pink) fluid for the lines. Later he put a line (burper), basically to get rid of air in the lines, but really didn't need to do that. We were fortunate enough that we had our own backhoe to lay our lines. I cut 4 ditches @ 5' × 16" × 100' runs and we sand bedded the bottom of the trenches...laid a DOUBLE line (4 loops) and sand bedded again. Than backfield dirt to about 12" from the top. AGAIN sand bedded about 4"deep...ran a second DOUBLE LINE (4loops), sand on top and about 6" of topsoil. SO HE MADE A STACKED.....AC/HEATER BED.AC on the bottom, heat on the top lines. Simply attached those lines to a 2 seperate-4 way splitter and used a BALL VALVE TO SEPERATE THE UPPER AND LOWER CLOSED SYSTEMS. The splitters joined to a single line and ran to the line circulator pump....and a single line ran from there to the radiator. A return back line from the radiator was to a 2-way splitter controlled by a single ball valve. During the summer rotate 2 ball calves one direction for AC/bottom lines.......during winter rotate both ball valves the opposite direction for heat/top lines. WE STILL USE THE VERY SAME SYSTEM TO THIS DAY.......ONLY THING REPLACED was 2 circulator pumps over the pass 45yrs. Our hose bed at the bottom has spring water feeding to it. On AC our house will drop to 61-62°F and freeze you to death if left on constantly (so the themastat switch) was a must. Heating....can't say it's the best...helps in early spring but not as a primary source up here in the North Country. So the system turned into TOP LINES AS A PRECOOL and BOTTOM LINES AS THE COOLER....FOR A.C. ONLY !! THE BEST A.C. EVER....SUPER CHEAP....AND CAN BE RUN ON DC SOLAR POWER 24/7

It works I tested mine that I put in late last fall. 1inch x 400ft , 160 psi here in upstate Burke NY . It was 90 degrees today It was 60 degrees in my insulated wood shop. I will be put another loop in for my home

I have to tell you and everyone reading this - apply this knowledge to your next digging project - such as your house being built new or any excavation you have. The biggest problem is most people will not plan ahead enough to simplify there life in the new future . Great video and very inspirational .

Needs less emotional selling and considerably more technical how-to, specifically linear feet of cooling tube per cubic foot of conditioned space requirements

I built one about 20 years ago and still working. Just recently replaced the circulation pump with a more efficient Grandfos circulation pump and a new radiator . Also I have another loop away from the first one and I am dumping heat into the ground in summer with a passive evacuated solar panel to warm my workshop in winter ( obviously changing the passive solar panel with a radiator . It work brilliantly and very cheap to run .

Great solution! Some additional info: 1) ALWAYS call for utility locator before digging! (Blue Stake or dial 811 in US). 2) You may want to also add a dehumidifier. Conventional AC units dry the air when cooling it. You may want to extract some of the interior air moisture, especially during late summer. 3) Glycol-based coolants can prevent corrosion in the radiator. Water does not. Something to consider. 4) The radiator (especially if the air isn't dry) can produce moisture. Think of a cold can of beer on a hot summer day. Consider including a pan to catch moisture under the radiator and draining it outside.

I was days away from starting an install of the other system you described. I was going crazy trying to figure out solutions to all the problems you mentioned in this video. I stalled on the project until I could figure them all out. I'm so happy I ran across this video! This solves ALL the problems! Thank you so much. I will be watching all your videos from here on out. I have an off grid homestead in the TN mountains. I love the lifestyle, and am always on the look out for new projects that will make life more comfortable.

In the interest of longevity of a water bases system - it's worth mentioning galvanic corrosion, in short - avoid using dissimilar metals in the loop ( talking anything in the radiator, pump, potentially metal tube fittings ) don't mix copper, aluminium for example, one type of metal only.

Holy hell, what a useful video! I'm kind of ashamed to say that I never thought of this as a possibility for year-round heating and cooling after reading an article about using geothermal for in-floor heating.

I feel compelled to point out that a system like this doesn't even need to completely cool or heat an area all on its own. Even if it only reduces demand for traditional heating or cooling systems, that's worth a lot, especially over the many years this system will continue working. It also occurs to me you could integrate such a system with some sort of thermal battery to "save up" the thermal energy produced during times when you don't immediately need it. For example, you don't need as much if any cooling from this system at night during summer, but with a thermal battery of some kind you could be saving up that extra cold for use during times of peak need during the day.

