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HOME AUDIT TERMINOLOGY
Building Envelope
Also called the “thermal boundary” or “shell,” the building envelope is made up of the outer walls, ceiling, windows, doors and floors of the house. Air leaks through the envelope and inadequate insulation are two common problems in many homes, both of which lead to discomfort and high energy bills.
Blower Door Test
Blower Door Testing determines the air tightness of a building envelope by affixing a special fan apparatus in an exterior doorway and creating a pressure change by blowing air out of the house. Gauges measure the demand on the fan to maintain the pressure, which determines the leakiness of the building and the air changes per hour (ACH), while the pressure change makes it possible to find hidden air leakage sites.
ACH
Stands for Air Changes per Hour, which is the number of times in one hour that the air inside a house is completely replaced with outside air.
Duct Blaster Test
A duct blaster combines a small fan and a pressure gauge to pressurize the duct system in a house in order to accurately measure air leakage in the ductwork. This test is similiar to a pressure test of a plumbing system. Duct leakage can increase heating and cooling costs over 30% and contribute to comfort, health and safety problems.
HEATING, VENTILATION AND COOLING TERMINOLOGY
HVAC
An abbreviation for the heating, ventilation, and air-conditioning system; the system or systems that condition air in a building.
System Capacity
Measurement of the total amount of heat or cooling your furnace, heat pump or air conditioner can produce in one hour. This amount is reported in Btu/hr on the nameplate of your equipment.
EER
Energy Efficiency Ratio, EER, is the instantaneous measurement of the cooling efficiency of your air conditioner or heat pump. The higher the EER for your air conditioner or heat pump, the more efficient it is.
SEER
The Seasonal Energy Efficiency Ratio, SEER, measures the average cooling efficiency of your air conditioner or heat pump over the entire cooling season.
Programmable Thermostat
A thermostat for your heating and/or cooling equipment with the ability to record and automate different temperature settings for different times. Programmable thermostats can be electronic or mechanical.
INSULATION TERMINOLOGY
Insulation
Any of a number of substances that resists the transfer of heat, generally by incorporating small pockets of air. Insulation is rated in terms of thermal resistance, called R-value, which indicates the resistance to heat flow. The higher the R-value, the greater the insulating effectiveness. The R-value of thermal insulation depends on the type of material, its thickness and density.
U-Value
U-value is a measurement of heat flow. The lower the U-value, the more slowly the material transfers heat in and out of your home.
R-Value
R-value is a measurement of heat resistance. It is the inverse of the U-value, so the higher the R-value, the better the insulation resists heat transfer. Many factors can affect the R-value of insulation, including the type and age of the insulation.
Radiation
The transfer of heat directly from one surface to another (without the intermediate air acting as a transfer mechanism).
Radiant Barrier
Thin layers of highly reflective material which reduce heat transfer from thermal radiation across the air space between the roof and the attic floor.
Conduction
The transfer of heat through solid material.
Convection
The transfer of heat by air flow.
INSULATION DESCRIPTIONS
Fiberglass
Spun from molten glass and pure white in its virgin state, fiberglass is the most familiar type of insulation. Additives and binders often color the fiberglass, pink and yellow being the most common. Fiberglass comes in rolls, batts and as loose insulation which is blown into place.
Rockwool
Dirty grey, although the color can range through green and brown as well, rockwool looks like old wool with dark flecks, and you can often find what looks like sand or small pebbles underneath the insulation. Like fiberglass, rockwool is spun from the slag from refining metals. The debris that settles underneath the insulation is condensed droplets of metal, remnants of the slag.
Cellulose
Insulation made from wastepaper such as used newspaper and boxes, cellulose is shredded into small particles, and chemicals that provide resistance to fire and insects are added. Cellulose insulation is dusty and brown with flat particles on which you can frequently find legible print.
Perlite
A white and gravelly yet extremely light material, perlite is the same as is found in garden centers and used as part of potting mixtures. Perlite is no longer used as an insulating material, except for the occasional do-it-yourselfer, although it is not uncommon to find it in existing homes.
Vermiculite
Made from expanded mica, a mineral, the vermiculite used as insulation is identical to the material found in garden centers. Like perlite, it is generally no longer used for insulation, although again, it can sometimes be found in existing homes.
Rigid Boards
Fibrous materials or plastic foams pressed or extruded into board-like forms, rigid boards provide thermal and acoustical insulation, strength with low weight, and coverage with few heat loss paths.
WINDOW TERMINOLOGY
Tinted Glazing
Tinted glass and tinted window films reduce the amount of solar heat entering the building. The shading coefficient (SC) of a window is the amount by which the window reduces heat gain. The lower the shading coefficient, the less solar heat is admitted. New glazings reduce the heat gained by your house without reducing visibility as much as older tinted glass and films. Visible light transmittance (VLT) is the measure of the amount of light that comes through the window. (The average clear, untinted glass window has a VLT of 84%, not 100% as some might suspect.)
