Posts Tagged ‘technology’

NEBSI & System Dynamics

October 26, 2017

We like to say that, “A house is a system”.  If you change one thing in a system, something else is likely to change.  It’s not always something that you are expecting to change.  The spotlight over the sink in the kitchen may generate enough heat on the surface of the roof above to melt the snow. The water runs down the roof and freezes, creating an ice dam.  The water backs up under the shingles and runs down inside the wall cavity and shows up in the basement.

Consider the house as a thermal system.  When it’s colder outside than it is inside, the house loses heat and cools.  It will continue to cool until the inside temperature reaches the outside temperature.  The regulator is the ability of the structure to resist the flow of heat.  A heating sVensim House Temp1ource in the house moderates the flow. The loops in the system can be modelled mathematically; each loop impacts the others in a model that can be increasingly complex as details are added.

Consider the occupants in a house.  If you consider their health as similar to the temperature, if there is carbon monoxide in the house, the more CO the more dangerous the environment.  The system loop is simple to predict – the more CO the more impact.  The cause of the CO is the driver of the loop.  Determining the cause of the CO requires knowledge of what creates CO.  The analyst who determines the cause needs to be trained.  The more knowledgeable the analyst the more the correct cause will be determined.

The loops continue to flow out, driving just this one aspect of the health in a house.  The occupants need to understand that they should not take the batteries out of the CO detector.  The code officials need to know that CO can be caused in a house and enact legislation that CO detectors are required.  Code officials have to confirm that the regulations have been complied with.  Insurance companies need to know that the occupants of the house won’t be at risk.

All of these complex loops can be modelled so that the system can be made understandable, any missing elements determined, and the most important points highlighted.  Where would more training make the most impact?  The more participants who understand the systems, the greater the impact on making homes safer, more comfortable, more affordable, more desirable, healthier, and more energy efficient.

The NorthEast Building Science Institute (NEBSI) is based on developing such understanding and making the connections and improving the system.

NorthEast Building Science Institute (NEBSI)

Systems Dynamics Society


Remembering Common Sense

March 23, 2015

A house is meant to be a shelter from the weather, a small, controlled subsection of the planet earth where a family can live safely and comfortably. Caves worked but they were hard to keep warm. But they mostly kept the rain off and blocked some of the wind. House design has advanced over the years becoming safer and more protective. Most of the time. There have been problems with chimneys, for example. A hole in the roof works to let some of the smoke out, but it was an improvement to enclose more of the smoke and guide more of it out. But there was a problem with wooden chimneys. Common sense dictated that chimneys be built of fireproof materials. In fact, many of the improvements in building science were dictated by common sense, wisdom, and skill. The problem came into it when unskilled builders decided that it couldn’t be all that hard and there was money to be made by ignoring some of the details. So rules and codes and standards were created.

Now there isn’t anything inherently wrong with having rules and codes and standards. The problem is that the focus tends to drift from why the rule or code or standard was created in the first place to developing rules and codes and standards just to regulate the rules and codes and standards. Let’s face it: we’re not perfect. And our rules and codes and standards won’t ever be universally perfect either no matter how hard we tweak and tinker and debate. Some people like a airconditioned thatchlittle more salt on their meat and some a little less. And some don’t like meat at all. One rule that covers all the ways to eat a steak simply wouldn’t work. We could have committees and conferences and technical papers ad nauseam but we would still never come up with the perfect rule. When a committee or a society or a club self-perpetuates by simply constantly making changes to a set of rules, the original point is lost. No doubt we are learning more and things change, but we’ve lost the link to common sense. There is no room in our rules or codes or standards for the application of common sense! And we need to just stop and try to remember why the rule or code or standard was written in the first place!

What is the fundamental, bottom line point for the existence of the ASHRAE 62 Standard, for example? (Having been on that committee for over ten years now, I feel that I have a right to use it as an example.) The Standard says, “This standard defines the roles and minimum requirements for mechanical and natural ventilation systems and the building envelope intended to provide acceptable indoor air quality (IAQ) in low-rise residential buildings.” That sounds pretty reasonable. The basics of the standard are great – segmented and detailed to define important stuff. Why can’t we just finish it? Maybe tweak it a little once in a while as we learn more and technology improves. But a huge amount of brain power and hours of discussion and tons of paper go into the constant adjustment of the standard.

When a 747 is landing, it is important for the pilot to line the plane up with the runway accurately so that that little or no adjustment is need to keep the plane rolling straight when it touches the ground. At those speeds, any moderately radical change of direction would be disastrous. A consensus standard is the result of general agreement about diverse views. Can you imagine what would happen if a 747 was landed by a committee? A compendium of diverse views doesn’t always allow room for common sense.

If you are planning to challenge the BPI Quality Control Inspector’s certification, you might find the Quality Control Inspector’s Residential Handbook helpful. Publishing date is June 1, 2015.  Add your name to stay in touch.  Thanks.

QCI Handbook Cover copy

Innovations Under the Sun

August 13, 2013

I am really, truly glad that there are new minds getting into the solar and energy efficiency world.  When I got into this Colorado-Mesa-Verde-National-Park-cliff-dwellingbusiness back in 1977, everything was new . . . to me at least.  There were numerous luminaries out there who became my heroes.  The fundamentals of the second law of thermodynamics were true then and are true now, but technology has changed rapidly since I used the heat from the transmitters in a local radio station to heat the basement offices or when I glazed the cinder block south wall of a newspaper to act as a massive, passive solar collector.  When the oil embargo hit the country and we waited in line to buy gasoline, the fear was that we were going to be cut off from fuel for heating our homes and a massive amount of innovation took place.  We called the homes Passive Solar Homes, but the adjective, solar, was dropped when the house as a system concept took hold.  The thing is that there was a vast amount of innovation being done, and that technology is out there and available and we shouldn’t go about reinventing the wheel unless you want to make the same mistakes again.

There is a fantastic book on “The practice of the Art of Ventilating Buildings” written in 1891 that you can read on-line: Since this was written prior to the use of electricity in homes, William Buchan’s solutions are all passive.

More recently is the work of Bill Shurcliff.  Dr. Shurcliff was born in 1909 and worked on the atomic bomb.  He died in 2006 with 19 patents to his name.  In the later part of his life he turned his attention to solar energy and energy efficiency and would attend monthly luncheons at MIT.  As a prolific writer, he produced a number of amazing books on the subject many of which are available on Amazon:

Solar Heated Buildings of North America – 120 Outstanding Examples, 1978

New Inventions in Low-Cost Solar Heating – 100 Daring Schemes Tried and Untried, 1979

Air to Air Heat Exchangers for Houses, (personally published in 1981)

Thermal Shutters and Shades, 1981

Super Insulated Houses and Double Envelope Houses, 1981

Ned Nisson also wrote a book on super insulated houses: The Super Insulated Home Book.  Ned was the editor of Energy Design Update.  There are a bunch of other books on super insulated houses that should be reviewed.  Certainly insulation technology has changed since 1985.  We thought that urea-formaldehyde was the greatest thing going.

The Solar Home Book by Bruce Anderson the editor at Solar Age magazine was my Bible.  My copy is barely holding together, and I still use it.  The Passive Solar Energy Book by Ed Mazria (who was rumored to have played for the Knicks) concentrates on the solar aspects of the design of homes.  Check out Ed’s 2030 Challenge:

And there is an amazing book called The Solar Energy Handbook written by Henry Clyde Landa, Mariann Cox Landa, Juliet Marie Landa, and Douglas Cox Landa.  I have a hand typed copy of this that has information in it that I can’t find anywhere else.



Steve Baer of Zomeworks invented some amazing things.  His Beadwall product used polystyrene beads to fill up the cavity between two panes of glass in evening, and a vacuum extracted them in the morning.  (I still have a Beadwall tank in my garage that I never had the courage to install.)

There were Waterwalls and Earth Tubes and inflating window shades and Thermol 81 and Ecosea houses and Amory Lovins’ solar briefcase.  Some of these technologies did not survive because they were not good, but many good technologies were lost because the companies were under-funded or run by enthusiasts and not business people.  It would be great if we could develop a building science resource library so that the technologies could be tapped into and the many mistakes that were made would not be repeated.  There has always been a struggle between the passion for improving the environment and developing, producing, and selling products.  Passivhaus seems to have been able to transcend the struggle.


Please visit our website for some innovative products:

Test As We Work

August 1, 2013

Ad-SocratesWhen Socrates sat around with his students discussing the issues of the world, they didn’t have laptops or cell phones, piles of books or even papers.  If they did have tablets, they certainly didn’t look like they do today! The students really needed to pay attention and remember what was talked about.  Even later, stories and histories were passed on from person to person.  Carpenters, stone masons, cobblers passed along their skills by demonstrating their techniques.