I saw this last year and loved it. I did all this and became stuck with all the connections inside the greenhouse. I was getting a lot of leaking and so ended up using changing from the traditional pvc connectors and pvc glue etc, to using a garden hose connection system. I connected a garden hose from the radiator (there are adaptors to go from pvc threads to garden hose threads) to a garden hose connection and used garden hoses between the pump, the radiator, the tubing system etc. It doesn't leak and it is amazing. Works great. Thank you.

One thing you will want to do if you are using washer fluid or antifreeze is to pay close attention to the amount in your system. If you suddenly are adding a jug or two a month, you probably have a leak and that could contaminate groundwater which depending on your soil and topography could kill gardens, fruit trees and even threaten wells used for drinking water. My parents have a fluid level monitor on their “heat pump” for exactly this reason. Their loops are just below the frost line, but even so, Code required it because of the sandy soil and a shallow water table that is both depended on for drinking water and interconnected with all the local lakes.

That's a very sustainable solution! People doing videos about homesteading should know about this system.

I did a version of this, but I'm using it to cool the floor in my workshop in the summertime. It works great. I heat with propane in the winter. But I like having the ground loop as backup for freeze protection if I really needed it. I also did a open loop geothermal air intake setup for my greenhouse also works great.

I heat my house using a heat pump. The pipes are drilled 2x90m (300ft) into the earth. My best investment were the additional 400 bucks for passive cooling the house in the summer using the infloor-heating lines. Your DIY solution for just cooling is so simple and cheap and easy to maintain. Thank You.

Thank you for sharing this, love this kind of thinking. Literally have a source of heat/cool that we’re not taking advantage of. I just don’t understand why these geothermal companies charge so much to dig and place the loop. 10k-20k just to dig is ridiculous.

Maybe I missed it but as long as you're running anti-freeze this should also work as a base load heater in colder climates if the ground temp down there is fairly high. If ground temp is 60F, that's 28F less heating from the freezing point you have to pay for. You would only need to pay for heating from 60F (minus efficiency losses) to around 72F. That's about a 12F delta instead of 40F... a 70% saving in fuel costs.

I've been thinking of this myself for YEARS and here I see a video of it, so it does work, and it really is that simple.

Great info! What a fun experiment to start on! I’ve been fiddling around with ideas similar for a while! Thanks for the push!

Mr. ST talked about 400 feet of 3/4 inch water line. In case anybody (like me) was wondering how much washer fluid that means the system will need, a 3/4 inch line holds about a gallon for every hundred feet.

This is so cool! Thank you to all the smart people who are leaving these amazing well-thought-out and detailed comments full of useful explanations thank you

One thing that is realy important. Call for utility locates. Dial 811 in the US or what ever number is used where you live. Some utility's are very dangerous and expensive to repair if you damage them. The liability and repair costs are on you if you don't get locates. They will tell you all the rules. Some utilities were installed decades ago before the neighborhood or houses were built. They turn up anywhere and are completely legal. Generaly they only locate the public utilities and not your under ground; gas, electrical, sewer, and phone lines. If you are worried about the pipe you can generally order the same pipe with heavy duty thicker walls. It won't bend as sharply and may require a wider trench, the manufacturer can tell you. Also ask about repairing kinks.

Hey boss! I'm in love with this video! So much so that I'm going to copy and paste your idea into my own project. I'm planning on expanding my house in the next 1-3 years and I need an upgraded condensing unit... Until I saw this video! I'll be making progress videos, once I get started, using your method! I'll start this project sometime next year (due to finances). This year I'll start getting the materials together you listed in this video. Thanks so much and hope to share with you as I go!

The design of our house has a 4’ crawlspace buried in 4’ of gravel. The idea was to keep the house cool (and warm in winter) and a crawlspace of course. We will see how well it works this summer. I’m thinking it won’t be enough so am considering a ground loop similar to this video.

For helping keep the greenhouse warm in the winter, you can build a rocket mass heater (for free, if you want!) that you only have to run for an hour or two each night or when it gets *REALLY* cold out.