Frame Material
Wood, vinyl or fiberglass frames conduct less heat than aluminum frames, increasing window efficiency.
LIGHTING TERMINOLOGY
Lamp
The lighting industry uses the term lamp to refer to the source of light, the light bulb itself, not the fixture where the light bulb is located.
Incandescent Lamp
The most common source of light, incandescent lamps are glass bulbs with a filament inside. Approximately 90% of the energy consumed by an incandescent lamp is given off as heat rather than light.
Fluorescent Lamp
Up to five times more efficient than incandescent lamps, fluorescent lamps last up to twenty times longer. They require a special fixture. Electronic ballast fluorescents are a new efficient improvement over the traditional magnetic ballast fluorescents. Fluorescent Lamps are available as straight tubes, U-shaped tubes, circular tubes and compact fluorescent lamps.
Compact Fluorescent Lamps (CFLs)
These fluorescent lamps are small and are designed to fit in regular lamp sockets. They do not require a special fixture. The electronic ballast-based fluorescents are more efficient, and produce better light than the older magnetic ballast models.
Use fans. Ceiling and portable fans use very little electricity. By circulating air, they make the house feel cooler, which allows you to raise your thermostat setting while still maintaining the same comfort as the lower setting. But remember: Ceiling fans only cool people, not the room- so when you leave the room, turn the ceiling fan off. (Use low wattage CFLs in the ceiling fan light fixture for more energy savings.)
Set your thermostat at 76° in the summer and 68° in the winter. Each degree cooler or warmer will decrease your energy use by 6 to 8%. For instance, setting your thermostat at 76° instead of 72° in the summer will use close to 30% less energy!
If you have central air conditioning, do not close vents in unused rooms. This can increase pressure and cause leaks in your ducts.
Clean or replace your HVAC filters at least once a month. Dirty filters make your system work harder and run longer than necessary, as well as encourage the buildup of mold and mildew, making cleaning more difficult.
Turn up the thermostat when you leave the house or go to sleep. It's a common misperception that it takes more energy to cool off (or heat up) a house than it takes to keep it cool all the time. It's best to only cool (or heat) a house as much as necessary, based on occupants and time of day. Turning up the thermostat in summer (or down in winter) will always save energy.
Install a programmable thermostat. Programmable thermostats allow you to automatically control your home's temperature settings when you're away or sleeping. When used properly, a programmable thermostat with its four temperature settings can save significant energy and costs. It’s easy to forget to adjust the thermostat when leaving the house or going to bed, and it takes time for the house to cool off (or warm up) once a manual thermostat is adjusted, which can be uncomfortable. Here's where a programmable thermostat pays off, because it automatically adjusts the temperature when your home is empty and when you go to sleep, then it brings the temperature back to your chosen comfort level by the target times you’ve set for returning home or getting up in the morning.
Consider new high efficiency air conditioners and heat pumps. They use up to 40% less electricity than older models for the same amount of running time.
Make sure all air registers are clear of furniture so that air can circulate freely.
If you have window a/c units, closing off unused rooms will reduce cooling costs and increase comfort.
Replace some of your incandescent bulbs with compact fluorescents. Each ENERGY STAR qualified compact fluorescent light bulb (CFL) will save about $30 over its lifetime and pay for itself in about 6 months. It uses 75% less energy and lasts about 10 times longer than an incandescent bulb. New technology has created CFLs with no buzzing sound and in a variety of styles and shades, but if you can’t find CFLs that suit you perfectly, at least consider replacing the bulbs in areas like your pantry, laundryroom, utility room, garage and porch.
Install dimmer switches. A dimmer switch is a type of light switch that allows a light to be dimmed or brightened continuously. The dimmer the light is, the more energy you save. Dimmer switches not only save you money on the energy used to light a bulb, they also save you money by increasing the lifespan of the bulb. Available at most hardware stores for about $8 to $20.
Turn the lights off if you are leaving the room for more than a couple of seconds. This saves energy with both fluorescent and incandescent bulbs. Incandescent lights do not require additional energy to start up. Turning lights on and off frequently does slightly shorten the lifetime of the bulbs, but you will have to replace the bulbs less frequently if they are not running all day long.
Install motion detecting switches in garage and laundry/utility rooms. These will turn the lights on when they sense any motion and automatically turn lights off when they do not sense motion for some period of time (set by you). Not only far more convenient, these will save you money and life on your bulbs. (About $25 to $30 at hardware stores.) Be super efficient by using them in combination with CFLs!
Substantially reduce your standby power consumption. Use a power strip as a central “turn off” point when you are done using electronic and IT equipment. In the average home, 75% of the electricity used to power home electronics is consumed while the products are turned off because most tv’s, dvd players, battery chargers, computers and related equipment use a small amount of electricity even when off. (The transformer in the AC adapter for a laptop draws power continuously, even when the laptop is not plugged into the adapter.) Standby power consumption can be eliminated by unplugging the equipment or by using a power strip, which allows you to completely disconnect from the power source.
