Increasing Home Energy Efficiency
by Nick Gromicko and Kenton Shepard
InterNACHI advises that energy-efficient homes require less energy to perform household functions than homes that are less energy-efficient. There are many adjustments that homeowners can make to reduce the amount of energy required by their homes.
Interesting facts about energy consumption in the United States and Canada:
- The United States is the world’s largest consumer of energy, and the world’s seventh largest consumer of energy per capita.
- Canada consumes more energy per capita than the United States.
- Buildings account for 72% of all energy consumed in the United States.
- 18% of all emissions in the United States comes from operating homes.
- In the average household, the TV is left on stand-by for 17 hours per day.
Why make your home more energy-efficient?
- Federal, state, utility and local jurisdictions' financial incentives, such as tax breaks, are very advantageous in most parts of the U.S.
- It saves money. It costs less to power a home that has been converted to be more energy-efficient.
- It increases indoor comfort levels.
- It reduces our contributions to climate change. Many scientists now believe that excessive energy consumption contributes significantly to global warming.
- It reduces pollution. Conventional power production introduces pollutants into the air that find their way into the soil and water supplies.
Heating and Cooling
As much as half of the energy used in homes goes toward heating and cooling.
The following are a few ways that energy bills can be reduced through adjustments to the heating and cooling systems:
Appliances and Electronics
- Add insulation to the building envelope (walls, floors and ceiling) to bring the home up to the U.S. Department of Energy (DOE)-recommended limits for the climate zone in which the home is located.
- Insulate heating ducts. Up to 40% of energy can be lost in uninsulated heating ducts routed through unheated space. This means that up to 45 cents of every dollar spent on heating can be wasted.
- Install a ceiling fan. Ceiling fans can be used in place of air conditioners, which require large amounts of energy.
- Periodically replace air filters in air conditioners and heaters.
- Set thermostats to an appropriate temperature. Specifically, they should be turned down at night and when no one is home. In most homes, about 2% of the heating bill will be saved for each degree that the thermostat is lowered for at least eight hours each day. Turning down the thermostat from 75° F to 70° F, for example, saves about 10% on heating costs.
- Install a programmable thermostat. A programmable thermostat saves money by allowing heating and cooling appliances to be automatically turned down during times at which no one is home and at night. Programmable thermostats contain no mercury and, in some climate zones, can save hundreds of dollars per year in energy costs.
- Install a wood stoves or a pellet stove. These are more efficient sources of heat than furnaces.
- At night, curtains drawn over windows will better insulate the room.
Appliances and electronics are responsible for about 20% of household energy bills in a typical U.S. home.
The following are tips that will reduce the required energy of electronics and appliances:
- Refrigerators and freezers should not be located near the stove, dishwasher or heat vents, or exposed to direct sunlight. Exposure to warm areas will force them to use more energy to remain cool.
- Computers should be shut off when not in use. If unattended computers must be left on, their monitors should be shut off. According to some studies, computers account for approximately 3% of all energy consumption in the United States.
- Use efficient “Energy Star”-rated appliances and electronics. These devices, approved by the DOE and the EPA’s Energy Star program, range from TVs, home theater systems, DVD players, CD players, receivers, speakers and more. According to the EPA, if just 10% of homes used energy-efficient appliances, it would reduce carbon emissions by the equivalent of 1.7 million acres of trees.
- Chargers, such as those for laptops and cell phones, consume energy when they are plugged in. When they are not connected to electronics, chargers should be unplugged so they don't continue to draw current.
- Laptop computers consume considerably less electricity than desktop computers.
The average household dedicates 11% of its energy budget to lighting. Traditional incandescent lights convert approximately only 10% of the energy that they consume into light, while the rest becomes heat. The use of new lighting technologies, such as light-emitting diodes (LEDs) and compact fluorescent lamps (CFL), can reduce energy use required by lighting by 50% to 75%. Advances in lighting controls offer further energy savings by reducing the amount of time lights are on but not being used.
Here are some facts about CFLs and LEDs:
- CFLs use 75% less energy and last about 10 times longer than traditional incandescent bulbs.
- LEDs last even longer than CFLs and consume less energy.
- LEDs have no moving parts and, unlike CFLs, they contain no mercury
Daylighting is the practice of using natural light to illuminate the home's interior.
It can be achieved using the following approaches:
- skylights. It’s important that they be double-pane or they may not be cost-effective. Flashing skylights correctly is key to avoiding leaks.
