Think of a house or building as a system with integrated parts working together as one unit. If one part of the system fails, the entire system is vulnerable and at risk for failure. If we consider the air quality of a building, it is a system that is made up of an air barrier, thermal barrier and air distribution.
The air barrier is the membrane that keeps the exterior separate from the interior. It controls air leakage into and out of the building envelope. A well-sealed home is more healthy and comfortable for its occupants. Air leakage during the hot summer heat can cause excessive moisture in the house; while cooler temperatures during the winter lead to extreme dryness. In addition, leaky homes will have more dust and other irritants floating in the air inside.
Use caulk to fill those small gaps and cracks. Use expanding foam for larger cracks, especially around door jams and windows. Don’t forget to put weather-stripping around the operable parts of doors and windows. Remember to insulate around outlet/ switches and recessed can-lights to stop air leakage.
The thermal barrier is the insulation used to control heating and cooling of a building through ceiling, walls, windows and doors. Insulation keeps the home comfortable while reducing heating and cooling costs. To have efficient thermal barriers the insulation must–
- Create a continuous barrier between the inside conditioned space and the exterior.
- Have a R-value that meets or exceeds specifications.
- Be installed completely in cavities without gaps with minimal compression.
Examples of insulation include spray foam, fiberglass batts, and blow-in cellulose. They increase energy efficiency by allowing the downsizing of the heating and cooling system equipment.
Air distribution is made up of HVAC (heating, ventilating and air conditioning) duct work. The goal is to have a 100% tight seal with 0% leakage. In Florida, homeowners who upgrade their air conditioning systems can qualify to receive a $1,500 rebate. To qualify the duct leakage report (after the new installation) must be no more than 15% leakage. The air conditioning unit must also have the Energy Star rating.
When homes are tightly sealed they reduce natural air flow ventilation. Mechanical ventilation is then required to get fresh outside air in to prevent furnishings, building materials and household chemical air pollutants to accumulate inside the home. There are three ventilation systems to choose from –
- Continuous ventilation systems distribute low volumes of fresh air throughout a building and move stale air out.
- Energy recovery ventilators (ERVs) are used in high humidity climates. They help control the humidity levels by lowering the moisture content of fresh air coming in and reducing the load on air conditioners.
- Heat recovery ventilators (HRVs) are air-to-air exchangers. They are similar to ERVs but do not control moisture. HRVs transfer heat energy from one air stream to the other, they use inside air to pre-heat or pre-cool incoming outside air.
Passive measures can also help reduce power and increase efficiency.
- Monitor light control. Use powered window treatments that control light and solar shades that reflect ultraviolet rays out.
- Use light colors and materials to reflect light (darker colors will absorb heat).
- Use light shelves. They allow natural sunlight into a room, but will redirect and diffuse the light in a room.
- Use LED (light-emitting diode) lights. They use less energy, have longer life and do not generate heat.
The following Energy Efficiency Pyramid published by Minnesota Power shows the relationship between investment complexity and what an end user can do to increase energy efficiency in their home.
If you incorporate the air barrier, thermal barrier and air distribution system components that work at 100%, I am sure your home will become more energy efficient and at lower costs. Good luck.