Tag Archives: Cost

August has arrived

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Posted on August 4, 2013 by

Well, August is here and still no hole in the ground.  I didn’t post anything in July at all.  Mostly, I blame work.  There were a few weeks there where things got really crazy because I took on a big project that I should have declined.  I spent my evening computer time preparing “packets” to make it easier for contractors to work out their bids and that didn’t leave much time for the website.

Architectural Committee

I submitted my construction drawings (emailed pdfs) to my neighborhood’s architectural committee on June 24th (just before my last post).  I expected they would setup some sort of meeting so I could explain the drawings, so I offered to bring in the full size prints (one member of the committee told me he wanted prints instead of pdfs).  Instead of inviting me to a meeting, they just sent me some questions by email.

I expected questions about the direction the garage is facing.  The rules say the garage shouldn’t face the road, but because the road wraps around my property, it would have been difficult for me to face the garage away from the road, but I at least made sure it wasn’t facing the “circle” that my driveway comes off.  Unfortunately, you could still see the garage doors from the circle.  I talked about planting arborvitae to block the view and they were willing to accept that.

Rough landscape plan that we sent to the architectural committee

Rough landscape plan that we sent to the architectural committee

They did ask some questions about our landscaping plans.  They didn’t give much detail about the green roof and I think they were concerned that we planned to leave everything “natural” on the roof ;^).  Our answer of “park-like” seemed to satisfy.  They also expressed some concern about the back of the garage, which I admit is not the most attractive side of the house.  I promised to hide it as best as I could with trees and a bougainvillea vine.

The guardrail is drawn with straight lines, like wires, but I hope to use curved steel or aluminum tubes

The guardrail is drawn with straight lines, like wires, but I hope to use curved steel or aluminum tubes

The thing they were most concerned about was the safety rail.  Admittedly, the architect did make it look like stretched wires (very nautical), but I explained that my intent was more for horizontal steel rails that could be bent to follow the contours of the land.  They seemed to prefer horizontal rails to a vertical fence which may have appeared a bit like a palisade.  In the end, “safety rails” made it past the neighborhood association’s fence restrictions, but meant the building inspector would be much more interested in them.     They said that “before” they would approve, I would need to make sure those “guardrails” would pass inspection.

I contacted the inspector (who got back to me very quickly) and said that there was a rule for guard rails along a walking path next to a drop of more than 30 inches.  It is basically a 4 inch ball test.  Not sure how I missed it, but my wife found the exact wording of the rule on-line.

R 312 Guardrails are required on any exterior walking surface over 30in. from floor or grade. Openings in guards shall be designed such that a 4 in. ball will not pass through the guard at any point including open treads. Residential guards shall be 36 in. in height minimum from the finished floor or stairway nosing.

 

Horizontal rail, but the openings would fail the 4 inch ball test for guard rails next to a walking surface.

Horizontal rail, I would like this in black, but the relaxed openings would fail the 4 inch ball test for guard rails next to a walking surface.

If this rule is applied to my project, it means that I will actually need to go with a safety rail designed to meet that rule rather than the much cheaper and more open horizontal steel or aluminum fence that I liked.

On the other hand, the rule was intended for stair or balcony railings, so I am looking into if I could make a couple changes so the rule does not apply.  For instance, perhaps it will not apply if I move the rail back a couple feet from the edge.  I could plant bushes between the fence and the edge.  Or perhaps putting a flower bed along the fence, instead of a walking path would change things.

Bids?  Anyone?

Getting bids in summer (construction season) is no easy task.   It gets a lot harder when the house is complicated.  And the beautiful building weather we have had the past month has only made it harder.  I keep hoping for some really hot days so that these guys will want to be inside, even if it means filling out a quote.

I am sure I will put in a page about what I have learned, but I am not done learning yet.  Instead, I will give you my strategy and a few stories…

My strategy was to first put together a packet of information, and then phone each potential contractor for a conversation.  Many contractors ruled themselves out right away because they are not interested in new construction.

One told me that new construction requires you to work fast, but he would rather do a good job.  I have heard that line before and personally believe that a real pro can do both, but lets get back to the topic…

If they were interested, I could answer questions during the call with the information I had collected in the prepared packet (such as how many square feet of wall or how many fixtures).  I could also write down their questions and add the info to the packet.  For instance, the electrical packet included the electrical sheets from the construction drawings, as well as a spreadsheet where I had already gone thru and summed up the number of electrical outlets, light switches, 3 way switches, etc. so the contractor wouldn’t have to.

