Zero-Dollar AC System Looks Funny But Works Well

Basement-cooled AC

Summer is here and with summer comes hot days. You probably know that us humans get uncomfortable if the temperature rises too much. Sure, we could turn on the loud and inefficient window AC unit and try to stay mildly comfortable while the electric company pick-pockets pennies from our change purse, but what is the fun in that? [Fran] had a better idea.

He noticed that his basement was always in the upper 50°F range regardless of how hot it was outside. He wanted the cool basement air to reside upstairs in the living area. After thinking long and hard about it he decided that a box fan and two long, skinny cardboard boxes assembled together would be enough to move the required amount of air. Both the fan and boxes were kicking around the house so was no cost and no risk to try this out.

The now one-unit assembly sits on the stairs and blows the cool air from the floor of the basement up the stairwell and into the house. For this to work the door leading to the basement must be open. At this point the system worked somewhat well but [Fran] wanted more airflow. Air was being blown into the house from the basement but the air already in the house didn’t have anywhere to go. [Fran] decided to open the attic hatch to let the air escape which resulted in a big improvement in airflow and decrease in living area temperature.

As funny or low-cost as this may look, [Fran] reports some impressive numbers, a reduction of 11 Kwh/day, which is 50% of his electrical usage during the summer months. He claims to have not used his wall-mounted AC in several years because this cooling system works so well.

119 thoughts on “Zero-Dollar AC System Looks Funny But Works Well

    1. One thing about underground facilities, the deeper they are the easier it is to control HVAC. A few feet down and you have a steady 70° F all year round. But if you go too deep you have to deal with geothermal energy. That’s good for heating water pipes though. Old USAF-ICBM missile silos for sale are great for HVAC costs.

      The richest man in Connecticut has a mansion atop a north-central CT mountain just like this. It is a Hollywood-style backdrop-esque mansion on top of a vast underground home complete with every creature comfort imaginable. His HVAC bill is very low. The faux-house looks very real to the eye but nothing is in there except storage and a stairwell to the residential facility.

      1. Mmm.. people have been saying slashdot has been going down for years. I think this time it is true. After the beta fiasco started all that seems left are astroturfers and old out of touch people.

        Lamentation always seems to be off topic.

        1. I left Slashdot because of the beta disaster, now I get my news and comments from SoylentNews It’s just starting out so the community is still small, but a lot of the interesting and insightful commenter’s came over from Slashdot. And there’s not many trolls… Yet. ;-)

    1. Unless this guy is in northern Canada I’m calling bunkis on his claim that his basement is in the 50F range during the summer months. Having spent most of my life prior to the last 10 years living in Michigan the basement temperatures in the house I lived in would average 75F during the summer without AC in a single story 3 bedroom ranch. Many of the farm houses I visited for work would average about the same despite having cement or dirt floors and walls up to 2 foot thick made of field stone.

      1. @billthewelder – I read through the website where OP was quoting from about a guy named “Fran” from Waterbury Connecticut:

        I can’t find where Fran says his basement was ” 50F range during the summer months”. If the OP said that then he must have misquoted. Fran said his north facing wall A/C can bring the entire house to 50F in short order.

        CT is not far from Canada. Also if you look at the actual home you see it’s a (maybe 2-bedroom) raised-ranch built in late 1960’s early 70’s. It must have a finished basement and an unfinished attic. That means that not only is it a masonry foundation (you can see in picture) but the walls are covered with drywall and most likely has fiberglass (or foam) insulation behind them and up in the floor joists overhead. It’s also built into a small hill. CT is mostly shale and trap-rock. So no wonder why his basement is so cool in summer months. All that cool heavy air settles down through the stairwell and other openings at night. It remains there for awhile due to this insulated chamber. His basement garage must be separated by a masonry or sheetrock firewall (with possible a wood or metal access door) which prevents too much air-leakage through the garage.

        So I don’t think this is “bunkis” at all.

        He also has a “white roof” which one side is south facing – perfect for solar cells..

  1. This is great. I love seeing people derive real solutions to real problems. My grandad lived on a farm and built an air exchange syatem to cycle air from the basement to the top floor by an outside shaft, he had no A/C.

