The Art of Building Science – Soup to Nuts Webinar Series

We are trying something new that we hope is helpful for those of you who would like to take a deeper dive into Building Science but can’t take time out of a nutty work day to do so.

Because I live Building Science every day, I occasionally lose sight of the fact that not everyone sees how all of this information works and fits together.  Sadly we live in a bullet point world so let’s give the big picture the opportunity to talk. Let’s give the silent masses the opportunity to ask questions and engage with folks who work with this knowledge on a daily basis in real world scenarios.

The early evening timeframe for this series may have particular value for younger architects and building professionals who do not get to take time out of billable hours but could jump online at the end of the day.

We are offering the opportunity to see the Big Picture of Building Science through a series of three webinars starting at 5:30 pm EST over the next three months that will take you through topics such as Heat Flow, Moisture Flow, Air Flow, Indoor Air Quality, Evaluating HVAC or Mechanical Systems in the Building Envelop and Sound Control Problems.

Be forewarned, each webinar is a half hour longer than the last.  It is like a three course meal that will leave you both full and wanting more.

The first session will be held on Wednesday, March 12 from 5:30 – 6:30 pm EST.  If you are looking to expand your knowledge of Building Science, this accredited course is for you!

Register and join me for The Art of Building Science Part I.

The Greening of the 2012 Building Codes: Air-tightness Testing – A Must Have for Consumers

 

Blower Door Testing

Blower Door Testing

The 2012 energy code, which we are very excited about because it is very advanced compared to the 2009, requires two things which have never been required by aU.S. code before.  These are:

  • Blower door testing of houses
  • Duct pressure testing for leakage

These two things are extremely influential on energy efficiency and have always been assumed were part of best practices. We have seen changes in the codes saying “install air barriers or tighten up your duct work” but they never required that these tests be conducted to ensure that the house is airtight.

These are two physical tests that need to be conducted on every new home if the 2012 building codes have been adopted by a state. While this is one of the best ways to ensure efficient thermal comfort for home owners, the potential impact on the builder must be understood. If you are building a house in say 120 days scheduling someone to come out to conduct this testing could severely impact the building schedule: these tests need to be conducted before installing the drywall. No drywall until you have passed the inspection- imagine it.

But who conducts this testing?  Code officials are not typically trained or funded to execute this type of testing.  This testing has been done in the past for NAHB, Energy Star and other programs by internally or externally certified raters. Home Energy Rating System (HERS) raters are a great example of one group that is trained to do this testing.

However, there is no organized resource, clearinghouse or national database for building professionals to find all of the various local professionals who can conduct these tests. To ensure that these tests are conducted and that states do not “opt out” of this requirement, a national database needs be developed so that third-party testers can be easily found and scheduled.

This is an important part of the 2012 code that qualifies for the consumer that the home is energy efficient and that some of the most critical passive elements of that efficiency were done right.  It’s not what you spec; it’s what you inspect.

 

Can We Design Buildings for Heat and Cooling that Mimic the Human Body

Lucas Hamilton

Lucas Hamilton is Manager, Building Science Applications for CertainTeed Corporation

I spend lots of time thinking about buildings. Sad; I know. Lately I have been wondering how we wound up in such a confusing state. It’s like looking under your car hood. Have you looked under your hood lately? It looks like a building design. Who in their right mind would have started out to design such a complicated mess? No wonder we need so many building scientists and we pay a hundred bucks an hour to get our cars fixed. Can we step back for a minute?

Thermal comfort in the built environment needn’t be so complicated. If we could start from scratch and try to make buildings comfortable based upon our own organic experience, what would we do? I live in Philadelphia.  If I go outside in the winter and try to passively stay comfortable – passively meaning to not use any outside energy sources – I would use lots of layers of clothing, would zip up tight and cover my skin.

Coincidentally that is what we require in our cold climate building codes.  Lots of layers of clothing means R-value. When you wear lots of layers of clothing you are trapping gas inside layers.  The gas is the insulation – gas gives you resistance to conductive energy heat flow – that’s R-value.  So when you are wearing lots of layers you are wearing R-value. When we say zip up – that’s getting air tight. We finally woke up and added that one to the cold and mixed climate codes as well.

The problem comes in the summertime. To stay cool, you would take off those layers, wear light colors and try to get air flow around you.  You would wear airy fabrics to release as much heat from your body as possible and light colors which don’t get hot in the sun. If you were stuck wearing lots of layers and were zipped up tight, you would have to blow cold fresh air into that outfit to stay comfortable. Our goal should be not to do that. Remember, passive technologies rule and active technologies cost $$$.

We need to find ways to help a building be warm in the winter and stay cool to begin with in the summer. I am looking for changes to our practices that will enable us to do to buildings what we do to ourselves. How would you build your building differently?

If you can’t strip off all the layers of clothing the very least you will do is unzip so can we figure out a way to unzip our buildings? I know we want to be air tight in the winter but can we figure out a way to use air to remove surface heat in the summer? I think ventilated claddings may be one answer.

