Recent federal tax incentives are designed to persuade people to make their homes more energy efficient, and could spur a small boom in conservation–minded projects. But if you're one of the ones suddenly galvanized into the green movement, take a breath. Consider hiring an energy auditor first. It's great to want to save resources, and even better if the government wants to give you a tax break on purchases of energy-efficient windows, a new boiler, or even solar panels. But would you take $10,000 and invest it in a single stock without at least reading your paper's business section? Of course not, yet people every day look at their windows, for instance, and decide they need replacing at a cost that can easily climb past $10,000.

Having some money sense, you want to at least talk to a credible auditor or two (more on how to determine credibility later). For about $400, depending on the size of your home and the complexity of the project, a rater will analyze your home and recommend solutions. The windows you worried about might pale in energy waste compared to vents or insulation holes. Raters use infrared cameras, large fans, and electronics to pinpoint leaks. The resulting report details problems, and suggests prioritized remedial steps. It also estimates how much the work should cost you and what the return on your investment is likely to be. Before you sign a contract, make sure you have the firm that's right for you. No matter where you get a name, be aware that some auditors work for companies selling the goods the auditors recommend. When you meet auditors, make sure you understand the difference between an auditor and rater, ask them for references, for industry associations they belong to, and for training certificates. 

BHES Professional Energy Rating

Professional energy ratings generally go into great detail. BHES will do a room-by-room examination of the residence, as well as a thorough examination of past utility bills.

BHES energy ratings will include a blower door test and will also include a thermographic scan. There's also another type of test—the PFT air infiltration measurement technique—but it is rarely offered.

Preparing for an Energy Rating

Before BHES visits your location, make a list of any existing problems such as condensation and uncomfortable or drafty rooms. Have copies or a summary of the building's yearly energy bills. (Your utility can get these for you.) Raters use this information to establish what to look for during the rating. The rater first examines the outside of the building to determine the size of the building and its features (i.e., wall area, number and size of windows). The rater then will analyze the residents' behavior:

• Is anyone occupying the building during working hours?
• What is the average thermostat setting for summer and winter?
• How many people use the building?
• Is every room in use?

Your answers may help uncover some simple ways to reduce your building's energy consumption. Walk through your structure with the raters as they work, and ask questions. They may use equipment to detect sources of energy loss, such as blower doors, infrared cameras, furnace efficiency meters, and surface thermometers.

Selecting Your Energy Rater

There are few places where you can locate professional energy rating services in the Black Hills. Your state or local government energy or weatherization office may help you identify a local company or organization that performs audits. They may also have information on how to do your own audit. Your electric or gas utility may conduct residential energy audits or recommend local raters. Also check your telephone directory under headings beginning with the word "Energy" for companies that perform residential energy ratings.

Be aware that there is a major difference between and Energy Audit and an Energy Rating. An energy audit is only a consultation or recommendations on energy conservation tips and techniques.  An energy rating is setting up specialized equipment described in the following paragraphs.  A rating involves a process to measure energy waste. Be careful not to misinterpret the difference between a Rating and an Audit.

Before contracting with an energy rating company, you should take the following steps:

• Get several references, and contact them all. Ask if they were satisfied with the work.
• Call the Better Business Bureau and ask about any complaints against the company.
• Make sure the energy auditor uses a calibrated blower door.
• Make sure they do thermographic inspections or contract another company to conduct one.

                                                

A blower door is a diagnostic tool designed to measure the airtightness of buildings and to help locate air leakage sites. A blower door consists of a calibrated fan for measuring an air flow rate and a pressure sensing device to measure the pressure created by the fan flow. The combination of pressure and fan flow measurements are used to determine the building airtightness. The airtightness of a building is useful knowledge when trying to increase energy conservation or decrease indoor air pollution or control building pressures.

Blower doors can be used in a variety of types of testing. These include (but aren't limited to):

• NFPA Clean Agent Retention testing (this type of testing is usually described as a door fan test rather than a blower door test)
• Testing residential houses for air tightness
• Testing buildings for compliance with standards for energy efficiency, such as those by the Leadership in Energy and Environmental Design (LEED) and Passive House/Passivhaus.
• Testing building envelopes and window frames for water tightness and rain penetration

                                   

Thermography measures surface temperatures by using infrared video and still cameras. These tools see light that is in the heat spectrum. Images on the video or film record the temperature variations of the building's skin, ranging from white for warm regions to black for cooler areas. The resulting images help the rater determine whether insulation is needed. They also serve as a quality control tool, to ensure that insulation has been installed correctly.

A thermographic inspection is either an interior or exterior survey. The energy rater decides which method would give the best results under certain weather conditions. Interior scans are more common, because warm air escaping from a building does not always move through the walls in a straight line. Heat loss detected in one area of the outside wall might originate at some other location on the inside of the wall. Also, it is harder to detect temperature differences on the outside surface of the building during windy weather. Because of this difficulty, interior surveys are generally more accurate because they benefit from reduced air movement.

Thermographic scans are also commonly used with a running blower door. The blower door helps exaggerate air leaking through defects in the building shell. Such air leaks appear as black streaks in the infrared camera's viewfinder.

Thermography uses specially designed infrared video or still cameras to make images (called thermograms) that show surface heat variations. This technology has a number of applications. Thermograms of electrical systems can detect abnormally hot electrical connections or components. Thermograms of mechanical systems can detect the heat created by excessive friction. Energy raters use thermography as a tool to help detect heat losses and air leakage in building envelopes.

Infrared scanning allows energy raters to check the effectiveness of insulation in a building's construction. The resulting thermograms help raters determine whether a building needs insulation and where in the building it should go. Because wet insulation conducts heat faster than dry insulation, thermographic scans of roofs can often detect roof leaks.

In addition to using thermography during an energy rating, you should have a scan done before purchasing a house; even new houses can have defects in their thermal envelopes. You may wish to include a clause in the contract requiring a thermographic scan of the house. A thermographic scan performed by a certified technician is usually accurate enough to use as documentation in court proceedings.

The energy rater may use one of several types of infrared sensing devices in an on-site inspection. A spot radiometer (also called a point radiometer) is the simplest. It measures radiation one spot at a time, with a simple meter reading showing the temperature of a given spot. The rater pans the area with the device and notes the differences in temperature. A thermal line scanner shows radiant temperature viewed along a line. The thermogram shows the line scan superimposed over a picture of the panned area. This process shows temperature variations along the line. The most accurate thermographic inspection device is a thermal imaging camera, which produces a 2-dimensional thermal picture of an area showing heat leakage. Spot radiometers and thermal line scanners do not provide the necessary detail for a complete home energy rating. Infrared film used in a conventional camera is not sensitive enough to detect heat loss.

Preparing for a Thermographic Inspection

To prepare for an interior thermal scan, the homeowner should take steps to ensure an accurate result. This may include moving furniture away from exterior walls and removing drapes. The most accurate thermographic images usually occur when there is a large temperature difference (at least 20°F [14°C]) between inside and outside air temperatures. In northern states, thermographic scans are generally done in the winter. In southern states, however, scans are usually conducted during warm weather with the air conditioner on.