This is cool and I can tell you're excited. I'm a US Green Building Council LEED AP and you've just given me my next project for my cabin on 50 acres in the mountains of West Virginia. My neighbor has a large excavator and this will be perfect. Thanks!

I just want to thank google for ease dropping on my conversation yesterday and suggesting your video today. You've got a new subscriber out of it too.

Great video ST... You Rock ! Liked/Subscribed ! I appreciate all that you put into these Free Instructional Courses !

Probably will never build one, but this is just fascinating! Really enjoying these greenhouse videos! But it does beg the question... if you are renting an excavator, why wouldn't you just dig the whole greenhouse down about 2 feet? Sure, take some water precautions, but I'd imagine you would want some sort of sump/cistern solution for water reclamation anyways (combined with a gravity fed water drip system). But just digging down a couple feet would allow the floor and lower 16" of 'wall' to constantly help regulate temps in summer and winter. But I am not sold on this as a good way to cool a greenhouse. At the end of the day this just isn't going to put out the same kind of cooling as a $1-2000 window unit. This would be more like using a $200-300 unit... but running on 100W instead of 500W. More efficient for sure... but how long it would take to use $800 worth of electricity using a small wall unit vs the time and effort and cost of doing this kind of passive geo setup. The cheapest and most effective way to cool things is an intake fan, and an air gap in a high place. That alone should be able to get things down to near-ambient temperatures, and with a few strips of cardboard and a drip system you can get slightly below ambient with a home-brew evaporative cooler (with oppressive humidity lol). Most crop plants are quite happy at 90*f, and don't really start being damaged until there are sustained temps above 100*f. If your temps outside are above 100*f, then you need a more active cooling solution... problem is that you are in a greenhouse with extreme amounts of solar gain! You could cover the glass, but that kinda defeats the point (maybe a mesh blanket to provide some shade?), so the other option is conditioning the air, which means sealing the system for best efficiency. But in a greenhouse you are then dealing with extreme amounts of heat gain to purge, which is why you would need such a large beefy AC during those times. Again, passive geo would help supplement a larger AC unit, or maybe allow you to get by with a smaller unit... but at that cost vs power costs... I'm just not sure you would ever hit a break-even, especially if you bill yourself for your digging efforts (which you should!). But for heating... that would be a different story entirely. For heating you want everything sealed anyways, and you just have so many other potential heat sources. During the day you are almost guaranteed free heat from the solar gain, so the trick is storing that heat to release at night with a thermal mass of some sort; large black barrels of water, a big back masonry wall, even the ground itself is going to give off a certain amount of heat. The 2nd trick is to then retain heat by preventing air exchange, reflecting heat (mylar is cheap!), increasing r-value with a blanket over the glass and insulated walls. Third trick is then adding heat if needed. If you have any real amount of power available, then the first thing that comes to mind is to add grow lights - have them turn on for a couple hours in the early morning (coldest part of the day), and they will add heat, and also extend the daylight hours, and it would be super cheap to implement and set up. 2nd thought is a cheap emergency heater... probably want one anyways for a freak cold dip, and if a cheap $30 heater just needs to run for a night or two to keep the crops alive... well... like the AC, it is going to take more than a few nights to make the geo worth doing. BUT, just keeping the plants alive and above freezing may not be ideal. Keeping them closer to 40-50*f at night could produce better growth and harvests, which that alone could make the passive geo system worth it. The thing to look out for though is that it is passive, so if you are in a more temperate winter area, then during the day the greenhouse might get above 50*, at which point the system is removing heat, instead of adding it. So put it on a thermostat, and if it gets much above 50, then be sure to turn it off so you can build up as much heat as possible before things dip below 50 again in the evening. But again... if you are renting an excavator, and you just dig down 2-3', then you are going to get a lot of these benefits of temperature regulation for free anyways without need of worrying about pumps breaking or water lines failing. The real lesson here is that if you are going to pay for an excavator, then dig the trench and bury the line anyways so it is there as a potential future option... but really just bury the building as much as you can. It isn't going to affect your sun intake, and will help a lot with temperature regulation during those cold winter months especially. The best passive geo is going to be when you don't need anything to make it wok for you in the first place.