The strategy behind the packets was that contractors would get back to me more quickly if I made it easier for them.  It would also make the bids easier to compare if I provided the counts and areas.

But once I had a contractor (such as an electrician) on the phone, they often asked questions I had not thought of; such as which rooms should have switches controlling the bottom half of the outlets, or who my electricity supplier was (because one of the suppliers requires a separate meter for the electric HVAC stuff).  I then added this information to the packet so that all the bidders would have the same info.  After talking to 3 available contractors, collecting questions and polishing up my packet, I emailed the information out to each.

Then I made a mistake, I gave the contractors a couple weeks of “space”.  I think this may have sent a bad signal.  After the couple weeks, I emailed.  Again, too little too late.  A couple weeks after that, I called them again…  After a month of not responding to my emails, they mostly acted like the ball had been in my court the whole time.  Sure, they got my packet, sure they were interested.  Why did I wait a month to call and when did I want to get together to discuss it?

A couple of contractors have bothered to call me back and tell me that my project is too big for them.  I appreciate that because I can just move on to another contractor.  I know of at least one contractor who changed his mind and decided he was not up for it, but didn’t bother to tell me (I heard it thru the grape vine).  I want contractors who find it interesting and actually want to be a part of the project.

 

In one case, I did get a quote and filed it away while I waited for others.  After a few weeks, I took a closer look at it and compared it with the others.  I realized that it was totally inadequate in terms of detail.  It didn’t include the equipment rental costs and labor components that the other similar quotes had.  I called them up and they said they could give a more detailed quote if I was actually interested.  I said I was, which was why I had asked for the first quote, and they agreed to give it another try.  So now I wait again because they didn’t take my first request for a quote seriously.

In another case, I drove an hour to meet with the contractor (who made himself available after hours) to discuss what I needed.  I didn’t provide any information I had not already included in the email or phone calls.  He showed me some brochures that I had already seen on line.  After a while it became clear to me that it would be very easy for him to prepare the quote because he only had a few components to choose from and my needs made the final assembly pretty obvious.  So, I said something like, “I guess this quote should be pretty easy for you to put together, you didn’t need me to come in after all”, and he let slip “Yea, but I like to have people come in before I bother.  It shows me who is serious.”

In another case, during the initial phone call, I found the contractor did not have email.  Instead, he wanted me to drive out to the property (1 hour each way) to meet with him and “walk the site” with me before he could quote it.  His references were good, so I drove out and I spent over an hour with him.  I also gave him some print outs.  A couple weeks later when I called, he said he had sent the quote.  I checked and said he hadn’t.  I called again the next week and he said he was working 100 hrs a week, and hadn’t had time to quote it.  I said I would have to find someone else who had time for my project.  He said he did have time for working, just not for quoting.  I told him I needed the quote before I could hire him, so he said he would get it done that weekend…  Then a couple weeks after that I called him again (now six weeks since we had met) and he admitted that he had forgotten most of the details, could I come out and meet him again to “refresh his memory” and bring more print outs…  I called a few other contractors to start the bidding process with them instead.

In another case, after wasting a month, I started calling a particular ICF distributor every day for a while.  I left 7 messages over two weeks and got no replies.  I realized that I had not got a reply to anything (email or phone) in 2 months.  I did get a reply from him months earlier after meeting him at a trade show, so I know I had the right email and phone number.  I decided to contact the main company and told them I couldn’t get a hold of their exclusive distributor in my region.  They confirmed the contact info was correct and said they would follow up.  Two weeks later, they called to say they tried and tried, but couldn’t get a hold of him either and put me in contact with the next closest distributor.  Actually, this other distributor was much closer to my building site even though I was technically out of their region, and with corporate watching, they got me a good quote in a day or so.