    1. no need to push

      I do the same thing every morning, I open the window to let the cold air in, then I open the door to the stairway (4 story building, windows on top floor open) and escaping hot air at the top creates negative pressure sucking air out of my flat (filling it with colder air from the outside)

  2. or another way to do this is the use of a whole house fan. you just have to figure out which doors and windows need to be opened or closed for it to work correctly for your particular house/apt

    1. This works much better on houses that were constructed to take advantage of the whole house fan. If your house was constructed between the advent of air residential electrical service and the advent of air conditioning, this is very likely the case.

      Houses build with central A/C tend to work not nearly so well, at least not without some tweaking — as you have discovered.

  3. This is a traditional solution and works very well. We rely on a timer/sensor fan system (Arduino, of course) I’ve built that pumps cool air in at night then shuts off the fans once the outside temperature starts to rise again. That’s way more tech than is needed (but consider where you’re reading this) – for years a simple timer sufficed. On at about 8 pm off again at 6 am – or you can just do it manually. Saves us a couple of hundred dollars in electricity every year.

    Of course as the real summer swelter (I live in the Midwest) comes on you have to retreat to the air conditioning, but that season is shortened – this year has been cool so we’ve only run the A/C a few days.

    1. You should add some water barrels to your system. If it is cool at night you could even build some cheap solar panels and run them at night to dump heat and in the winter run the pump in day to warm up your thermal mass.

  4. Our furnace’s blower went out earlier this year. Our trick? Pop the cover and put a box fan up against it until it could get repaired. The box fan was pulling cool air from the basement straight into the duct work for the whole house. Only thing after that was closing the basement vents.
    If your blower motor is still OK, you should be able to do the same thing (may have to override a safety switch to have the panel open).

    1. @Paul – Good idea. I was wondering the same thing as my central A/C blower died years ago. But does the box fan have enough strength to fill the entire ductwork? I guess shutting off the basement vents will help immensely huh? I only have an attic door. I guess I could prop it open for the top-air-escape?

    2. One other trick that I tried was to use the blower on the furnace to pump cool outside air into the house at night. If you block off the return vent in a couple of rooms, open the windows, and close the doors, the air ducted into those rooms via the heating system has to leave the building through the open window. This means replacement air has to enter the house from another source due to air being pulled through the remaining return air ducts. Open a window in the room you want to cool and you’re all set. Works best if your house is well sealed.

      If I had a spare furnace blower, I’d duct it to a window and possibly setup a control system for it. I find that I don’t need cooling during the day, just getting the hot air out of the house at night would create more than enough thermal mass to keep the place cool for most of the day.

  5. The problem is people who dont have basement.. also who has can spend there most time in hot months, and even older people got houses fresh all year with house painted with the right colors to repeal hot.

    But the bigger problem i see, is specially for those who live in an apartment, when there is hot outhere, for more windows you open you only get hot air, even it moves it still hot.

    1. @Dr_Lion – If you don’t have a basement, get a large cardboard box and line it with Styrofoam from Lowes or Home Depot. Get some 1-gallon plastic milk jugs with water and freeze them in your freezer. Line them up in the back of your box. Use the OP’s same box fan idea just position it somewhere in the center of your basement-less house. The ice should last all day. Simply replace the jugs periodically. Get a bunch of jugs as backups. Make an access flap on the back of your box so you don’t have to disturb the box fan every time. I’m wondering if this should be a rear blower (pusher) through the open box or a front blower from a closed box. I think the former will work better than the later. (Maybe some HaD tinkering can make this idea better?)

      This would be an excellent mobile A/C for your car if you used a $8 Home Depot Styrofoam cooler, an $12 Walmart 12 volt fan, and 2 pieces of PVC elbow joints ($2/each)as air-directors. The 12 volt fan would push air through a cutout on the top and blow out through the side elbow joints. Same ice jug method.

        1. I didn’t need math to assume that multiple frozen ice jugs should last pretty long inside an insulated enclosure. By all day I meant for as long as the sun is up baking your house. That’s probably several hours up until sunset. And we are dealing with more than one frozen jug. And even when they start to thaw out the water will still be pretty cold for a while longer. All this is seat of the pants guess work. Just a fun experiment.

          1. The cost of freezing the water will be high – at least as high as running an A/C unit for the same amount of cooling.

            At the same time, the heat generated by the freezer will increase the temperature more than the ice will cool it.

            Thermodynamics – a law you can’t break no matter how keen you are.