- light shelves. Light shelves are passive devices designed to bounce light deep into a building. They may be interior or exterior. Light shelves can introduce light into a space up to 2½ times the distance from the floor to the top of the window, and advanced light shelves may introduce four times that amount.
- clerestory windows. Clerestory windows are short, wide windows set high on the wall. Protected from the summer sun by the roof overhang, they allow winter sun to shine through for natural lighting and warmth.
- light tubes. Light tubes use a special lens designed to amplify low-level light and reduce light intensity from the midday sun. Sunlight is channeled through a tube coated with a highly reflective material, then enters the living space through a diffuser designed to distribute light evenly.
An enormous amount of energy is wasted while cooking.
The following recommendations and statistics illustrate less wasteful ways of cooking:
- Convection ovens are more efficient that conventional ovens. They use fans to force hot air to circulate more evenly, thereby allowing food to be cooked at a lower temperature. Convection ovens use approximately 20% less electricity than conventional ovens.
- Microwave ovens consume approximately 80% less energy than conventional ovens.
- Pans should be placed on the correctly-sized heating element or flame.
- Lids make food heat more quickly than pans that do not have lids.
- Pressure cookers reduce cooking time dramatically.
- When using conventional ovens, food should be placed on the top rack. The top rack is hotter and will cook food faster.
Leakage Through the Building Envelope
Sealing holes and cracks in the home’s envelope helps reduce drafts, moisture, dust, pollen and noise. A tightly sealed home can improve comfort and indoor air quality while reducing utility bills. Tightening the home reduces the number of air changes per hour.
The following are some common places where leakage may occur:
- electrical outlets;
- mail slots;
- around pipes and wires;
- wall- or window-mounted air conditioners;
- attic hatches;
- fireplace dampers;
- weatherstripping around doors;
- window frames; and
- switch plates.
Strategies for filling cracks:
Windows and Doors
- Caulk can be used to fill small gaps. Caulk can be obtained at hardware stores.
- Expandable foam can be used to fill larger gaps.
- Foam gaskets can be used to seal electrical outlets.
About one-third of the home's total heat loss usually occurs through windows and doors.
The following are ways to reduce energy lost through doors and windows:
Indoor Water Conservation
- Seal all window edges and cracks with rope caulk. This is the cheapest and simplest option.
- Windows can be weatherstripped with a special lining that is inserted between the window and the frame. For doors, weatherstrip around the whole perimeter to ensure a tight seal when closed. Install quality door sweeps on the bottom of the doors, if they aren't already in place.
- Install storm windows at windows with only single panes. A removable glass frame can be installed over an existing window.
- If existing windows have rotted or damaged wood, cracked glass, missing putty, poorly fitting sashes, or locks that don't work, they should be repaired or replaced.
The following systems can be installed to conserve water usage in homes:
- low-flow shower heads. They are available in different flow rates, and some have a pause button which shuts off the water while the bather lathers up.
- low-flow toilets. Toilets consume 30% to 40% of the total water used in homes, making them the biggest water users. Replacing an older 3.5-gallon toilet with a modern, low-flow 1.6-gallon toilet can reduce usage an average of two gallons-per-flush (GPF), saving 12,000 gallons of water per year. Low-flow toilets usually have "1.6 GPF" marked on the bowl behind the seat or inside the tank.
- vacuum-assist toilets. These types of toilets have a vacuum chamber, which uses a siphon action to suck air from the trap beneath the bowl, allowing it to quickly fill with water to clear waste. Vacuum toilets are relatively quiet.
- dual-flush toilets. Dual-flush toilets have been used in Europe and Australia for years, and are now gaining in popularity in the U.S. Dual-flush toilets let you choose between a 1-gallon (or less) flush for liquid waste, and a 1.6-gallon flush for solid waste. Dual-flush 1.6-GPF toilets reduce water consumption by an additional 30%.
Solar water heating first became popular in the 1970s when federal, state and utility incentives encouraged their installation, as is happening again now. Inspectors will see many of these older systems still in place but no longer working. In practice, inspectors will encounter a wide variety of system configurations and components, and recommending a specialist inspection is a good idea in order to pass on liability. These systems can be expensive. The idea is fairly simple. Solar insolation heats a circulating fluid which transfers its heat to a storage tank from which home hot water can be drawn, either directly to plumbing fixtures, or to supply pre-heated water to boilers or hot water heaters.
Various types of solar-thermal heating can be installed, such as:
- evacuated tube collectors;
- flat-plate collectors; and
- parabolic through-collectors.
In summary, there are a variety of adjustments to the home that homeowners can make to increase the energy efficiency of their homes.