In another case, the office person responsible for quotes kept acting like she was just about to send me a quote.  I kept missing her because she had gone to lunch or was in the shop.  She never called me back.  Eventually she sent me a scan of a hand written quote.  I couldn’t read it (it was too faint to make out her handwriting), but I could see that it was only a few lines long and couldn’t possibly be complete, so I called again and this time I got her.  After 5 weeks, she told me that the drawings in the packet I sent were not sufficient and I would need to get shop drawings made before she could quote accurately.  I thought the drawings were good enough, so I asked her what she would like to see.  We opened the excel doc that I sent here at the same time so were were looking at the same thing.   She started saying how it didn’t give enough info to bid…  I asked her if we could go thru a row together.  We started on the first row, and it was clear that she had not got past the 5th column.  Once she saw that, it started to click for her.  Then I got her to pan over even further to the right where I had inserted the drawings in the sheet (I had also sent them separately as PDFs which she had not noticed).  The lights went on (I heard a little gasp) and she said she would get me a proper quote right away.   That was 10 days ago, I guess I should call her again.

In another case, I had met a contractor who had impressed me by already printing out the drawings I had sent him so I didn’t need to give him my set.  We were going thru the plans and he said that he guessed most contractors would take one look at these plans and decide that it would be easier to bid on a more standard job.  But he thought it was cool and he give me the name of a contractor for another part of the project who he though would also think my project was cool enough to want to be involved…

My main shotcrete contractor has not yet been able to meet with me or talk to me since I started the bidding process.  He is just too busy and I am starting to get concerned.   I will call him again this week and try to set something up.

A number of the contractors I have spoken to have said they would need to bid “time and materials” for such an uncertain job.   For a contractor to make a bid, he is betting that he can get a job done to your satisfaction for less cost than the bid.   He needs to estimate carefully so that he makes his bet correctly.  If he bids too high, you will choose someone else, if he bids too low, he may end up losing money (worse than you choosing someone else).   All the contractors make sure to guess a bit high to protect themselves.  You are paying a bit more than they really think it will cost because you are paying them for the risk of the fixed price bid.   On the other hand, if they can send in a “time and materials” bid, they are passing the risk over to you.  You should expect to pay less if all goes well, but pay more if it doesn’t.  The problem with “time and materials” is a lack of motivation for the contractor to get things done efficiently.  If you want things to go as slowly as possible, pay by the hour.  However, if you trust the contractor to work at a reasonable speed, “time and materials” gives a lot of flexibility.  You can ask them to add something without needing to renegotiate.  It will just add to the time and materials cost.

 

After a number of weeks, one of my steel stud contractors got back to me with a quote that was about 10 times what I was expecting (well over $100k for just the vertical steel stud work).  So that was shocking…  I thought maybe he had mistyped, so I wrote him back and asked him to separate it into Labor and Materials.  I thought he would catch his mistake, but he just confirmed that it was more than $30k for materials and more than $80k for labor, for just the steel studs…  Ouch.

But then I got talking to another steel stud contractor who told me that I would probably need specific drawings of how all the steel studs went together.  He said it would be helpful for his quote, but probably required by the county building inspector.  I asked the inspector about it and he gave some cryptic answer about how I should want the drawings so I would have a better record of what was hidden behind the walls.  I wrote back and asked if he could be more clear about if I need those drawings or not.  My architectural drawings just have one wall detail cross section with a note that says something something basic and generic like “STEEL STUDS, 24″ ON CENTER”.  My steel stud work is very basic, with no load bearing walls or connections with floors or roofing assemblies…  I can always take a photo before the walls are closed if I wanted good records.  I am still waiting to here if I need these, but if I do, it will be more expense.

And on and on it goes.  I should be making a bunch of calls this next week.  But I also need to keep my job ;^).   My plan is to make an hour of calls in the morning and another in the afternoon each day, and then to just extend my work day by a couple hours…  I am very glad that my job is flexible enough to get away with that kind of time management so I can save my vacation days for actual construction.

 

Contractor Pet Peeve…

One of my pet peeves is how secretive the contractors are about where the costs come from.  The GeoThermal guys are the worst because they have big chunky components that should be the easiest to quote.  They want to make it seem like they need to do this big fancy energy audit before they can possibly work on the quote.  But in actual fact, they only have 3 hydronic units (for radiant floor) and I want the small one.  Then they start to say that the load requirements determine the feet of pipe they need to bury, but later admit that hardly changes the price at all so they always put in more than they need…  petpeevespicStill, the price is a mystery.    This is particularly annoying when I am trying to decide if I need an add-on.  For instance, I am not sure I need AC, but wanted to check the cost of adding the air handler.  They only have one model that would be compatible with the rest of the system I need, so I asked for the price…  They gave me a range that was so wide that the high number was double the low number…  As I have said before, I find informational asymmetry frustrating.