          2. Old reply is old. Standard responses include: if the apartment is plenty cool during the night the extra heat from freezing the jugs is not an issue. The per day cost of freezing may be higher than the per day operating cost of an A/C unit. But if you already have jugs and fans You might as well try it before buying an A/C unit.

        2. sonofthunderboanerges is right; you don’t need math if you’ve ever experienced anything with a gallon jug of ice. But if you want a smidgen:

          The energy required to melt and heat a gallon of ice to 20 degrees C is about ~ 1600 Watt hours. ((latent heat of fusion of water)*(1 gallon)*(density of water)+(specific heat of water)*(1 gallon)*(density of water)*(20 Celsius)), thanks wolframalpha.

          The power used by a small window AC unit is ~500 Watts, with maybe 100W used to drive the fan. So ~400W for cooling. Small AC units have an efficiency rating (cooling rate / power consumption) of less than one, but we can take it to be 1 (in favor of the AC unit). So over 8 hours, we can expect the AC unit to cool about 8hours*400W = 3200 Watt hours of heat.

          If we take two gallon jugs as in the suggestion, they will ALSO soak up 3200 Watt hours of heat. This easily puts this system in the realm of plausibility (and not the realm of “Bwahahah learn physics/math n00b” that you claim.).

          1. @Wes – And I was going for at least 4-gallons of ice. That’s 4 jugs. And you have to take into consideration that the Styrofoam insulation and the PVC plastic surrounding the ice is in affect stretching out the thaw time. Also the box fan is passing air over the jugs slightly reducing the thawing effect. But the air is not stopping it only slowing it down. Anyway 20° C is 68° F (here in USA) and that is not hot water yet. 68° F is still pretty comfortable (but not as much as 32° F – 0° C). But that won’t happen until around sunset when the house is already cooler from ambient outside temperatures (e.g. house with average insulation). Also you need to take into effect our body perspiration. That’s the reason why box-fans make us feel so cool even when its only blowing warm air at us. I think scientist call this “wind chill effect”.

            I’ve not used wolframalpha yet. I still can’t understand why I would use it over Google. I’m a Master-Googler and can’t use anything else. I’m disappointed that they took out “+” and “near”. But “-” still works. I particularly like &num=100 you can put on the end of a Google search string URL. It allows 100 hits to be shown without any MORE or NEXT at the bottom. That is if there is no more than 100 hits that is.

          2. Yes but the heat of freezing the water will be put into your living space. Unless you keep your freezer somewhere other than your kitchen. Air conditioning units are made to exchange heat from indoors, to outside. It really all boils down to where the condenser coils are located which is the more efficient method.

          1. @Alex U. – GOOD ANSWER!!! (LOL) Also you could shoplift the Harbor Freight solar array too. :-)

            @Luke – Am I missing something here? How does my refrigerator work any harder to freeze some water jugs in my freezer compartment? I’m thinking the fridge will work at the same effort it did with nothing at all in it. Yes if I change the freezer dial to COLDER then I agree. But if I’m making hard ice cubes within 2-3 hours and the setting is just fine for that, how is it working any harder to freeze some extra jugs? OK maybe they will take longer to freeze (several hours), but I can wait. I’ll do it the night before or sneak by my job (or neighbor’s house) and use their fridge… :-)

          2. @sonofthunderboanerges
            You are placing jugs with relatively warm (ie not frozen) water into the freezer. This warms up the freezer. The heat energy from the water goes into the freezer and the freezer must dissipate it (into your house so freeze the water at night when it is cool anyway). Basically the freezer is a machine which takes heat from the inside of it and moves it to the outside of itself.

          3. @sudobash1 – I’m going out on a limb here and say that my cold tap water (from city water dept) runs at about 20° C or 68° F + or – a few degrees – or maybe even cooler. It is cool because the pipes are all underground (like our electricity SHOULD BE). Somehow I do not think my water jugs are imparting that much thermal energy into the compartment making the compressed evaporator coils on the back work any harder.

            Anyway a young African kid posited a new theory to a science professor not to long ago and now the scientific world is baffled as they proved it empirically in the lab. The kid asked: “How come when I put a pan of very hot water and a pan of very cold water in my freezer, the hot water ALWAYS freezes first?” The professor said that just can’t be true and the kid must be mistaken (like a typical scientist-skeptic). The professor tried it and found out the kid was right. Try it yourself today.