Can you think of some others? To go back to the car analogy, let’s stop bolting more stuff onto the internal combustion engine to make it more efficient and drop in an electric motor. It needn’t be so complicated.

Simple Changes Could Help Consumers Save on HVAC

Lucas Hamilton

Lucas Hamilton is Manager, Building Science Applications for CertainTeed Corporation

California has again pushed their energy bar higher.  One of the things that I love about California’s energy program is that they are now requiring an independent evaluation and commissioning beyond the air conditioning contractor of the sizing and installation of air conditioning systems. 

Recently, I participated in a workshop with a Philadelphia-based builder. He is a very professional, conscientious builder who stays in touch with building science and education. He brought his mechanical contractor to the workshop and we had a chance to talk about the way homes are built and particularly the mechanical systems. 

Here is the situation:

  • There are still ‘rules of thumb’ being applied to the sizing of mechanical systems in our homes. 
  • Manufacturers make changes to equipment to help those ‘rules of thumb’ meet the requirements, especially regarding motors and equipment that can tune itself to the needs of the house. 

What we really need are systems that are designed and installed to the actual house. 

We can’t expect equipment to be continuously updated or modified to make up for our lack of willingness to do a simple calculation as to what the house really needs. It’s not just about the tonnage of air conditioning and the size of the heating units.  It is mostly about the delivery – the physics of the delivery – of that comfort.

When someone tells me something regarding heating or cooling that just isn’t sitting well and I need a gut check, my gut actually lives out in Missouri and his name is Eric Kjelshus. He is a Missouri Mechanical Contractor with his own company, Eric Kjelshus Energy. He is a smart, thorough, well studied mechanical contractor who cares about this stuff far beyond anyone else I have come across.

It seems like many of the builders I have spoken with have been spending a lot of effort (effort = $$) after the sale trying to make the homes they have constructed meet the comfort expectations of the owners. This leads me to wonder if there are things we consistently get wrong with regard to how we deliver comfort. Time for another gut check!

Here is what Eric taught me:

We under return air in our homes.  Very few people consistently measure static pressures in the HVAC system to find out if it is balanced. If they did they would see that the system is not returning the same volume of air it is supplying. When we under return, we force the system to pull make-up air from outside the home.  Air conditioning is more efficient when the air is dry. For most of us residing east of the Rocky Mountains, the return air in our homes is both cooler and dryer than the air outside during our cooling periods. Pulling unconditioned and uncontrolled air from outside the home into the system is a big efficiency penalty and it’s one we pay for over and over again. Why not simply return the correct volume of conditioned air back to the unit? Not only is this an elegant, passive solution to the problem –  it comes with a much lower up front cost than high tech solutions.

So hats off to California for requiring that trained professionals check these systems to ensure they are properly sized and installed. We as consumers can get much better value out of systems that are less sophisticated but are sized and built right.

Rules Matter When it Comes to R-Value

Ken Forsythe

We all know there are ‘rules’ that everyone might not follow to the letter: “Speed Limit 55”…”Do Not Remove Mattress Tag Under Penalty of Law”…”Lather, rinse, repeat.”  When it comes to heating and air conditioning ductwork, there’s another rule many insulation contractors rarely follow:  “When installing bubble wrap insulation on ductwork, secure spacers every 24” to 36” around duct before applying wrap.”

While there’s no harm if you skip the “repeat” step when washing your hair, there can be serious utility bill consequences if installers leave out the placement of spacers between a duct and bubble wrap insulation. Bubble wrap insulation needs the thermal break provided by the air space that is created by spacers to achieve advertised R-values.  The actual R-value of improperly wrapped (i.e. no air space) duct with bubble wrap can be as low as R-0.90 to R-1.1.  Building Inspectors and owners need to be aware of what to look for to insure that the product performs properly.

In checking with HVAC insulation distributors to determine if insulation contractors routinely purchase air spacers with their bubble wrap, the answer is often “We’re still on our first shipment of spacers” or an outright, “We never sell any of those.”

Often bubble wrap insulation manufacturers do include spacer instructions with options for installers to create their own spacers by cutting and placing 2” wide strips of bubble wrap around the duct in intervals before applying the wrap around the duct or applying corner spacers specifically made for the purpose at each corner of rectangular duct.  But with so much pressure on insulation contractors to keep labor to a minimum, it’s hard to imagine that the vast majority are taking the time to create or use spacers on every project. Let’s face it: installers care about installing as quickly as possible for the lowest cost.

It’s true that quality bubble duct wrap may have good reflectivity and provides some protection against conductive heat gain or loss – as does fiber glass duct wrap with FSK (Foil-Scrim-Kraft) facing – however, the bubble wrap industry needs to do a better job educating installers and/or HVAC contractors. Educating the industry about the science behind adding air spacers and their integral role in delivering promised R-value is an important first step and is in everyone’s best interests.

 Ken Forsythe is a Senior Product Manager for CertainTeed Mechanical/Industrial Insulation