Interesting idea, but I’d add a few suggestions. First your radiator , the thicker it is the more thermal transfer you’ll get. A four core radiator would be what I’d look for, unfortunately more than 2 core is very hard to find but you can order four core radiators from performance shops like summit racing, desert cooler and I think jegs. The cooling liquid, ammonia can be harmful to aluminum, propalyne glycol (rv antifreeze, the red/pink stuff) is a much better idea, it can be mixed with water to a certain degree. As far as keeping the system free of air you can install air purging valves, for refilling you can add an auto fill for a boiler but make sure to use a small backflow preventer before the auto fill if connected to your domestic water pipes. Those parts can be found at heating supply shops that carry hydronic stuff. I’d suggest “taco” ( actual brand) air purge valves and watts makes good auto fill and backflow preventers.

Use a ditch witch trencher from Home Depot and lay in 4” pvc schedule 40 if you don’t have to go too deep. I used that method for a Kiva I built in the ground in Durango. I just made a 200’ run in a big loop around the property and used a couple of little computer fans in a push/pull configuration. Worked awesome in summer.

I'm glad I found this video because most of the content on this topic is focused on larger and more expensive versions. Only issue for me is that there is a tree which blocks excavator access. We had one here in the 1980s, but the tree was considerably smaller back then. Anyway, now I'm looking into how practical it is to disassemble and reassemble a mini-excavator before I plan the old fashioned way.

Very Interesting idea, especially since my A/C blower just took a dump and I have about 100' of the pipe lying around for what I thought was an outside water leak and I just kept it in case. In case may have just happened...Thanks for the idea.!

Brilliant idea! It's a low efficiency refrigerant-free closed loop system that is dead simple and cheap. Simple is great for maintenance. I would put multiple branches in the ground that T off of the main lines from/to the pump, keeping theT above ground. Though I wonder how long the pump and radiator will hold up to the corrosive methanol/ethanol in the all season windshield washer fluid. Maybe the propylene glycol based RV/Marine antifreeze would be better? They are also cheap and safe to handle and usually contain corrosion inhibitors. BTW propylene glycol is used in industrial heat transfer fluids.

I know this video is a general idea with all but the nitpicking details added. Thank you for this. I had a couple thoughts that really don't fit anywhere, but maybe someone could use. On the fan, if you use a box fan, mount a air filter to it. That way you filter the air in your workshop, or basement, or garage. It will save the radiator from getting plugged, especially if the fins sweat/condensate. Also a tubing like this run through an attic in the summer could heat a pool. I remember reading about a radiator mounted in an attic to grab the attics heat for a pool heater. Anyway looking forward to seeing some of your other videos. 😊

Exactly. Base loading and mass balancing is the name of the game. If you can reduce the amount of heat you have to produce by 50%, you're winning now and later. Base load for the win.

I used to work for a geothermal installer. He used a 50/50 mix of methanol and distilled water. Got the methonal (DRAGSTER FEUL) at the local drag strip for cheap.

I just built a diy AC this year. I literally just took off the outside heat exchanger from the busted split ac unit and piped well water through the coolant pipes. 16C well water 100 liter an hour solves my problem. The indoor blower that i wired to bypass the original pcb consumes 15 watts. The well pump runs like 1 / 10 of the time and consumes like 600 watts. So average 75 watt for the whole thing. You can irrigate with the water that runs through the ac, or let is just drain through the soil to find its way down to the watertable. Spent a hundred bucks worth of local money for all the plumbing and electrical supply i used. But honestly, for the same performance, you can just hook up a garden hose and be done with it for free. Now this off course presumes you have a nicely compatible well. A low powered well pump works great with this, like those 100 watt pulsing cheapo stuff. Or a normal 500- 1000 W pump with a water tank. Key is to not run a big pump continously with a small flow, wasting a lot of energy.

This is excellent. Thank you for sharing. You seem very knowledgeable, and your passion for this idea is very clear in your delivery. I love learning from someone who is clearly passionate about their work.

Thanks for the video. Not relevant at this moment, but it’s changed my opinion on what to look for and think about when it comes to geothermal

i have this in hungary cc 30years ago. except i dont use a pipe spiral, but i have a 250W pump in a well. the earth temperature in hungary around 11C at winter and summer aswell not much water need to cool down a house. and after cooling i drive this water into a rainwater storage and use to garden watering. yesterday was 40C here and kept the 25C inside.

Build it .. see if it works as expected. Can you connect with a hose to cold water (pump) to the Greenhouse heating rad you already have and kick the fan on for a couple house.. ?

PEX tubing buried in soils containing iron oxide can degrade prematurely. Even iron oxide rich water flowing inside the tubing can have negative effects. You also want to pressurize the fluid to 30psi and vent any air out, to prevent corrosion and reduce the load on the circulator pump. I would spend the extra change and use a proportional speed fan control/thermostat, with a squirrel cage fan for slow start and low decibel design.

I’m using this system to heat/cool my 10x20 greenhouse. So I need the 400 feet of line for this space? Also, if I’m coiling the line, could I dig a 20 foot long trench and be okay? Thank you!

My wife and I had a contractor install a Water Furnace heat pump in our home, about 25 years ago. It is a great system. What you are presenting is, as you have said quite a bit cheaper, and nearly as good for the cooling season. I will add a couple cautions before you get started. If you have a trench that is more than four feet deep, stay out of the thing. If you are in the trench, and a wall caves in on you at belly button height, you can suffocate with your head out in the sunshine, as you will not be able to inhale. Crazy isn’t it. Ask a pipe layer. Another thing to be cautious of is draining the condensate away from the radiator, and to the ground outside. Does anyone remember reading about “Legionnaires Disease”? The standing water can feed treacherous molds, which when combined with the fan, can kill your family.

Ha! Back in college we jury rigged a system like this. Except our town home had free water and the water was metered for the entire complex. Giant floor fan, 2 car radiators, and Our water supply was from a faucet. Worked pretty well

i feel like you just told me a secret, thank you for your taking the time to explain this powerful knowledge.

I wish I could like this video twice! Thank you! I don't know why we are not using these systems more in Canada.

You sir are a genius and the demonstrations and explanations were 1000% spot on. You’re very practical to understand and approach is great. Thank you!

Be very nice to see a build and then in use video. Love the idea and will look at it for my future green house and my garage

Plus, you can hybrid the cooling tubes, with solar heated tubing sections turned on for winter, with a modest backup boiler in very cold areas.

Just curious if you would know of any calculations to determine if I could attach this to an existing radiant floor heat system and directly pumped the cooled water through the pipes in the floor, would it have any cooling effect within the rooms of the house?

I did something similar one summer to cool my parents garage. Similar principle but instead of buried line, they had a Cistern right next to the garage and used a little pump to circulate cistern water thru a cheap $20 radiator i bought off craigslist. Worked quite well but produced alot of condensation on hot summer days. Needed a better condensation tray.

I live in the midwest and installed a 5 ton geo thermal unit in my house. The average cost is approximately 3 times the cost of a standard HVAC system. Unless you live far to the north there is no need to dig so deep, mine was 5 ft deep and was dug by a trencher. For every ton of unit you need 500 ft of pipe in my case 5 lines connected to a header with one line from the header coming into the house under the foundation ( new construction). The average payback time for the whole system is 5 to 6 years. Geo thermal units are 400% effecient compared to the best standard HVAC unit. My heat exchanger rarely ever came on as my house was extreamely well insulated. I highly recomend these units to anyone. One last benefit you can also make hot water for your water heater in the summer time for free.

Just curious, If you have an existing minisplit that is failing, would it be possible to retrofit a fan system from a minisplit to act as the fan and just run the fluid through the existing piping in the fans system instead of gas?

You have opened my eyes, thank you sir. Now to get this setup done at my Long beach property in Washington.

Have to say this is one of the most interesting systems I've seen on your channel! I've been looking for an alternative to the portable evaporative cooler I have been using in my "2+1" garage and workshop. It works OK for cooling in the summer (high desert of New Mexico) but uses quite a bit of water, and we are in this longterm drought. Plus, it's of course useless for heating in the winter. Hoping you are coming up with an instructional how to on this? A really really detailed how-to for the tech-challenged portion of your subscribers (like me)? Thanks! Dave

im glad you differentiated between these types of systems and GAHT ( ground air heat transfer) systems.....I didn't know about the liquid loop based systems until your and a couple others' videos, seem a LOT more resilient and that's good to know. I hate when people talk about an inferior alternative when there is a better solution that is still cheap.