            Who can explain this convincingly? Scientists presently CAN NOT (convincingly that is).

          4. @sonofthunderboanerges
            … your water jugs are imparting exactly the same amount of thermal energy into your compartment as you are putting into them when you unfreeze them. This will most definitely make your evaporator coils work harder. I believe that most freezers are either ON or OFF, i.e. the evaporator coils turn on when the internal temp rises above some preset value, and then turn off when the temp goes back below some preset value (which is probably lower than the first). If you put the jugs in your freezer, the coils have to extract that heat, and they will dump it (along with the heat they create due to inefficiencies and the second law of thermodynamics) in the room that they occupy. If you put your freezer in a perfectly insulated box and put the jugs inside the freezer, and then when they were frozen put them outside the freezer (but still inside the box), the box temperature will be significantly higher (after they have melted) than if you had just left the jugs outside the freezer.

            For the next part, what you’re referring to is known as the Mpemba effect. He didn’t actually put forward a theory, he put forward an observation (pretty important difference), and there are several theories as to the cause, the prevailing one being that it is due to a combination of supercooling and convection effects. Why is this unconvincing for you? Also, this was almost 50 years ago, so not sure how you define “long” (home freezers have only been around for ~100 years).

            If you are interested, the thermal energy lost freezing 100ml 35C water is 48.1KJ, while freezing 5C water means losing 35.5KJ, which is 25% less.

          5. @sonofthunderboanerges, are you a troll? Seriously. Certain ranges of warmer water sometimes freezes faster because, in heating the water, dissolved gasses that otherwise slow the process down are released. This has been a known thing for a very, very long time. No african kid involved in the discovery either.

            “Who can explain this convincingly? Scientists presently CAN NOT (convincingly that is).”

            Who am I kidding, you are a troll that probably doesn’t even know you are. It is kinda like those ancient alien tv programs. Even when they get contrary evidence they say they aren’t convinced, pull a no true scottsman out of their nether regions and smugly march on.

            Your cooling idea doesn’t work any more efficiently than an air conditioner. It also won’t work for very long at all. It takes massive, massive amounts of energy to heat or cool a space. Even the article states 11kwh. How many jugs of water would it take to do that? Now think about how much it would cost to freeze them.

            Speaking of energy, it is probably best just to not waste any more time with this. You can think of it this way, if your idea is better than literally any other commercial alternative, you could market it and retire with millions in the bank within a decade. So go ahead, get rich and laugh at all us naysayers. I shall await your invention at the nearest home improvement store.

          6. @Brian Benchoff Not a good idea. I have my workshop in my garage so there’s no room in there for a freezer, deep, or otherwise. Although hey if you’ve a spare $50,000 I’ll gladly build myself a detached workshop, then I’ll have room in the garage for your not so good of an idea.

          7. @BNBN – Thank you for your clarifications. 1969 is not a long time ago for me. But I understand your corrections. Here is the African kid story (but people have been aware of it since ancient times):

            @ddfelaee – There is a number of “probable” explanations of the Mqemba Effect but none are conclusive yet. You need to do empirical experiments to verify the effect yourself AND whether or not the cost benefit is viable enough to proceed freezing jugs in your fridge. Brian’s idea of a deep freezer in garage was cool! The OP does have a COSTCO just outside of his town on the east end. Or the HaD tinkerer could gut/cannibalize some thrift-store Peltier Effect coolers and use them as the cooling elements instead of frozen jugs in this scenario. Of course it would involve more electricity used besides the box fan. I wonder what the cost benefit analysis on that would show us?

  6. Where does the basement get its air supply from? (The warm air from the rooms above or from outside?) And what does he do with the moisture that condenses in the basement from that air?

    1. Basements are usually insulated with fiber insulation in the ceiling and masonry wall foundation buried about 8-10′ below surface. So when all the house’s cool air from the night before settles down there (as cold air sinks and hot air rises), the basement gets pretty cool. Conversely the attic gets wicked hot. So an attic exhaust fan is a good idea too. A push/pull configuration would be ideal. But unfortunately this idea will last only as long as you don’t have a heat spell. Then there is no cool nights to recharge it.

