Home Energy Assessments (Energy Audits)
Why have an Energy Assessment?
There are several reasons to have an energy assessment performed on your home. You may have just received your utility bill and what to figure out how to decrease the amount. There may be comfort issues or health and safety issues. Or you maybe you just want to minimize your impact to the world we live in.
What is an Onsite Energy Assessment?
An energy assessment of a home may involve recording various characteristics of the building envelope including the walls, ceilings, floors, doors, windows, and skylights. For each of these components the area and resistance to heat flow (R-value) is measured or estimated. The leakage rate or infiltration of air through the building envelope is of concern, both of which are strongly affected by window construction and quality of door seals such as weatherstripping. The goal of this exercise is to quantify the building's overall thermal performance. The audit may also assess the efficiency, physical condition, and programming of mechanical systems such as the heating, ventilation, air conditioning equipment, and thermostat. A home energy assessment may also include a written report estimating energy use given local climate criteria, thermostat settings, roof overhang, and solar orientation. This could show energy use for a given time period, say a year, and the impact of any suggested improvements per year. The accuracy of energy estimates are greatly improved when the homeowner's billing history is available showing the quantities of electricity, natural gas, fuel oil, or other energy sources consumed over a one or two-year period. Some of the greatest effects on energy use are user behavior, climate, and age of the home. An energy audit may therefore include an interview of the homeowners to understand their patterns of use over time. The energy billing history from the local utility company can be calibrated using heating degree day and cooling degree day data obtained from recent, local weather data in combination with the thermal energy model of the building. Advances in computer-based thermal modeling can take into account many variables affecting energy use. A home energy assessment is often used to identify cost effective ways to improve the comfort and safety of buildings. In addition, homes may qualify for energy efficiency grants from local and central government.
The Four Steps of a Energy Assessment:
Step 1 INSPECTION
A certified energy inspector examines and measures the home for ways to improve indoor air quality, improve the comfort of the home and all opportunities for energy savings.
Step 2 BLOWER DOOR
The inspector will set up a blower door that will simulate a 20 mph wind from the exterior. The inspector will identify and document areas of leakage.
Step 3 DETAILED ANALYSIS
Specialized software produces a Report which shows savings and costs for energy efficiency improvements and provides tips on ways to save more energy and reduce your energy bills.
Step 4 IMPLEMENTATION
MANY OF THE REPAIRS CAN BE ACCOMPLISHED BY YOU, however if you are not comfortable with a repair, the Report provides access to a database of contractors and access to other energy products and services.
Sample Mini Energy Survey (Asset Energy Inspection)
A true energy assessement consists of three (3) inspections. First is the test-in, second is the intermediate and third is the test-out.
Home Performance Assessment or “Test-in.” A certified energy specialist trained in building science principles (i.e. BPI Energy Auditor or equivalent is acceptable) will perform a Home Performance Assessment (HPA) which will include a visual and diagnostic energy inspection of the home using a form standardized for the program.
Inspection Results and Recommended Improvements. Improvements to the home will be recommended based on the initial inspection and homeowner interview. The homeowner will be given a review of the findings and provided with a summary report including:
A summary of HPA findings
An estimation of costs for the improvements
NOTE: Recommendations for improvements will be on a fuel-neutral basis.
Installation of measures. The program will help homeowners identify qualified contractors able to implement the HPA recommendations. This can either be the participating contractor providing the inspection and recommendations or other contractors qualified in home energy inspection, building science, and proper installation techniques. All installed measures will be in accordance with industry best practices.
Post-Installation Tests or “Test-out.” A certified energy specialist trained in building science principles (i.e. BPI Energy Auditor or equivalent is acceptable) will verify and document the performance of installed measures and verify that health and safety standards are met (test-out). A summary of the improvement and final test results will be given to the homeowner. The results may be in the form of a “Summary Certificate.
All electric home:
Home with gas service: