Building Science

A lot of home builders and homeowners are getting certified home energy ratings to find out how efficient their homes are. There's also a lot of buzz about HERS ratings, with builders looking at them as a tool for marketing their homes.

Smart people in the home-building industry have a saying about codes: A code-built house is the worst house allowed by law. The implication behind that statement is that if all you're doing is meeting the code, you're probably short-changing the people who will live in the house. The folks at the International Code Council (ICC) are doing their best to make sure that that barely-legal house is worth living in.

We're making progress! With the all the emphasis on energy codes and energy efficiency programs like Energy StarLabeling system sponsored by the Environmental Protection Agency and the US Department of Energy for labeling the most energy-efficient products on the market; applies to a wide range of products, from computers and office equipment to refrigerators and air conditioners. New Homes, more homes are getting Manual J heating and cooling load calculations these days. The intent is for the heating and cooling systems to be sized properly because oversized systems have problems (poor dehumidification, short cycling...).

I grew up with really bad asthma. Not being able to get enough air into your lungs, in case you haven't experienced it, is pretty scary. I remember lying in bed during one asthma attack, gasping for air, wheezing loudly, and feeling like I was going to die. A trip to the hospital for a shot opened up my lungs again that night, but I continued to suffer asthma attacks even into my mid-twenties.

Let's get back to the Pretty Good House concept now. Last month I wrote part 1, called Is the Pretty Good House the Next Big Thing?

Whether you want to build a new home or fix an old one, the way to ensure that you get the best performance is to do the building envelopeExterior components of a house that provide protection from colder (and warmer) outdoor temperatures and precipitation; includes the house foundation, framed exterior walls, roof or ceiling, and insulation, and air sealing materials. right. That means installing the right amount of insulation and installing it well, and it means having an air barrierBuilding assembly components that work as a system to restrict air flow through the building envelope. Air barriers may or may not act as a vapor barrier. The air barrier can be on the exterior, the interior of the assembly, or both. with minimal leakage. But how do you know when you've done enough air sealing? How tight is tight enough?

On my thousand-mile quality assurance road trip last week, I visited a house that was designed to produce more energy than it uses, making it a net zeroProducing as much energy on an annual basis as one consumes on site, usually with renewable energy sources such as photovoltaics or small-scale wind turbines. Calculating net-zero energy can be difficult, particularly in grid-tied renewable energy systems, because of transmission losses in power lines and other considerations. energy home. You can take any house all the way to net zero just by giving it enough on-site power production (photovoltaics, wind, hydropower...), but that's not the most effective way to achieve the goal of net zero energy use. First, you want to make the house really efficient, and that's what these folks did.

I love the Pretty Good House concept! The folks up in Maine who've been developing this idea in their monthly green building discussion group (Steve's Garage) have struck a chord with a lot of us who design, build, or verify green homes. The growing complexity and expense of green building and energy programs has ledLight-emitting diode. Illumination technology that produces light by running electrical current through a semiconductor diode. LED lamps are much longer lasting and much more energy efficient than incandescent lamps; unlike fluorescent lamps, LED lamps do not contain mercury and can be readily dimmed. to growing frustration.

Recently, I wrote a little article about the stack effect to explain that the flow of air and heat is upward in winter but downward in summer. Turns out, the stack effect is a hot topic. That article has gotten 25 comments so far. When I posted it to the RESNET BPI group on LinkedIn, it got another 22 comments.

I hear a lot of people call themselves building science geeks, energy nerds, green building dorks, HVAC(Heating, ventilation, and air conditioning). Collectively, the mechanical systems that heat, ventilate, and cool a building. dweebs, weatherization wonks, and policy poindexters. (It's true! Some of them are imaginary people in my mind and some are aliens, but they really do say that.) What I see, though, is that most such people seem to throw these words around without understanding which is which and how dorks and nerds and geeks and dweebs differ.