      1. And yes I think the OP did not mention his basement walls are pretty moist from condensation. He needs to go downstairs in the middle of the day and feel the walls while his cooling system is running. You can fix this by having the basement done over by those basement contractors on CT TV.

        1. So I was thinking. Where I live the condensation might make this work even better, but then you’d better manage all that water in the basement or your basement is going to be nice and cool and moldy like a wet cave. Then your mom won’t come downstairs.

  7. Think about this: When was the last time you saw a large 3-bladed box fan?

    Honestly, they haven’t made those since the 1970s or so – the only time I have ever seen one has been at an antique store or an estate sale. That fan dates from an era when “durable goods” really meant just that…

    Anyhow – this is a great solution to cooling, but it would never fly here in Arizona, unless you were one of the really lucky ones to have a basement (and it better be a deep basement at that!). Right now it is almost 6am, and 95 degrees F out. That said, this summer has been pretty mild until only this past week or so – compared to other years I think. But it’s beginning to warm up – sooner or later, it won’t be much longer before 100+ temps through the night and early morning hours will be a regular thing.

    I guess I’ll need to stick with my A/C…

    1. @cr0sh – What you need in Arizona is what’s called a “swamp cooler”. You can make those yourself. They are not hard to build. They introduce a lot of humidity but that’s what you need there. Here in Connecticut a swamp cooler would be a humidity nightmare for us. One thing we don’t need is humidity in CT.

      1. @sonofthunderblahblah – anyone that lives in Arizona is well away of what a swamp cooler is. Evaporator cooling is tied to the dew point, and even the best (and that excludes your home made version) can only drop the temperature to about 12-18 degrees (Fahrenheit) above the dewpoint. Current dewpoint in Phoenix is 69, so the average swamp cooler would struggle to get the indoor temperature below 85 – hence the need for real Air Conditioning. Colorado on the other hand currently has a dewpoint of 56 – so our house is currently being cooled by a central swamp cooler (which switches over to central ac when the dewpoint rises above 60).

  8. OK I see this idea has merit. But why pay CL&P (Connecticut Like an Power) or UI (United Illuminating) one single dime? If you have about $200 bucks to invest, go to Harbor Freight (a hardware store chain franchise) and get yourself a $145 12-volt solar array and a 12v-110VAC inverter from them too. You can power your box fan with this. Just aim the array south away from tree shade. Let that hot sun that’s baking your house also pay some of your electric bill too while cooling it. While your at it stop by Walmart and pick up some car window tint rolls for about $8-19 bucks and cover your south facing windows in tint plastic. It can be stapled up and doesn’t have to be permanent. However, if your patient you could make it permanent as home builders now install this in new homes. It doesn’t look that bad too. It will stop IR heat energy getting in but not all visible light. You can see out but no one can see inside (easily).

    1. Because the HF solar kit is complete crap. It’s really a 25 watt setup not the claimed 45 watts. And it’s the crappiest solar panels made. after you put the inverter on it you will not be able to power the fan.

      1. [fartface and pcf11] – No I do not have any of this. My central A/C blower fan crapped out and I just use window A/C and box fans (and electric heaters in winter). My electric bill is astronomical here in Connecticut as the OP from Waterbury CT will tell you. We probably have the worse DPUC (Dept of Public Utilities Control) in USA. Our utilities monopoly NU (Northeast Utilities) are all a bunch of crooks. Most states have evolved to underground power lines to help mitigate wind damage. Not CT. They just “grin and bear it” during hurricanes and such and ask DPUC for rate hikes up the wahzoo to compensate for all of the weather related power failures here. We are one of the richest state with the poorest people too. They really screw the middle-class here. People are moving to the South as they hate it here so much. Bush is rumored to be moving back here soon too. That must explain how crooked CT is (LOL)

        You may be right about the cost benefit analysis between the purchase price of a HF solar array ($145 on sale), an inverter, and the cost of running a box fan on high for 24 x 7. I was just brainstorming like I like to do on HaD. I did not know that the HF array was a POS. I never used one. I thought that was pretty cheap. I’ve never heard of solar cell degradation. They are basically made of sand. How can they go bad? And how does one know a HF solar array is 25w and not 45W as advertised.

        I’ve only had a little bad luck with their $5 DVM and their $40 IR laser heat detector. They both still work but they got a little crappy after awhile. I like to browse at HF as they have so many unique things to “think” about buying and they give away so much free stuff too. I still have stuff in my garage I haven’t even used yet.