 

Permits

I had planned to avoid spending money as long as possible, so I was going to wait on the permits until after I got the bids in.  Also, many of bids I had already received included that they would file for the permits.  This is probably right for some of the permits (well, pluming, electrical, mechanical), but the septic field size needs to be set by the county based on some formula that takes the number of bathrooms and bedrooms into account.  Apparently this size is specified in the permit, which the excavator needs before it can be accurately estimated…  So we need to take care of that sooner rather than later.

Fortunately, my wife has taken over the permit stuff.  She recently spent a couple hours following the daisy chain of permits and printing them out as she goes.  I will let her explain it better in her own post if she ever finds the time, but it doesn’t seem like a nice clear set of paperwork.  Instead, it is more like a branching tree.  Each permit needs several other permits filled out first and she is following it to the bottom.  We joked that our county is very “liberal” which is why there is so many restrictions and complicated paperwork is required to do anything. She has already covered a large desk in forms organized into some sort of hierarchy.  Now to fill them all out. ;^)

 

Eye Candy?

Sorry, none today.  This post is already too long.  But I will come back soon and do a special Eye Candy edition this coming week.

 

Earth Tube Concerns

Posted on August 19, 2012 by

Earth Tube Concerns

A variety of concerns are often stated as reasons why earth tubes should not be used or may even be dangerous.  These range from concerns about cost effectiveness to serious health concerns related to mold or radon.  In general, these concerns are based on anecdotes or experience improperly installed earth tubes.

Earth Tubes and Radon:

One earth sheltered home owner I spoke with told me that after many years of living in his earth sheltered home and loving his earth tubes (his wife told me how much she liked the natural humidity control), an air quality test showed that they were bringing in high levels of radon gas. Radon is an inert “noble gas”, 8 times more dense than air, that also happens to be the radioactive offspring of Uranium decay.   The inspector told them that the level found in their home was the cancer causing equivalent of smoking several packs of cigarettes a day.  They immediately plugged up their earth tubes.  But what had gone wrong?

While the danger of cigarette smoke in now almost universally accepted (well paid tobacco lawyers and tobacco executives excepted), there is actually still some controversy about how dangerous naturally occurring Radon actually is.  Controversy or not, it makes sense to assume that radioactive R86 is probably something you want to avoid if you have a choice.

 

Radon works its way out of the ground thru little gaps in the soil.  This is a natural process that happens all the time, but the radon is usually dissipated quickly.  The problem starts when earth tubes can provide a sort of Radon collection system, a path of least resistance that draws in all the radon from the soil around the home.  Once the radon is channeled inside an airtight home, the heavier-than-air gas can become concentrated.

Many earth tubes are made from flexible drainage pipe with weep holes along every inch of it.  This is great for humidity control as it lets moisture in an out as needed, but it also makes it easy for radon to enter the pipe.  Sloping the tubes toward the home also makes it a bit easier for the 8x-denser-than-air radon (and water) to enter the home.

Using sealed solid wall earth tubes (such as HDPE double wall pipe) and sloping down away from the house to daylight, prevent both of these problems.

Even if radon (which only has a radioactive half life of less than 4 days) does enter the home, it is really only a concern if it is trapped in the home and becomes concentrated.  Actually, this can even happen in “normal” homes with poorly sealed basements and poor ventilation.

Homes that allow for a proper number of air exchanges each day, should not have Radon problems. In fact, a good earth tube system that provides ample air exchanges can actually be the solution to a radon problem.

Earth Tubes and Mold

Every now and then an earth sheltered home or PassivHaus gets diagnosed with “Sick House Syndrome”.  Here is an example,  In this case, the problem was really in the walls, but the earth tubes were not sloped to drain and were actually collecting rain water directly...  Generally, these houses are unhealthy because they literally can’t breathe, and the levels of internal pollutants (chemical and biological) build up (become concentrated) to the point where they irritate the occupants and may even cause serious health problems.  In extreme cases, the home may even be condemned.

A properly designed and installed earth tube system could provide for healthy air exchanges, so it is ironic that the headlines often blame the earth tubes, specifically, mold growing in the earth tubes, for all the problems.

We all know that mold likes to feed on organic material in warm, moist dark places.  No one wants to breathe air that just passed thru a mold filled earth tube.   The idea that earth tubes provide this environment scares many people away from the whole idea…    Properly designed earth tubes should not provide the right environment for mold.  They should be warm and dark, but without the right level of moisture or anything organic to eat.