Enable power management features on your home computer and monitor. You can save energy by avoiding using a screensaver when your computer monitor is not active. Office equipment that is set automatically to switch to sleep mode not only uses less energy, it helps the equipment last longer and run cooler, allowing for savings on air conditioning, as well. Even better, turn off your personal computer when you're away from it for 20 minutes or more, and both the CPU and the monitor if you will be away for two hours or more. (Don't worry about wear on the computer from turning it on and off repeatedly. This was once a problem in the early days of personal computers, but now your computer undergoes more wear from running constantly than from being turned off when not in use.)
Set your water heater thermostat to 120° F. Savings resulting from turning down your water heater temperature are based on two components: reduced standby losses (heat lost from water heater into surrounding area); and reduced consumption (from water demand or use in your home). Set too high (like at 140° F), your water heater can waste more than $400 annually in standby heat and demand losses.
Close your fireplace’s flue damper tightly when not in use to keep air-conditioned air from escaping from the house. A chimney is designed to remove by-products from a fire by creating a draft. The draft also pulls air from your home up the chimney - air that you've paid to cool or heat. Even without a fire in the fireplace, there still will be a draft in the chimney as long as there is a temperature difference between indoors and out. Closing the damper will keep air conditioned (or warmed) air in the living space where it belongs.
Seal any holes around your electrical outlets with inexpensive outlet gaskets.
Use the right sized pot on stove burners. A 6" pot on an 8" burner wastes over 40% of the burner's heat. Also, cover pots and pans to help you cook more efficiently and keep your kitchen cooler.
Use your microwave or toaster oven to reheat or cook small portions. You can reduce cooking energy by as much as 80% when using your microwave for small portions. This also helps save on a/c costs in summer, since less heat is generated than using your stove or oven.
Use vent fans in bathrooms. Make sure you have a properly sized ENERGY STAR-qualified ventilation fan to control moisture in the air, make sure it works and USE IT every time you shower or bathe. It will reduce humidity and heat in your home, as well as control mold and mildew growth. Also be sure the fan duct leads to the outdoors to prevent moisture problems. Run your fan for 5 minutes after showering, but don’t forget about it and leave it running – the vent fan not only pulls humidity from a room, it also pulls air-conditioned air and takes electricity to run. Ideally, install a timer-switch on vent fans in bathrooms.
A new low-flow showerhead can save up to $145 each year on electricity.
Wash and dry full loads of laundry. If you are washing a small load, use the appropriate water-level setting.
Wash your laundry with cold water whenever possible. Hot water heating accounts for about 90% of the energy your machine uses to wash clothes — only 10% goes to electricity used by the washer motor.
Clean the lint filter in the dryer after every load to improve air circulation.
Don't over-dry your clothes. Settings like “Very Dry” or “Less Dry” utilize your dryer’s moisture sensor, saving you the guesswork and energy wasted with overdrying.
Dry towels and heavier cottons in a separate load from lighter-weight clothes.
Periodically inspect your dryer vent to ensure it is not blocked. This will save energy and may prevent a fire.
Air dry dishes instead of using your dishwasher's drying cycle. Save water by scraping dishes instead of rinsing them before loading in the dishwasher. Rinsing dirty dishes before loading your dishwasher uses a lot of water and energy. Most dishwashers today can thoroughly clean dishes that have had food scraped, rather than rinsed, off — the wash cycle and detergent take care of the rest. Only run your dishwasher when you have a full load.
Shade outside a/c units and clear the area. A/C units shaded by trees or other means work more efficiently, using up to 10% less electricity. Keep debris and high grass away from the condenser to avoid blockage of airflow to the unit, which makes it work harder and run longer.
Clean your a/c’s condenser/evaporator coils at the beginning of the season. Clean coils lower your energy costs, extend the unit's life and provide cleaner air. (The fin coils on an outside AC unit can be washed with a hose. Coils on inside units may be difficult to get to and may require a trained technician.)
Seal your home’s entire envelope. Sealing your home's entire envelope is one of the most cost-effective ways to reduce your energy bill and improve your comfort. Home sealing reduces uncomfortable drafts and helps avoid moisture problems by sealing holes, cracks, and gaps. Done right, home sealing could save you up to 10% on your home energy bill.
Caulk and weather-strip around windows and door frames that leak air. If replacing windows, choose ENERGY STAR qualified models designed for your area. With proper installation to ensure all gaps are sealed around them, ENERGY STAR qualified windows will reduce energy costs, help improve your comfort, cut drafts, and reduce fading of interior furnishings.
IN THE WINTER:
Did you know your ceiling fan can help improve your comfort and efficiency even in cold weather? Most fans have a switch that allows you to reverse the motor and operate the ceiling fan at a low speed in the counter-clockwise direction. This produces a gentle updraft, which forces warm air near the ceiling down into the living space.
Be sure to insulate room air conditioners from the outside with a tight-fitting a/c unit cover. Available at your local home improvement center or hardware store, an a/c cover helps keep heated air from escaping to the outside.