Most people don’t know how easy it is to make their homes run on less energy, and here at InterNACHI, we want to change that. Drastic reductions in heating, cooling and electricity costs can be accomplished through very simple changes, most of which homeowners can do themselves. Of course, for homeowners who want their homes to take advantage of the most up-to-date knowledge and systems in home energy-efficiency, InterNACHI energy auditors can perform in-depth testing to find the best energy solutions for your particular home.

Why make your home more energy efficient? Here are a few good reasons:

    * 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 impact on climate change. Many scientists now believe that excessive energy consumption contributes significantly to global warming.
    * It reduces pollution. Conventional power production introduces pollutants that find their way into the air, soil and water supplies.

1. Find better ways to heat and cool your house.
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:

    * Install a ceiling fan. Ceiling fans can be used in place of air conditioners, which require a large amount 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 that no one is home and at night. Programmable thermostats contain no mercury and, in some climate zones, can save up to $150 per year in energy costs.
    * Install a wood stove or a pellet stove. These are more efficient sources of heat than furnaces.
    * At night, curtains drawn over windows will better insulate the room.

2. Install a tankless water heater.
Demand water heaters (tankless or instantaneous) provide hot water only as it is needed. They don't produce the standby energy losses associated with storage water heaters, which will save on energy costs. Demand water heaters heat water directly without the use of a storage tank. Therefore, they avoid the standby heat losses required by traditional storage water heaters. When a hot water tap is turned on, cold water travels through a pipe into the unit. Either a gas burner or an electric element heats the water. As a result, demand water heaters deliver a constant supply of hot water. You don't need to wait for a storage tank to fill up with enough hot water.

 

What is a Blower Door?
Inspectors should become familiar with blower doors, as they can be a valuable tool in energy audits.

A blower door is a powerful, variable-speed fan that can be temporarily mounted into an exterior door frame to provide controlled air flow for analysis.  The way that air flows through a building can have a serious impact on air quality, comfort and energy expenses.  The use of a blower door allows air flow through a structure, and the resulting loss of heat can be immediately quantified, providing a way to pinpoint the location of air leaks.

Blower doors were originally developed in the 1970s for use as a research tool.  As technology has evolved, allowing for the development of more portable equipment, blower doors have transitioned into use as a valuable field tool, as well.  The first portable blower doors weighed as much as 200 pounds and took up quite a bit of space, and were also very expensive.  Today, they are much more affordable and are built lighter and smaller.  The reduced set-up time allowed by their more compact designs has led to the standard use of blower doors as part of energy audits for measuring air flow.

How It WorksWhen air pressure and air flow are controlled and measured, they can provide data about how airtight a building is.  The three variables involved are pressure, flow and holes or leaks.  A change in one of these factors will produce a change in at least one other factor.  Since the goal of a blower door test is to locate air leaks in the building envelope, data regarding air pressure and flow can provide information about the holes, which may otherwise be tough to find.

The blower door utilizes controlled differences in air pressure to collect data.  Once installed in an exterior door frame, the air pressure inside a building can be changed in relation to the outside pressure by forcing air into or out of the interior.  The difference in pressure forces air through holes or leaks in the building envelope.  The pressure and air flow are measured by gauges, which are part of the blower door equipment.  By measuring the pressure and air flow in relation to each other, the airtightness of the building envelope can be quantified.  The amount of air flow needed to create a change in pressure increases as the airtightness of the building envelope decreases.  A well-sealed building requires less air flow to generate a change in pressure.

Finding the Problems

During a blower door test, the interior air pressure needed to be maintained in order to gather useful data is 50 pascals, which is roughly equal to the pressure created when a 20-mph wind hits the building.  The blower door equipment has a gauge to indicate when this pressure has been achieved, as well as a gauge to indicate the cubic feet per minute (CFM), which is the standard unit of measure for air flow.  Air flow in a well-sealed building will generally be less than 1,500 CFM at 50 pascals.  Air flow above 4,000 CFM would be considered leaky.  This is valuable data that can be acquired in about half an hour with the use of a blower door.