Keep in mind that even prairie dogs can engineer an earth tube system with enough flow to keep their dry grass bedding from molding.  The keys to a successful earth tube design are slope and airflow.  And choosing a nice smooth inorganic material (like HDPE plastic pipe) helps too.

Water can get into earth tubes by seepage thru joints or holes, but mostly it is by condensation on the inner surface as warm moist summer air flows thru a cool tube.  In some particularly poor designs, rain water can enter directly.  These problems can be avoided with careful design.

Condensation is unavoidable and happens when warm moisture laden air comes into contact with the cool pipe walls.  If this moisture sits there, it could make a suitable environment for mold spores that happen to pass thru.  So don’t let it sit there!

 

A stagnant earth-tube just sits there stewing… but good airflow can either bring in dry air that will absorb the moisture, or it can bring in more humid air that will condense further until the weight of the droplets exceeds the surface tension and friction holding it in place so that it will run down to the lowest point in the pipe…  A proper design anticipates this water and directs it out to daylight or into a drainage pit.

In some cases, builders have used HDPE pipe with an expensive antimicrobial coating on the inner surface.  I suspect the expensive coating is overkill.  However, the smooth walls and seams of HDPE pipe promote greater airflow and allow water to drain away more easily (provided the pipe is sloped), which probably does make a difference.

The real kicker is that scientific studies of microbial and fungal growth in earth tubes actually show a net benefit as these two quotes explain.

“The Earth-Air Tunnel is found not to support the growth of bacteria and fungi; rather it is found to reduce the quantity of bacteria and fungi thus making the air safer for humans to inhale. It is therefore clear that the use of earth-air heat exchangers [earth tubes] not only helps save the energy but also helps reduce the air pollution by reducing bacteria and fungi.”                                           ~~~Rabindra Nath B, Shailendra Kumar M, and Pawan Basnyat; Use of Earth Air Tunnel HVAC system in minimizing indoor air pollution; Air Quality Monitoring and Management, proceedings of Better Air Quality 2004.

“This study [of 12 different EAHX] was performed because of concerns of potential microbial growth in the buried pipes of ‘ground-coupled’ air systems. The results however demonstrate, that no harmful growth occurs and that the airborne concentrations of viable spores and bacteria, with few exceptions, even decreases after passage through the pipe-system”       ~~~Flueckiger B, Monn C; Microbial investigations and allergen measurements in ground-coupled earth-to-air heat exchangers; AIVC 20th Conference and Indoor Air 99, the 8th International Conference on Indoor Air Quality and Climate, UK, Garston, BRE, 1999, proceedings, Edinburgh, Scotland, 8–13 August 1999, Volume 5.

 

Earth Tube System Saturation

Thermal saturation is a very real concern that is often underestimated.  Many books and articles on the subject repeat the false idea that the temperature of the earth at some magical depth (5, 10 or 20 feet depending on the writer) is stable at some fixed temperature all year long.  These articles overly simplify the situation and make the soil around the earth tubes seem like an inexhaustible thermal reservoir.  Of course, the laws of physics, including laws about transfers of energy, still apply 10 ft below the ground.  Please see the results of my own experiment to get an idea of an actual underground temperature profile…

The moment you bury an earth tube in that “stable” environment and start to run air thru it, you start to change the temperature profile of the environment.   The original temperature profile was somewhat stable because it was separated from the air by 10 or 20 ft of compact earth.  If you now bring the air down into the earth for the purpose of exchanging heat with it (Ground – Air heat exchange), you should expect the temperature of the earth to vary according to that heat exchange.   If the soil warms up air in the earth tube on a cold day, that thermal energy must come from somewhere.  Of course it comes from the soil, and in the exchange, the soil temperature will be reduced proportionally to its higher mass and heat capacity.   If the air is cold and is warmed by the earth, the earth will cool down during the exchange.  This is why it is called an “exchange”.  The rate that the soil is warmed or cooled is affected by things like the exchange surface area and conductivity, the volume flow rate of the air, the temperature difference (which drives the conduction and is constantly changing during the day), the mass of the earth in proximity to the tube, how quickly the heat from the surrounding earth is conducted to the earth next to the tube, etc.