Excellent channel! We love and appreciate you! Thank you for caring for us!

Sorry if I'm resurrecting an old video, but I have a question regarding land size. I do live in the city, but if we're only talking about 400' of line, would one trench work by having the line go out, and then double back with a foot or two of soil between(return line on bottom for rising heat)? Basically 'doubling up' the amount of line in the trench...

We looked into this in the Texas Coastal Bend and learned ground temperature (sand) dropped to 75°F at 24" depth but increased after that. Much below that got into ground water and digging requires an active high-capacity trash pump.

So... where is the part where you show the system? It seems like this was a really good sales pitch but there wasn't really a diagram or video of the system in action. Is there another video that follows up to this one?

Great idea , I heat my house using 2. .50 gallon electric hot water heaters with heat pumps using a open system .with radiant floor heat .if I isolated the radiant floor system and pipe it to the under ground loop to cool .my floor for the exchanger do you think that would work or am I better off using the radiator and fan. THANKS AGAIN FOR THE IDEA

What would it take further on down the road to tie a cheapo electric heat pump into your geothermal loop so that you could use it in the winter for heat

If you combined this with a solar water heater array on the roof, you could possibly have everything covered. Ground AC in the summer, Roof heat in the winter, roof heat for your hot water supply, and a peltier (thermoelectric) array that uses both to generate power for your remaining electricity needs!

We use this technology to warm our houses, it is able to bump the water temp up, then the rest it heated up traditional, so the gap it less in heating, 25c to 60c rather than 15c to 60c.

Put one in 2 years ago in my wood shop works well. Well be putting in another run for my house using 300 ft x 11/4 160 psi and 3/4 ×100 ft 160 psi to make a 200 ft run there and back , it hard to beat at 100 watts or less and you can just use water and use compress air to blow it out for the winter and you only have to blow enough out to account for where it comes up and down from ten ft .the water 10 ft down won t freeze .

lets see if i understand this. so the pump pumps the water/washer fluid from underground threw the radiator and the fan blows on the radiator thus producing cool air? so the stronger the fan the better for filling a room?

Dual 12 volt car fan! Depending on flow, you could also use 12 volt water pump. Methanol water mix to prevent freezing.

Do you have a material list for this? amd any information like a template? Thanks

So i live a in tropical country and im looking for a solution like this. Here is normal to have a undreground water reservoir 10 ft deep and can hold 8 m3 of water. do you think this will work with the lines on the button of the reservoir?

I am building a houseboat it is going to be in deep water can I use the geothermal air conditioning that you're talking about on this boat by dropping to down into the colder water

Could you just hook it up with the central heating system so cool water flows through all the radiators of the house. Maybe with an additional heat exchanger in between to keep the liquids separated?

Could you please do a follow up video to this showing exactly where everything is placed where does the end of the water hose go into where does the pump go where do you hook the or the radiator up to please thank you

Thanks for the video can you pls share what fittings you use to connect the radiator to the pipe

I have been trying to think of a way to do this for years I had some things figured out on my own but the radiator and the water pump thing great idea great I thank you so much for pulling this idea all together in my head I will be starting on it in the spring.

Any kind of calculation, project examples or empirical measurements about this theme?

Few questions: how long of a trench you need or how many square feet of trench? How do you arrange the tube in the trench? How do you use this system in a house? You would need a dedicated room that would spread the cooler air throughout the house.

is there a way i cab calculate soil temperature with the avarage yearly temperature or a world map of the soil temperature (at around 5m deep maby) i really want to try this out and think that it would be effective no matter what the soil temperature since it will mainly be different than the air temperature

Would this work well if planted below a pole barn/garage slab before barn is built? Probably around a 1200sqft slab. It would In turn be constantly shaded so I would assume it would stay cooler. And possibly split to two radiator fan setups? One on each end. Thoughts?

I am planning on doing this only using vertical diy shafts, probably a dozen 30-40 ft deep. I'd like to also find a way to either or both run it into radiant slab and a heat ex-changer into the central A/C system.. Figuring how to make it all work automatically will be the most difficult part in my mind. Awesome video!!