        Anyway solar is always a good idea. Here in CT they offer to set your house up with an array for FREE through some state grants. But for the life of me I can’t understand why you need to fill out a credit app and do a credit check if it’s all free. And as usual the crooks at NU will not allow you to get off the grid with it and pay you for reverse power. You still get nailed pretty bad EVEN if you have the solar array. These crooks want your money no matter what they have to do to get it. And their cronies in state government are working with them under the table. This is definitely a BUSH state!

          1. @Galane – So what? CT is a democrat state as it’s governor is one too. I don’t see how the President effects DPUC rates. Most of the corrupt officials in CT are GOP. The very guy running for CT GOV now (a Republican) was one of the crooks that stole $9B USD from Iraqi CPA back after the OEF War with Paul Bremer.

        1. I have amorphous solar panels similar to Harbor Freight’s offerings running a water pump in the pond in my garden. Let me tell you they don’t last forever. Mine have been out there for 3 years now and they are showing some wear and tear. I do not know what is happening to them exactly but I’d say that they are oxidizing by the looks of them.

          I’ve driven through Connecticut enough to have developed some strong feelings against it myself. Worst drivers I’ve ever seen. I’ve seen some pretty bad driving too. But Connecticut is way out in front when it comes to douche bag driving. Yield, and merge mean something entirely different in CT.

          1. @pcf11 – Yes I’ve heard about those amorphous solar panels. Is that the Nanosolar cells? If so then yes they are really DIFFERENT than the standard glass versions. They also were driven out of business lately – they claim due to Chines knockoffs. I think it is something else.

            You’re right about CT Drivers and yield signs. It appears we have no concept of merging. And we have too many hot-heads just waiting to do road-rage too. However, MASSACHUSSETS drivers fly through our state like maniacs thinking we have no reciprocal law enforcement agreements with Boston. NY drivers used to be insane too but lately I’ve noticed more respect for our traffic laws. And they don’t lay on the horns too much these days either. I guess they got tired of the NYC stereotypes “forget-abo-it!” :-)

    2. You could run a box fan on high 24/7 for 455 days for $200 worth of power company electricity. Just plug it in and let ‘er rip! There are practical reasons why renewables haven’t caught on you know? Well, you’re pushing them so perhaps you don’t?

      BTW the HF $200 panel only produces 45W and I calculated at 165 Watts. So you’d need about 4 panels to even begin to get close to the kind of power consumption I figured out. Now you’re up to 1,820 days before you break even. In that amount of time you are going to lose storage cells so you have to add their cost. It could easily stretch out to 10 years before you begin to break even, and start putting pennies into your pocket.

      But after that it’s all gravy I suppose! You’d better keep your health insurance paid up just to help make sure you live that long. Solar is great until you begin to do the math.

        1. I’ll be 50 in a few months so I don’t really care. I’ve had my fun, and I’m still having it too. I’m going to live it up for as long as I can. The climate has always changed on this planet anyways, with, or without us. Heck if the climate didn’t change we wouldn’t even be here. Climate change is what made us sentient beings. As far as exploiting fossil fuels goes it is the greatest thing that has ever happened to us too. It was not so long ago that most folks never made it more than 30 miles from where they were born before they died. You can’t even grasp a world like that, and for that you should be ecstatic too.

  9. For some reason I’m now thinking about those termites who build mounds. Their mounds remarkable architecture keeps the temperature almost constant. Precise temperature control is needed to maintain their fungal gardens, which breakdown wood, their food source.

    I wonder if anyone has created iterative models of the air flows required to make that happen over a wide external temperature range. The structure would probably look very weird indeed if scaled up to human sizes.

    1. @Truth – It’s called “BIOMIMETIC ARCHITECTURE”. They are doing it at The Eastgate Centre in Harare, Zimbabwe (Africa). You can GOOGLE it. They have no HVAC in the building. Makes one wonder about how Natural Selection can explain this unusual built-in (instinctual) behavior among lowly insects.

  10. Properly built homes take advantage of this. It’s the poorly engineered crap that has been built over the past 20 years that dont. Open the small basement windows, then open the upstairs windows. house is nice and cool due to air convection. Sadly most modern homes are designed by college dropouts, and built to be as cheaply built as possible.