Since the blower door forces air through cracks and holes, the locations of the leaky spots can be identified.  The draft of air entering through the holes can often be felt with the hand.  Smoke and infrared imaging can also be employed to locate smaller, more subtle leaks.  It is often assumed, especially by homeowners, that poorly sealed windows and doors are the major culprits of air leaks.  In reality, leaks in other areas are usually much more significant.  The difference in air pressure between the interior and the exterior is greater both at ground level and up high, so leaks in basements and crawlspaces, as well as in attics, are the most important to locate.

When looking for air leaks, check through basement rim joists, holes for plumbing traps under tubs and showers, cracks between finish flooring and baseboards, utility chases, plumbing vent-pipe penetrations, kitchen soffits, fireplace surrounds, recessed can lights, and cracks between partition top plates and drywall.  These are all common places where significant leaks can develop.

Accounting for Outside FactorsWind and temperature can have an effect on the test data.  Wind blowing on the outside of the building can add to pressure differences between the interior and exterior.  It can also affect the flow rate of the blower fan.  It is best not to conduct blower door tests in windy conditions.  But if wind is not severe, tests can be conducted at multiple points in the building and then averaged together.

Differences in temperature can create differences in pressure.  Accounting for a baseline stack-effect pressure will ensure that the test results are not skewed.  The stack-effect pressure is a function of the height of the building and the difference in temperature from the interior to the exterior.  A 15-foot tall building with a 50º-temperature difference between the inside and outside will have a 5-pascal pressure difference from the top of the building to the bottom.  Some blower door equipment has a gauge with a built-in baseline feature, so this difference can be easily determined at the outset of the test.

Temperature and barometric pressure affect both air density and viscosity, which is its resistance to flow.  Because of this, an adjustment for density is required.  Some software packaged with blower door equipment is designed to make these calculations, and if it is not available during the test, the manual supplied with the equipment should have information about making the necessary adjustments and applying it to the results.

Preparation and Safety

In order to ensure accurate results, as well as safe conditions for performing the test, some preparation is necessary before beginning.  Any fireplaces or stoves used for heating should not be operating, and all furnaces and pilot lights should be turned off.  There should be no open flames anywhere indoors.  Ashes in fireplaces or stoves should be removed so they do not get sucked into the building.  Dampers should be closed.  Every door and window must be closed tightly so that air flowing through them does not affect the test, while all interior doors should be left open.

If there is a basement, it must be determined whether this area is to be considered part of the building envelope for testing purposes.  Generally, if there is heat in the basement, even if only because the furnace is located there, it will be considered part of the envelope, and access to it should be left open during the test.  Sometimes, the test may be done both ways -- with the basement access open and with it closed, and this is quick and simple to accomplish.

Since blower door testing is a standard tool used during an energy audit, it is helpful for inspectors to understand how the test works.  Knowing a bit about the outside factors that can influence the results will ensure that the test is performed correctly.  Setting up the equipment properly will ensure that testers and occupants are safe, and that the testing and results are accurate.

A/C: An abbreviation for air conditioner or air conditioning.

A/C Circuit: Alternating Current. The flow of current through a conductor first in one direction, then in reverse. It is used exclusively in residential and commercial wiring because it provides greater flexibility in voltage selection and simplicity of equipment design.

A/C Condenser: The outside fan unit of the air conditioning system. It removes the heat from the Freon gas and turns the gas back into a liquid and pumps the liquid back to the coil in the furnace.

A/C Disconnect: The main electrical ON-OFF switch near the A/C condenser.

Above Grade Wall: A wall more that is mostly above grade and enclosing conditioned space.

ABS: (Acrylonitrile butadiene styrene) Rigid black plastic pipe used only for drain lines.