Man you sound like you can sell ice to an Eskimo. Love it.

Am in Canada on clay soil. We are going to try this to heat and cool a 28'x36' garage. My goal is 10'C in winter and 10'C less than. summer hottest days. So am going to run a fan high up on the ceiling in summer and water lines in the slab for winter. Knowing that friction loss is directly related to pipe size am thinking of using 1" for everything so the pump won't work as hard. Thanks for this video.

3rd year on my system. 600 ft long 8 ft deep 2- 1 inch lines spaced 16 inches apart. Keeps my garage 40x40 12ft ceiling pretty comfortable in summer. In the winter it stays about 40 deg.f at night and warms a bit during the day. I run plain water in it and haven't had any issues. I fixed it with a condesation pan , i have collected water from it but not as much as i thought it would. I'm using a 20x24 radiator for a wood boiler. Oh, it took me 40hrs to dig (3 days in the hot seat ,sun up till sun down)😂

Do you have any working prototype for this system, i would love to build this for my farm house

My only critique. Using low grade heat transfer in summer, the radiator may not get cool enough to dehumidify the air in the same way that a compressor driven system would. I think that someone should take an air conditioner and add a liquid to liquid heat exchanger after the condenser coil for additional cooling from the ground water. In this way, the condenser can blow of some heat to the outside air and then get a boost of cooling from the ground water loop.

Where do you locate an ugly radiator in the house and what about the interface where the pipes come to the surface where the air temp is very hot ( 40C possible where i live ) ?

I had an idea for a variation of what you are showing. Here in the South West Pro-Panel metal roofs are common, and I thought that just putting sheet material over the tops of the Propanel would make ready made channels that air could be circulated through, sun in the winter, and night sky in the summer. It utilizes existing roof space. It would work for a garage or green house or thermal mass in a crawlspace. That way like you mentioned you don't have to worry about mold, or Radon or filling up with water. It could be installed in new home construction. I really like your variation of space heating.

Same concept can work for heating the greenhouse, but the water lines are placed under the greenhouse and pumped with solar hot water during the summer.

I love the idea and have wanted to do it for a couple years but live in the southern US ground temp 12-20 ft down is 72-75 f and even a well system will only get you down to 65 - 68 range (20 c ) not sure if the temp difference would be enough to cool in the summer but seems perfect for the north

My driveway is always shaded. So it's constantly icy in the winter. Pita. I wonder if I can just run pipes under it and then run this she pipes deep in the ground. If it doesn't work then I'll add a boiler.

As there are few diagram, I'm trying to visual the radiator connection. I'm assuming that out connection (to the lower tube) is at the bottom of the radiator and the connection to the return (upper tube) is at the upper radiator connection. Am I right?

Hi Simple Tek, just wanted to drop you a line and express my thanks and appreciation for this excellent video. Very simple, straight forward yet detailed enough to provide all the information one would need. Keep up the great work. Being a fellow Canadian, I especially appreciate your content as it is climate similar to the areas where I would build. All the best to you, HDH [: { ].

I live 30ft from a spring feed lake. This is tempting. In my situation I'd only need say 100ft of pipe. The lake water is always pretty damn cold 🤙

Is there a downside to layering the tubing for separate systems such as setting tubing at 8ft then using another set of tubing at 7ft for separate systems? I only ask for the people with limited land that want more than 1 air system.

Thank you for this video-- interesting and helpful! One question though. It seems like this works both for heating and cooling-- you're taking advantage of below-ground temps that are closer to what you want in your own space. But there were a few times in video-- and in comments-- where heat pumps are mentioned. Are these something different? Thanks again

Can you dig a 100-foot trench and run the 400ft pipe in a coil action back and forth?

What is the min space this could work with? Could raised garden beds help max out a smaller lot?

I am using a 8x10 green house. I was going to dig a 7x7 pit 6ft deep run water line to there will this work?

8 to 10 feet is a considerable depth to be running a good length of trench. Especially if your ideal conditions for burial are in sand. Sand requires sloping outwards at a specific gradient from your trench base at that depth, or rated shoring, to ensure it will not collapse. I would not recommend anybody go that deep without shoring, especially in loose soil.