  11. Okay, so I’ve seen a similar solution in a local 1800’s mansion. This building had a large underground (aka basement) area used for storage below the stairs at the front. Once the vents were opened to the house and the upper windows were opened, the whole house was cooled off to a bearable temperature (no insulation in those days).

    I’ve always thought cooling a home would be most efficient using several excavated shafts directly down, or at an angle outwards from a house. Line those with brick or even plastic ridged drain pipes and vent or “V” the holes such that air can be pulled up through the house. Adding the fan would make this work very efficiently… The fan could even be solar powered to mostly cut out the electric company.
    My only concerns would be the amount of mold or fungus growing in the moist, dark environment created by such a construction.

      1. Here in CT we do have a higher than national average of RADON. The OP’s county (New Haven) is pretty high. My county (HARTFORD) is medium-high. But we do have radon mitigation contractors who can mitigate radon in your home for a fee. The kits are cheap and you can get them from Home Depot or Lowes.

        I would not depend on using this system to “ventilate” toward my living space. You need to ventilate OUTSIDE before doing this. But that would defeat the purpose I think. I’ve seen these “ventilators” here in my town. I didn’t know what they were until I googled it.


  12. if you don’t have a basement, probably you could dig in a thicker pipe in the ground around the house, and get the outside air through it into the house via fans. depending the location you could get chill air constantly even just in 3ft depth, or so, i guess.
    it’s helluva hard work to do, but it delivers you “geothermic” cold for free.

    1. Please show the basic math that you mis-used to come to your deduction. The pipes would have to be HUUUUUGGGGE in order to approximate the volume of air storage that even a small basement has. Once you use up the stored cool air, the entire cooling effect is finished, and you’re just recycling the outside air at whatever high temperature it is at the moment.

      1. Bullshit. This is a method that have been used for ages and yes, it works very well.

        Hint: keep the other end of the pipe open and air will enter, be cooled and exit cool in the house. That works the other way too, dig down deep enough and one can warm the inlet air during cold winters.

      2. The pipes are a heat exchanger the earth is the storage medium, just like the basement walls and floor are the heat exchanger, the earth the storage medium Yes the pipes will have to be large to insure a sufficient air flow.

    2. @bat – I was going “huh?” when I started reading this. Then I saw “geothermal” and went “oh ok I get it”. Yes GT is a really unique method of heating and cooling. I ‘ve seen houses in Connecticut (very rich homes) that have it. They have to run the pipes pretty deep to get the hot stuff. However I guess you could do some cooling to with buried very large diameter ABS/PVC conduits. I think 3-feet deep is a little too shallow. You might need to bury them a little more than that to get effective cooling.

      Have you ever tried to dig a 3-foot deep trench? It’s grueling work for lazy-people like me. Imagine if I had to do it for a large diameter conduit at say 6-feet down. If I had a backhoe I might consider it as valid idea. If I did that I might as well dig me an underground shelter like a 1960’s bomb shelter (or 19th century root cellar). Line it with cinder blocks. It would be the coolest (temperature-wise) place too. You could call it your “man cave” literally. :-)

      1. Long relatively-shallow trenches with a large-diameter air duct buried in it that runs out a hundred feet or more from a building then loops back into it in order to use the ground’s thermal mass to moderate the temperature of the air (either warming or cooling it) are called “ground source” systems. A lot of them have been built, though most ground source systems use heat exchangers with a water/glycol mix circulated in small-diameter pipes with a pump. That also works great with a moderately-large pond or lake (just put the exchanger in the lake).

        Ground source air ducts can induce their own draft using baffles on the ducts (no fan needed if designed well) and act to either warm or cool the air depending on the season (since the ground temperature is mostly stable at these depths).

        Systems that tap true “geothermal” energy (which is only hot) generally go much deeper and use smaller pipes (acting as heat exchangers rather than heating the air used in the house directly).

        “Ground source” and “geothermal” systems are completely different technologies using completely different energy sources, but since both are generally underground the terms are often used interchangably which can cause some confusion.

  13. Works BUT watch the humidity.
    It’s easy to get mold started (spores are eveywhere, but they don’t get real excited til you have moisture available. Pulling warm humid air into a cool basement is a good way to condense moisture on the surfaces. Ditto pulling air into the house through a buried pipe.

