What is a Home Energy Audit?
What is a Home Energy Audit?
A home energy audit is a service where the energy efficiency of a house is evaluated by a person often using professional equipment such as a blower door and infrared cameras, with the aim to suggest the best ways to improve energy efficiency in heating and cooling the house. The energy auditor should do an examination of the entire residence inside and out, as well as a review of past utility bills. They may use equipment to detect sources of energy loss, such as blower doors, infrared cameras, furnace efficiency meters, combustion analyzer and surface thermometers.
Preparing for an Energy Assessment
Before the energy auditor visits your house, make a list of any existing problems such as moisture, mold and uncomfortable or drafty rooms. Have copies or a summary of the home's yearly energy bills. You can go online to BlueRidgeEMC.com to pull a 12-month history, or call Blue Ridge directly to get sent to you. Auditors use this information to establish what to look for during the audit. The auditor first examines the outside of the home to determine the size of the house and its features. The auditor then will analyze the resident’s behavior:
- Is anyone home during working hours?
- What is the average thermostat setting for summer and winter?
- How many people live here?
- Is every room in use?
Selecting an Home Energy Auditor
Blue Ridge Electric has established a list of local auditors for you to choose from. Most auditors will offer two levels of audits with different price ranges related to the size of your home.
Typically, there are two levels of audits available: a Home Energy Survey and a Building Performance Audit. A Home Energy Survey is a visual inspection and does not include the use of diagnostic testing equipment. Its purpose is to assess the general energy performance of and existing home. The Home Diagnostic Audit includes all the inspections provided in the Home Energy Survey and also includes diagnostic testing using specialized equipment such as a blower door, duct leakage tester, combustion analyzer and infrared camera.
A level I Home Energy Survey often ranges from $150-300. The level II Building Performance Audits generally starts around $300 and may exceed $500 depending on the size of the residence and the complexity of the heating and cooling system.
Prices and services may vary between auditors, so do some research to find the one that is right for you.
Blower Door Tests
Professional energy auditors use blower door tests to help determine a home's air tightness. These are some reasons for establishing the proper building tightness:
- Reducing energy consumption due to air leakage
- Avoiding moisture condensation problems
- Avoiding uncomfortable drafts caused by cold air leaking in from the outdoors
- Making sure that the home's air quality is not too contaminated by indoor air pollution
Preparing for a Blower Door Test
Take the following steps to prepare your home for a blower door test:
- Close windows and open interior doors
- Turn down the thermostats on heaters and water heaters
- Cover ashes in wood stoves and fireplaces with damp newspapers
- Shut fireplace dampers, fireplace doors, and wood stove air intakes.
Energy auditors may use thermography—or infrared scanning—to detect thermal defects and air leakage in building envelopes.
Preparing for a Thermographic InspectionTo prepare for an interior thermal scan, the homeowner should move furniture away from exterior walls and remove drapes. The most accurate thermographic images usually occur when there is a large temperature difference at least 20°F between inside and outside air temperatures.
Duct Blaster Testing
A duct leakage performance test involves pressurizing the duct system with a calibrated fan and simultaneously measuring the air flow through the fan and its effect on the pressure within the duct system. The tighter the duct system, the less air you need from the fan to create a change in duct system pressure. Testing procedures can be set up to measure only duct leaks which are connected to the outside, or to measure total duct leakage (i.e. leaks connected to the outside and inside of the house). Duct leakage measurements are used to diagnose and demonstrate leakage problems, estimate efficiency losses from duct leakage, and certify the quality of duct system installation.
Comprehensive HERS Rating
A Comprehensive Home Energy Rating System (HERS) is the most in-depth performance audit of an existing home. It consists of the evaluation, diagnostic testing, cost-effective recommendations and work specifications contained in a Building Performance Audit.
In addition, a Comprehensive HERS Rating includes a computerized simulation analysis utilizing accredited rating software to calculate a rating score on the HERS Index. The report will also contain a cost/benefit analysis for the recommended improvements and expected return on investment. Comprehensive HERS Ratings of existing homes will be required to qualify loan applicants for certain federally sponsored mortgage products. Most HERS Ratings are done on new homes that are under construction and seeking the rating to help sell the home.
