What is Comfortable?

InterNACHI has determined that a comfortable, safe, and energy-efficient home requires:

• A fully insulated thermal envelope or thermal boundary.
• A well-sealed air barrier: Since air carries heat and moisture, the condition of the air barrier plays a major role in the movement of heat and moisture through the building. It also affects indoor air quality (IAQ).
• Thermal and air boundaries that are continuous and in contact with one another. The motto is, “seal tight, insulate right.”
• Efficient, properly sized equipment to condition the living space and heat water — bigger is not better. For example, oversized air-conditioners make a house cold and clammy, and short cycle times produce problems down the road. Moisture in the air condenses on building surfaces instead of on the condenser coil, which can cause mold and rot. This course focuses on the first three factors.
• A well-designed and balanced air distribution system.
• Healthy indoor air quality: IAQ is a key health and safety concern. Home energy contractors should test for carbon monoxide (CO) levels, backdrafting, and mold and moisture issues to make sure they leave all homes safe for the residents.

Energy Sources Can be Categorized As Renewable or Nonrenewable

When we use electricity in our home, the electrical power was probably generated by burning coal, by a nuclear reaction, or by a hydroelectric plant at a dam. Therefore, coal, nuclear and hydro are called energy sources. When we fill up a gas tank, the source might be petroleum or ethanol made by growing and processing corn.

Energy sources are divided into two groups: renewable (an energy source that can be easily replenished) and nonrenewable (an energy source that we are using up and cannot recreate). Renewable and nonrenewable energy sources can be used to produce secondary energy sources including electricity and hydrogen.
Renewable Energy

Renewable energy sources include:

• Solar energy from the sun, which can be turned into electricity and heat
• Wind
• Geothermal energy from heat inside the earth
• Biomass from plants, which includes firewood from trees, ethanol from corn, and biodiesel from vegetable oil
• Hydropower from hydroturbines at a dam