Absolute Humidity: Amount of moisture in the air, indicated in grains per cubic foot

Accelerator: Any material added to stucco, plaster or mortar which speeds up the natural set.

Access: That which enables a device, appliance or equipment to be reached.

Access Panel: An opening in the wall or ceiling near the fixture that allows access for servicing the plumbing/electrical system.

Accessibility: Level of access a building offers people with disabilities.

Accessible: Can be approached or entered by the inspector safely, without difficulty, fear or danger.

Accessory Structure: An additional building to the primary building.

Acre: 43,560 square feet.

Acrylic: A glassy thermoplastic material that is vacuum-formed to cast and mold shapes that form the surface of fiberglass bathtubs, whirlpools, shower bases, and shower stalls.

Activate: To turn on, supply power, or enable systems, equipment, or devices to become active by normal operating controls. Examples include turning on the gas or water supply valves to the fixtures and appliances and activating electrical breakers or fuses.

Actual Dimension (Lumber): The exact measurement of lumber after it has been cut, dried and milled.

Actual Knowledge: The knowledge possessed by an individual as opposed to that discovered through document review.

Adaptor: A fitting that unites different types of pipe together, e.g. ABS to cast iron pipe.

Addition: An extension or increase in the conditioned space of a building.

Adhesion: The property of a coating or sealant to bond to the surface to which it is applied.

Adhesive Failure: Loss of bond of a coating or sealant from the surface to which it is applied.

Adverse Conditions: Conditions that may be dangerous for the inspector and may limit the walk-through survey portion of the inspection.

Adversely Affect: Constitute, or potentially constitute, a negative or destructive impact.

Aerator: An apparatus that mixes air into flowing water. It is screwed onto the end of a faucet spout to help reduce splashing.

Aggregate: Crushed stone, slag or water-worn gravel that comes in a wide range of sizes which is used to surface built-up roofs.

Air Chamber: A vertical, air-filled pipe that prevents water hammer by absorbing pressure when water is shut off at a faucet or valve.

Air Duct: Ducts, usually made of sheet metal, that carry cooled or heated air to all rooms.

Air Filters: Adhesive filters made of metal or various fibers that are coated with an adhesive liquid to which particles of lint and dust adhere. These filters will remove as much as 90% of the dirt if they do not become clogged. The more common filters are of the throwaway or disposable type.

Air Infiltration: The amount of air leaking in and out of a building through cracks in walls, windows and doors.

Air Intake: An opening in a building's envelope whose purpose is to allow outside air to be drawn in to replace inside air.

Air Space: The area between insulation facing and interior of exterior wall coverings. Normally a 1" air gap.

Air-Dried Lumber: Lumber that has been piled in yards or sheds for any length of time. For the United States as a whole, the minimum moisture content of thoroughly air dried lumber is 12 to 15 percent and the average is somewhat higher. In the South, air dried lumber may be no lower than 19 percent.

Airway: A space between roof insulation and roof boards provided for movement of air.

Aisle: An exit access component that provides a path of egress travel.

Alarm Signal: A signal indicating an emergency, such as a fire, requiring immediate action.

Alarm System: Warning devices, installed or free-standing, including but not limited to: carbon monoxide detectors, flue gas and other spillage detectors, security equipment, ejector pumps and smoke alarms.

Algae: Microorganisms that may grow to colonies in damp environments, including certain rooftops. They can discolor shingles. Often described as "fungus."

Alligatoring: A condition of paint or aged asphalt brought about by the loss of volatile oils and the oxidation caused by solar radiation. Causes a coarse checking pattern characterized by a slipping of the new paint coating over the old coating to the extent that the old coating can be seen through the fissures. "Alligatoring" produces a pattern of cracks resembling an alligator hide and is ultimately the result of the limited tolerance of paint or asphalt to thermal expansion or contraction.

Allowable Span: The distance between two supporting points for load bearing lumber such as joists, rafters or a girder.