Since this is a dynamic conjugate heat transfer problem, it is very difficult to predict the exact behavior.  However, if your tube is too short or your air flow is too high, or your ΔT is too great, you could quickly exhaust the thermal difference between the air and the soil near the tube.  As the temperature difference drops, the heat exchange will slow to the point where the earth tube becomes thermally saturated and ineffective.    In a cooling situation, it is possible that by 10 or 11 in the morning, the warm air could increase the temperature of the soil to above the desired room temperature.  For the rest of the day, hot air flowing thru the pipes would just keep increasing the temperature of the soil around the pipes with the theoretical maximum being the outdoor air temperature.  (I plan to use this to my advantage by solar air heating the soil during the summer, see the section on “by-passive” solar).  

In a truly successful earth tube design, the pipes are long enough and the flow speed is low enough that the exchange between the earth and the air happens at a rate the earth around the tubes can absorb.  Since the external air temperatures fluctuate on a daily cycle, it won’t be a truly stable system, but at least it shouldn’t run out of ΔT.  In an even better design, this air flow can be driven by completely passive processes.

In a closed loop system, air is cycled thru the system over and over again.  You don’t get fresh air, but the ΔT is lower, so the earth air exchange system can handle more airflow.

 

Earth Tube Cost

It is very possible for the install of an earth tube system to cost thousands of dollars.  Many have performed cost benefit analysis and decided against installing them (opting for an air to air heat exchanger instead). I myself have spent many hours agonizing over how to reduce the cost of an earth tube system (while also reducing other risks) in order to make it viable.   Costs can be broken up into 3 main areas; Materials, Installation and Operation/Maintenance.  Of course, the benefits of the system is mostly related to the effectiveness of the system, which is dependent on good design.  Take a look at the Earth Tube Design section of this site.

One way that I planed to reduce the cost of my earth tubes was by reusing the trenches already planned for drainage and sewerage.   Less additional trenching meant less additional cost.  I also needed to compromise on my depth to keep costs down, but I still ended up with depths of up to 15 ft (20′ would be better).

The cost effective depth depends on length of the arm on the excavator, so greater depth may just be a matter hiring an excavator with better equipment.  In my case, the contractor I hired had several large excavators to choose from and came with one that made short work of the trench for the septic line.  It went from the basement of the house (10 ft deep) and cut thru a bit of a hill (up to 15 ft deep) on its way to the septic field nearly 200 ft away (the location at the bottom of the hill was specified by the county health department).  I manually put back a foot or so of earth over the septic lines before placing my double wall earth tubes, that whole manual process took my wife and I most of a Saturday.   When the excavator back filled the hole, he probably took a couple extra hours because he had to be a bit more careful regarding my tubes during the process.

Earth Tubes in hot & humid environments:

If you have 80% humidity at 35°C entering your earth tube, and it cools to 25°C degrees, it will drop a lot of water as condensation on the earth tube walls, but this drop in temperature only increases the level of humidity.  In addition to manageable concerns about where all that condensate goes, the “cooled” air may enter your space at 100% humidity.

This is a real concern and many experts simply recommend against using earth tubes in these environments.

However, I have a two stage arguments for earth tubes in hot and humid environments.

1) The humidity level within the earth tube may increase to 100%, but then it enters the larger habitable space which probably has a higher temperature, so the humidity will automatically drop again. The total moisture in your habitable space will be less than without the earth tubes because some of it was left behind in the tubes.  The cooler your earth/tubes are, relative to your habitable space, the better the natural de-humidification.

2) Assuming the earth is cooler than your habitable space, the earth tubes will remove at least some of the moisture from the air. If you need to remove more with a dehumidification system, you are still better off than without the earth tube. Perhaps the earth tube will enable you to choose a smaller system or use a desiccant wheel or something like that.

After that, it becomes a cost benefit analysis to see if you can put in earth tubes economically enough to make it worth your while.  Often, these hot and humid areas have lower labor rates that make earth tubes more affordable than importing expensive dehumidification equipment.

I am in Michigan, which has cold and relatively dry winters.  However, the summer and fall seasons can be hot and humid.  Hot enough that I also expect my earth tubes to reach 100% humidity and condense out gallons of water per day.  This is why I used smooth wall HDPE earth tubes and sloped them carefully.  It is also why I plan to pass my earth tube air thru an efficient dehumidification system before being distributed thru my home.  My neighbors will simply draw in the hot humid air directly.  The difference will be how much harder their system has to work to dehumidify the air.