    It’s doable, but you have to pay attention.

    We had one attic vent — so I took a computer box fan and a length of stovepipe run the whole length of the attic, ran the exhaust out half the vent and off to the side, so the incoming air then traveled the length of the attic, before being sucked into the pipe and pulled out again. Dropped the attic temperature by 40F on hot days. Just 40 cubic feet a minute adds up when run through the hot hours.

    After we had to replace the old tar and gravel roof with a new one — “high emissivity” cool roof material — we had the same 40F decrease in internal temperature without the fan. (And with “cool roof” material you also have to think about condensation — same principle — water will condense on the high emissivity material because it’s radiating heat away to the nighttime sky just like the water you see condense on a parked car overnight, with the same issues — if outside air circulates through the car it gets damp inside; same for your attic, so a “cool roof” has to be insulated underneath the material).

    Not simple. Doable, with some basic stuff thought through.

  14. About 40 years ago, a guy from popular mechanics did a similar thing…in the evening, he would turn on a fan in ductwork that went out the window just above the ground to bring in the cooler air…your idea looks like less humidity brought in though.

  15. I’ve always thought “Gee, the air is so cooler in the basement than upstairs, if I could only get the cold air upstairs.” And now somebodies done it and it works, time to go to the Home Depot for some fans and ducts.

  16. Back before anyone had electricity buildings were designed with passive heating and cooling (and lighting) in mind, which explains many of their features (see links below).

    Then we got power and with it fans (and lights), then later HVAC. Design was no longer limited to the demands of the local climate so buildings could be hideously inefficient which often made them cheaper to build but energy being cheap made them easy to keep comfortable year-round.

    Now energy isn’t cheap anymore and barring any paradigm-shifting breakthroughs it’s only going to get more so. As a result, we’re having to start reassessing our design principles (or lack thereof) to boost energy/thermal performance as passively as possible (hence the increasing popularity of “passive solar design” in Architecture).

    So we find ourselves reinventing wheels that were invented 1000+ years ago. In that sense, classical architecture has much to teach.

    Two essays that explain the details far better than I could can be found at the links below, and are well-worth a read (especially by any aspiring hacker of built environments!).

    Both essays had been removed from the original site, so here’s the archived versions and no worries, they’re quick reads and IMO ought to be mandatory reading for Architecture students:
    Designing for a Sustainable Future:

    Seven Misunderstandings About Classical Architecture:

    1. @bubba gump – I assume you mean your live-in grown son? Just start a company in where you provide a service, lawn maintenance, newspaper delivery, PC repair, TV repair, grocery pickup/delivery etc. Then hire him to work for you as your apprentice. Give him an allowance for pay. That way everyone is happy. If you already have a full-time job then just do it after or before hours.

  17. You actually don’t need a basement, you just need a thermal battery aka a cold sink. In most areas of the world with deep enough soil, 6 feet below ground is about 65-70*F. Put some pipes filled with water 6 feet under ground and then route the water through radiant heat exchanging around the house. Most HVAC engineers will tell you that merely sitting under white roof and walls will drop your temps by 15 degrees below outside air temps during the summer. 85 degrees Is a lot more comfortable than 100!

  18. Oh, yeah. I looked into doing this several years ago, but didn’t pursue it because I talked to a fireman. If there’s a fire, it’ll actually speed the structure becoming fully involved amazingly fast, as it pushes the fire through the structure. He’s built a really efficient chimney, and all it needs is a fire. He’s added the blower.

  19. Too bad both simple solar thermal and simple geothermal methods aren’t employed more. Surely a simple reliable means to close the inlet of a solar chimney in the event of fire can be devised. What are the chances, now that the home is open to the roof vents the fan can be removed, with reducing the cooling, disregarding the danger in the event of a fire.

  20. I like this hack…
    Since I have central air, removed a filter cover door on my furnace (located in the basement), closed a safety switch and turn the furnace to blow (not cool to keep the compressor off and save some$) and same thing, cool air, just larger volume of it with less fuss!
    You can exchange cover door with air filter to keep those ducts clean and allow air flow, also basement floor needs to be open to allow for air circulation down into basement which would be under-pressured!

Leave a Reply

Please be kind and respectful to help make the comments section excellent. (Comment Policy)

This site uses Akismet to reduce spam. Learn how your comment data is processed.