Now students sit at desks or tables in classrooms and watch Power Point pictures, often covered with words.  They have to be able to read and understand sentence structure.  And then there is the testing.  I just finished teaching a class on heating and distribution systems.  One of the questions on one of the daily tests was:

Steady State Efficiency is measured with a digital gas analyzer in undiluted flue gases.  True or False. 

What is important here?  The students need to know what “Steady State Efficiency” is.  Steady State Efficiency is a measurement of the efficiency of the appliance when it has reached steady state combustion after about five minutes of operation.  It is a combination of the temperature of the flue gases relative to the temperature in the combustion appliance zone (CAZ) and the Oxygen in the flue gases.  That’s an important part of the process.  And they need to know how to measure it.  They also need to know where to measure it.  Do they measure it in “undiluted flue gases”?  That would mean that the flue gases were not diluted with extra oxygen.  So it would seem that the answer to the question should be “True”.

But whoever wrote the question snuck the word “gas” in there in front of analyzer.  There are a lot of tools that we use in the field – manometers, thermometers, anemometers, gas leak detectors, and combustion analyzers.  We call them different things – sniffers, Balometers, pressure gauges, and maybe gas analyzers.  If you know what tool to use, how critically important is it to have a precise lexicon of names?  Do we need another Standard to define names?  How critically important is it to use the same color hoses on your manometer for each test?  Would it be wrong to say: “The red hose should be connected to the Reference Tap on Channel A of the manometer in order to reference the outside.”?  Certainly not if you’re using a Retrotec manometer.  And in fact if you search for “gas” analyzer on Google, it will reference all sorts of combustion analyzers.

And that’s what this question essentially gets down to.  What the writer was looking for was an answer of “False” because it is not a gas analyzer it is a combustion analyzer.  I was so perplexed by this question that I sent it out to several people who teach and write this stuff every day and they both answered “True”.  So are we testing people on language or on the ability to get the job done?  Are these multiple choice exams really a good test of someone who spends the day crawling under the bellies of mobile homes or in the hot, dark recesses of attics to seal duct work?  Over and over again in these classes I hear the comment, “This class could be improved with more hands-on time.”  We really need to develop a better way to test and train and mentor, with a more comprehensive apprenticeship program.  It would be preferable for a proctor or mentor spend an extended time with a candidate and finally say, “Yes.  This person knows what they are doing.  I would let them test the systems in my house.  My wife and children would be safe living there when he or she had completed testing.”

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Playing a Manometer like a Stradivarius

May 12, 2013

StradivariusA Stradivarius violin is only a beautiful wooden box with strings on it until it rests in the hands of an accomplished musician who can make it sing.  But even in the hands of an accomplished musician, a violin can sound horrible if it isn’t tuned.  Building test equipment is capable of exceptional diagnostics, but only if the user knows how to use them and if the tool is calibrated.

There is so much information being transferred in a building science training class, that there really isn’t time to get beyond the basic functions of most test equipment.  And even in the ensuing years, how often does a technician take time to “play” with a digital manometer, learning the difference between stepping on the hose and having it pinched in a window frame.  What happens when the hose is attached to the Input instead of Reference tap on the manometer?  It won’t explode.  Give it a try.  What about reading the manual?

In any trade or craft, learning the basic tools is just a place to start.  Learning the shape of a letter so you can write it or learning how much paint to put on a brush before you put it on the paper or canvas won’t tell you how to write The Tale of Two Cities or paint the Mona Lisa.  Life moves so fast these days that we don’t seem to have time to linger to gain the wisdom required to use these new diagnostic tools well.  The fear is that once we’ve learned one, the manufacturer will change it so we’ll have to learn all over again.

And how do we know if the device isn’t “tuned” or calibrated?  You can hear it when a violin is out of tune.  When a digital device puts out a digital result on the screen, the inclination is to believe it.  How can it be wrong?  Maybe, with experience, we would know if it’s really wrong with an out-of-the-ballpark reading.  But what about the subtle differences if it’s only slightly out of calibration?  Does it make a difference?  The calibration schedules for most equipment are an approximation of the time the device will stay in reasonable calibration.  The fact is that it is only for sure in calibration at the moment it leaves the calibration bench, but that doesn’t mean that we should ignore the manufacturer’s advice for maintenance.

We have to be careful not to treat buildings like spacecraft.  They aren’t an exact science and never will be.  Mechanical equipment is different, however.  Our heating and cooling equipment has gotten so sophisticated that we will get less than optimum performance if they are not carefully adjusted and maintained and tuned.  And with new quality control requirements, test equipment needs to be calibrated and the calibration records maintained.

At the very least, take some time to learn your tools and read the manuals.  Like a Stradivarius, they’re not cheap.

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Homeowner’s Energy Workbook Part 4

December 9, 2012

Heat conducting through the cup

We have to talk the same language.  Like any other field of endeavor, building science has its own terms, and if we’re going to be working together, we have to speak the same language.  The “potato/potahto” thing is a matter of pronunciation.  But what if I started talking about the lower chord in the attic and you thought I was talking about music, and I thought I was talking about a roof truss?

Before we start down this path, I have to make it very clear that a house is a system.  The parts of the system work together, sometimes in mysterious ways.  But just know that if you change one part of the system, you are going to change something else even if you don’t know it, even if you never see that change.

Conduction, Convection and Radiation:  So let’s start with the three forms of heat movement: conduction, convection, and radiation.  When we talk about conduction we are talking about the way heat moves through a material, molecule by molecule.  As you know, heat moves to cold.  So something that’s hotter will conduct its heat into something that’s colder if the two of them are touching.  Some materials are better at conducting heat than others.  The iron handle of an iron skillet will get hotter more quickly than a skillet with a wooden handle.  When they put those little paper collars on paper coffee cups, they aren’t very thick, but they are thick enough to keep your hand from touching the hot coffee cup which is touching the hot coffee.  The heat migrates through the wall of the cup, but it has a hard time leaping across the air barrier or thermal break to your hand.

When we refer to conduction, we are referring to materials that are touching.  For insulation to do a good job insulating, it has to be touching the surface that it is insulating.  Lying in bed on a cold winter night, the pile of blankets touch each other.  The thermal path from the body in the bed to the cold bedroom air is through all of those layers of materials.

Where this gets difficult is that the insulation in the ceiling has to be touching the topside of the ceiling surface.  Where it’s not touching, there is an air pocket.  And if there is an air pocket, air can move.  And if air is moving its moving heat like blowing on a spoonful of hot soup to cool it down.


Warm air rising off the coffee

Oh, and moving air is called convection.  It’s the next form of heat movement.  Sometimes we want convection, but if we’re trying to stop heat movement, we want the air to be still.  In fact, it is the still air pockets in the insulation that cause it to insulate!  Glass fibers are not good insulators at all.  Glass is a pretty good conductor of heat.  But all those little air pockets in the layers of fiberglass act like that sleeve around the coffee cup.  Heat has a hard time moving through the material because the material to material surface contact is very limited.

Moving air, on the other hand, carries the heat with it, cooling the surface.  Fans moving air around a room make it feel cooler.  Fans running in a computer carry the heat away from the electronics to prevent them from melting down.  As the electronic components heat the air around themselves, the fan carries the heat away, replacing it with cooler, ambient air.

The big fan in the air handler that heats and cools the house does the same thing.  The heat exchanger component in the system gets hot.  The fan blows the heat into the ducting, pushing it out to the rooms in the house.  The heat exchanger cools down with the airflow and then is reheated.

That fan is a big airflow.  The airflows in insulation are very small airflows, but very small airflows will reduce the effectiveness of the insulation.  Air blowing through leaks and cracks in the house, cooling the house are convective losses.  Cold, unconditioned air is drawn in from outside while warm conditioned air leaves.  You’ve paid to condition the air that’s leaving.  You have to pay again to condition the air that’s coming in.  The same thing is true for air that has been cooled when it is hot and humid outside.  Air leaks are a huge percentage of the heat loss in a house.  We’ll find out what percent for your house, but it can easily be 30% or more.

Homeowner’s Energy Workbook Part 3

December 4, 2012

P1000610But let’s go back to your house.  One of the most fundamental questions is where is it?  It’s pretty obvious is that a house in Alaska is going to perform differently than a house in Florida.  It’s probably going to be built differently.  It’s probably going to be conditioned differently.  It’s probably going to be lived in differently.  There has to be some metric that will help to define the environment surrounding the house.  We can’t just say a house in Alaska is subjected to “colder” weather than a house in Florida.  How much colder?  Ooh, a lot colder.  What does that mean?  Well we do have weather bureaus that track all sorts of weather conditions, and certainly temperature is one of them.  We could say that we want to keep our house at at least 65 degrees Fahrenheit so we keep track of how far and how often it falls below that.  In Hawaii, it doesn’t often fall below that, even in winter.  In Alaska it falls a lot below that and quite often!

