Musings of an Energy Nerd

If you are a hippie from Taos, New Mexico, you know what an earthship is. It’s an off-grid earth-bermed passive solar home with exterior walls made of old tires packed with dirt.

I installed my solar hot water system about six years ago. It’s a good system. I have two 4’x8’ AE-32 flat-plate collectors (manufactured by Alternate Energy Technologies), a Superstor Ultra stainless-steel tank (at 80 gallons, it’s a little small, but it’s what I could afford), and an El Sid DC pump from Ivan Labs. Since I installed the equipment myself, it cost significantly less than a professionally installed system.

Although I live in the middle of nowhere, in the woods of the Northeast Kingdom of Vermont, my house is only a two-and-a-half-hour drive from the cosmopolitan city of Montreal, Quebec. A few weeks ago I made the drive north to meet a few green builders from Quebec and to attend a green building conference called Ecohabitation 2014.

Montreal is a fun city where it's easy to buy a decent baguette. The city also offers the chance to sample delicious food prepared by Quebecois born in Lebanon, Tunisia, Mexico, India, and many other countries.

Is it possible to describe all of the factors that influence heat and moisture movement through a wall during a single day? Perhaps. We could start by listing the outdoor conditions, including air temperature, relative humidity, wind speed, wind direction, the angle of the sun with respect to the wall (its altitude and azimuth), the cloud thickness, the precipitation rate, and the depth of snow on the ground. Needless to say, many of these factors change from minute to minute.

A balanced ventilationMechanical ventilation system in which separate, balanced fans exhaust stale indoor air and bring in fresh outdoor air in equal amounts; often includes heat recovery or heat and moisture recovery (see heat-recovery ventilator and energy-recovery ventilator). system — for example, a system with a heat-recovery ventilator (HRV(HRV). Balanced ventilation system in which most of the heat from outgoing exhaust air is transferred to incoming fresh air via an air-to-air heat exchanger; a similar device, an energy-recovery ventilator, also transfers water vapor. HRVs recover 50% to 80% of the heat in exhausted air. In hot climates, the function is reversed so that the cooler inside air reduces the temperature of the incoming hot air. ) or an energy-recovery ventilator (ERV(ERV). The part of a balanced ventilation system that captures water vapor and heat from one airstream to condition another. In cold climates, water vapor captured from the outgoing airstream by ERVs can humidify incoming air. In hot-humid climates, ERVs can help maintain (but not reduce) the interior relative humidity as outside air is conditioned by the ERV.) — exhausts stale air from some rooms in a building, while simultaneously introducing fresh outdoor air to other rooms. The best balanced ventilation systems use dedicated ventilation ductwork. Usually, these systems pull exhaust air from damp, smelly rooms — bathrooms and laundry rooms — and introduce fresh air to the rooms where people spend most of their time — bedrooms and the living room.

So-called radiant floors have an excellent reputation. Many customers report that this type of heating system is comfortable and quiet. Moreover, some suppliers of radiant floor materials and equipment claim that these systems can save energy.

In spite of the purported benefits of this type of heating system, few green homes include a radiant floor heating system. This article will explore why.

Do building codes require spray foam insulation to be protected with a layer of drywall or a comparable barrier for fire safety? The answer is yes, usually — but not always.

There is no simple answer to the question, for several reasons. The first reason is that the code is complicated.

The second reason is that the code is poorly written.

The third reason is that the code is subject to interpretation by local code officials.

Building a new home usually requires work by several subcontractors, including electricians, plumbers, and HVAC(Heating, ventilation, and air conditioning). Collectively, the mechanical systems that heat, ventilate, and cool a building. installers. At the end of the job, someone — usually the general contractor — has to verify that all of the specified work has been completed.

Has the water heater been installed? Check.

Air conditioner? Check.

Ducts? Check.

Ventilation system? Check.

All through the 1980s and 1990s, a small band of North American believers worked to maintain and expand our understanding of residential energy efficiency. These were the pioneers of the home performance field: blower-door experts, weatherization contractors, and “house as a system” trainers. At conferences like Affordable Comfort, they gathered to share their knowledge and lick their wounds.

These pioneers understood what was wrong with American houses: They leaked air; they were inadequately insulated; they had bad windows; and their duct systems were a disaster.

Most brands of foil-faced bubble wrap are only 3/8 inch thick or less, and have an R-valueMeasure of resistance to heat flow; the higher the R-value, the lower the heat loss. The inverse of U-factor. of only 1.0 or 1.1. Since the product often costs more per square foot than 1-inch thick rigid foam rated at R-5, why would anyone use bubble wrap as insulation?