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Matt Risinger's Building Science Summer Camp Interviews

 
Table talk at Building Science Summer Camp

August for me is dominated by Building Science Summer Camp. It's a great event with lots of learning, great discussions, and meeting friends, old and new. I'll be writing about Dr. Chris Timusk's presentation on his OSB research later and possibly one or two other topics. Hal Levin spoke most of Tuesday, and, after his rambling, two-hour introduction, his talk on indoor air pollution was full of useful information. Today, though, let me just give you this nice little video that Matt Risinger put together from interviews he did with me, Joe Lstiburek, and Mark Laliberte.

The Pen Test — A Control Layers Tool for Architects and Contractors

 
pen test liquid water control layer epa moisture guide 550

I listened to the IAQ Radio podcast a couple of weeks ago when they interviewed Lew Harriman and Terry Brennan, who were discussing the new moisture control guide published by the EPA last year. Brennan is the lead author of the document, and it's a really great resource full of useful information about indoor air quality, fundamental building science principles, and how to control moisture. If you have anything to do with buildings, you really should download it now and read it.

4 Ventilation Quotes That Will Rock Your IAQ World

 
perforated buckskin underclothing ventilation iaq quotes

I've been writing some articles on ventilation for the Journal of Light Construction lately and have come across some great material. The first quote here makes the point about indoor air quality with a graphic underwear metaphor. It's from an 1893 book whose author was a medical doctor and interested in ventilation to prevent diseases like phthisis (what we now call tuberculosis).

Can You Save Money by Closing HVAC Vents in Unused Rooms?

 
air conditioner heat pump furnace supply vent register

Your air conditioner, heat pump, or furnace probably uses a lot of energy. Heating and cooling makes up about half of the total energy use in a typical house. For air conditioners and heat pumps using electricity generated in fossil-fuel fired power plants, the amount you use at home may be only a third of the total. A question I get asked frequently is whether or not it's OK to close vents in unused rooms to save money. The answer may surprise you.

FBI Investigates R-22 Substitute Air Conditioner Refrigerants

 
R-22 air conditioner refrigerant

And the battle over air conditioner refrigerants continues. The US EPA just issued another warning, "cautioning homeowners, manufacturers of propane-based refrigerants, home improvement contractors and air conditioning technicians of the safety hazards related to the use of propane in existing motor vehicle and home air conditioning systems." Now the FBI has entered the battle, too.

A Line in the Sand — The Dew Point Duct Duel

 
crawl space vented duct condensation drop

A line in the sand has some significance for Texas, the state where I was born. Colonel William Travis used his sword to draw such a line in the waning days of the Battle of the Alamo. As General Santa Anna had the Texans completely surrounded and asked for their surrender, Colonel Travis asked for all those who would join him in fighting to the death to cross the line and stand with him. As you can see below, homes in hot, humid climates sometimes draw a line in the sand, too.

The Sucking and the Blowing — A Lesson in Duct Leakage

 
disconnected duct unbalanced supply leakage

Duct leakage is a big deal. It's one of the top three energy wasters in most homes (air leakage and cable TV set-top boxes being the other two). Researchers at Lawrence Berkeley National Lab found that duct systems leak on average about 10% of the supply air they move and 12% of the return air (download pdf). In far more homes than you might suspect, the main culprit is a disconnected duct, as shown below, but a typical duct system has a lot of other leaks, too. But another problem occurs with the duct leakage to cause even more wasted energy.

Is the Aros Smart Window Air Conditioner Worth the Hype?

 
window air conditioner

When it comes to air conditioning, there are a lot of bad products and bad ideas out there. Here are a few: You can buy a cover for your condenser that could kill your compressor. Some people don't think the outdoor unit really needs to go outdoors. (They're wrong!) And then there's the strange notion that attaching a kraken to your air conditioner is a good way to distribute the air. Today, though, I'm going to look at a product that's not terrible.

Fermi Problems, Blower Doors, and the Compressibility of Air

 
Enrico Fermi estimate question problem

Enrico Fermi was famous for many things, as you might expect of one of the smartest physicists of the 20th century. Quantum theory,  statistical mechanics, and nuclear physics were his primary subjects, but what I appreciate most about him was what are called Fermi Problems. He had an amazing ability to come up with estimates for questions for which he had little or no real data.

How Is a Blower Door Like a Hydraulic Jack? Pascal Knows!

 
Blaise Pascal

Remember the first time you ran a blower door? OK, maybe that's not the best way to get where I'm going because most first-timers turn the pressure up like they're practicing tai chi on Jupiter. After you've done a few tests, though, you learn to crank it up to 50 Pascals of pressure difference in just a few seconds. And that's where you may have discovered the mystery that Blaise Pascal solved nearly 4 centuries ago when he invented the hydraulic press.

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