Wait a second.  We know that high temperature goes to low temperature.  We know that if we take our hot supper outside when it’s 20 degrees out there, our supper is going to get really cold really fast!  So if the temperature in the house is 65 degrees and the temperature outside is 65 degrees, there’s not going to be any temperature change so we’re not going to need to add any heat to keep it warm.  As the temperature outside drops, the difference between the inside and the outside of the house gets larger and larger, the house loses more and more heat and needs more and more heat to keep it comfortable.

The weather bureau keeps track of the average temperature for each day and we can compare that to 65 degrees.  We can add up those differences and come up with what is called Heating Degree Days.  The more annual heating degree days, the colder the environment that our homes are subjected to.  In 2011 Anchorage, Alaska had 8432 degree days.  Key West, Florida had 6!  So obviously, a house in Alaska is going to require more from a heating system than a house in Florida.  We can do something similar for cooling.

Take a minute a go to the Weather Data Depot and plug in your zip code and find out the heating and cooling degree days. I would suggest that you set your balance point to 65 degrees.  A few degrees of heat are added by waste heat from appliances like your refrigerator and light bulbs, as well as the heat from people and pets.  65 is a good base point for the heating system to turn on.  (There are other degree day resources like that will also supply similar information.)

The numbers that you find in books are generally 30 year averages.  Those numbers are great for determining long term heating and cooling conditions.  The web site can give you recent heating and cooling degree days that you can compare to your own heating and electric bills to see how accurate your calculations are.

Just sign here! Trust me!

August 10, 2012
Lawyer on the phone

“Just sign it!”

I know this is not about ventilation or even building science, but I want to say a few words about contracts.  I want to urge people to read before signing.  A contract is an agreement between parties to do something for something.  “If you do this, I’ll do that.”  Pretty simple.  “If you paint the fence, I’ll give you a chicken.”  Could be done in a conversation and with a handshake.  Of course the parties would have to trust each other.  Custom written contracts can be pretty clear and simple too.  They are written specifically to suit a specific situation.  The parties write them, read them, talk about them, and agree to them.  If something goes wrong – “You painted my fence blue when you knew I wanted it white!” – if what would happen was put on paper beforehand  – “If  I don’t like the color of the fence, I’ll give you a scrawny chicken” – then you get a scrawny chicken.

The trouble is that people don’t write specific contracts anymore.  They use something they have used before which often consists of a whole lot of boiler plate legalize that probably doesn’t apply and may even confuse the issue if anyone bothers to read the contract.  And that is where the real problem lies.  Wait!  Here!  Read this Contract if you want this software!  Who reads those things?  The contract could say, “If you use this software, we’ll own your house,”  but no one reads those things.  Of course, the lawyers will tell you that would never hold up in court, but where’s the line?  If you sign a contract that says you will paint my fence and I throw in a clause that says that’s the only fence you can paint for the next three years, would that hold up in court?  Just sign it.  It takes too long to read it.  It’s just boiler plate stuff.  Legalize.  Everybody signs these things.

What happened to trust?  What happened to giving my word?  If we don’t read the contracts we sign, then we are encouraging lawyers to write contracts that may or may not actually apply to the project at hand.  It’s a lawyer’s job to try to construct contracts that are as broad reaching as they possibly can to protect their clients in any contingency.

  1. We need to read the contracts we sign no matter how long or how boring they may be.
  2. Both parties need to agree on the contents of the contract.  To accomplish that they need to be able to talk about the contents.
  3. These points are especially important if the contract is a generic, off-the-internet set of words.

I increasingly run into contracts that say things that I can’t agree to.  Maybe it’s because as I get older, I get pickier about what I agree to.  People might say I am becoming a curmudgeon.  But I am shocked by how many people don’t read the contracts they sign at all.  They really want that job so they’ll sign anything.  There are no negative consequences with contracts until someone screws up.  What happens then if it is a bad contract?  Maybe nothing.  Maybe a lot.  But if I agree to something in a contract, I’m going to abide by it.  I’m giving my word.  If I haven’t read it, what’s my word worth?