Allowance(s): A sum of money set aside in the construction contract for items which have not been selected and specified in the construction contract. Best kept to a minimum number and used for items whose choice will not impact earlier stages of the construction. For example, selection of tile because flooring may require an alternative framing or underlayment material. (Also, money that your parents give you as a child.)

Alteration: Any construction or renovation to an existing structure other than a repair or addition. Also, a change in a mechanical system.

Aluminum Wire: A conductor made of aluminum for carrying electricity. Aluminum is generally limited to the larger wire sizes. Due to its lower conductivity, aluminum wire smaller than No. 12 is not made. Aluminum is lighter and less expensive than copper, but does not conduct as well. It also breaks easily.

Amortization: A payment plan by which a loan is reduced through monthly payments of principal and interest.

Ampacity: Refers to the how much current a wire can safely carry. For example, a 12 gauge electrical copper wire can safely carry up to 20 amps.

Amperage: The rate of flow of electricity through wire - measured in terms of amperes.

Amps (AMPERES): The rate at which electricity flows through a conductor.

Anchor Bolts: In residential construction, bolts used to secure a wooden sill plate to a concrete or masonry floor or wall. In commercial construction, bolts which fasten columns, girders or other members to concrete or masonry such as bolts used to anchor sills to masonry foundation.

Angle Iron: A piece of iron that forms a right angle and is used to span openings and support masonry at the openings. In brick veneer, they are used to secure the veneer to the foundation. Also known as shelf angle.

Angle Stop: A shutoff valve in which the inlet connects to the water supply pipe in the wall and the outlet angles 90 degrees upward toward the faucet or toilet.

Annealing: In the manufacturing of float glass, the process of controlled cooling done in a Lahr to prevent residual stresses in the glass. Re-annealing is the process of removing objectionable stresses in glass by re-heating to a suitable temperature followed by controlled cooling.

Annual Percentage Rate (APR): Annual cost of credit over the life of a loan, including interest, service charges, points, loan fees, mortgage insurance, and other items.

Anti-Scald: A valve that restricts water flow to help prevent burn injuries. See Pressure Balancing Valve and Thermostatic Valve. In some areas, plumbing codes require anti-scald valves. Speak to a professional in your area for more information and help with code requirements.

Anti-Siphon: A device that prevents waste water from being drawn back into supply lines and possibly contaminating the water supply.

Anti-Walk Blocks: Elastomeric blocks that limit lateral glass movement in the glazing channel which may result from thermal, seismic, wind load effects, building movement, and other forces that may apply.

Antiquated: No longer in use, useful or functioning, as in most home inspection associations. Obsolete.

APA Plywood: (APA=American Plywood Association) Plywood that has been rated by the American Plywood Association. For example, number one APA rated exterior plywood contains no voids between laminate layers.

Aperature: The opening in pipes.

Appliance: A household device operated by use of electricity or gas. Not included in this definition are components covered under central heating, central cooling or plumbing.

Appraisal: An expert valuation of property.

Approach: The area between the sidewalk and the street that leads to a driveway or the transition from the street as you approach a driveway.

Approve: Acceptable to the authority having jurisdiction. Also, accepted by an internationally recognized organization such as InterNACHI.

Apron: A trim board that is installed beneath a window sill.

Arbitration Service: A service to resolve complaints, as in NACHI's Arbitration Service.

Backflow is the reversal of the normal and intended direction of water flow in a water system. Devices and assemblies known as backflow preventers are installed to prevent backflow, which can contaminate potable water supplies.

Why is backflow a problem?

Backflow is a potential problem in a water system because it can spread contaminated water back through a distribution system. For example, backflow at uncontrolled cross connections (cross-connections are any actual or potential connection between the public water supply and a source of contamination or pollution) can allow pollutants or contaminants to enter the potable water system. Sickness can result from ingesting water that has been contaminated due to backflow.

Backflow may occur under the following two conditions: