HOME PERFORMANCE ENERGY ANALYSIS

Transcription

1 Certifed Home, Termite, Green & Commercial Inspectors HOME PERFORMANCE ENERGY ANALYSIS ON 1234 ANY STREET; PHOENIX, AZ PREPARED FOR: JOHN DOE JANUARY 23, 2009 BY: PAUL A. FURMAN, P.E., LEED-AP Hire the Best and Expect Nothing Less AJF Engineering, Inc E. Acoma Drive #203 Scottsdale, AZ Tel: Fax:

2 Section 1: Introduction Thank you for the opportunity to complete an energy performance analysis of your home. The client expressed concern about the high electric bills, despite the recent installation of double pane windows, new water heater, additional attic insulation and 14 SEER (Seasonal Energy Efficiency Rating) air conditioning system. The home was built in 1981 and is approximately 1050 sq. ft. The primary systems and factors that affect energy efficiency and utility cost are: 1. air leakage through the home s walls and ceilings. 2. windows and doors 3. wall and ceiling insulation 4. heating and cooling efficiency and duct leakage 5. domestic water heating 6. lighting Each of these systems and components are evaluated and documented in the sections that follow. Each section describes what was evaluated, what we found and recommendations to increase the energy efficiency of the home. Photographs and infrared images are located at the end of the report. The photos support the issues identified in the report. Some energy saving tips are offered below: Monitor the refrigerator and freezer temperatures and keep the refrigerator between 38 and 42 degrees and the freezer between 0 and 5 degrees. Periodically vacuum/clean refrigerator coils Set your cooling thermostat to 78 degrees or higher and increase the temperature 2-3 degrees when you are not home. Use ceiling fans to allow setting the thermostat to a higher temperature. Turn off lights, televisions, computers and other electric users when not in use. Do laundry after 9:00 pm when electric rates are lower. Use a cooking timer to reduce shower duration. 2 Home Energy Analysis

3 Section 2: Outside Air Leakage The thermal envelope of your home is a barrier to the outside weather and consists of the exterior walls and attic floor. If your home is well insulated, with limited air-leakage, the temperature inside is more efficiently controlled. Air leakage into the home is required to provide fresh air for breathing and to remove indoor air pollutants. Excess air leakage has an adverse affect on indoor comfort and energy costs. Important Concept: Air leaking into your home constantly replaces air that is leaking out. Thus, if you stop air leaking out, you will prevent air from leaking in. Your comfort will depend on how well you control outside air-leakage with a continuous air-barrier, (stop the air-leak arrows shown), around the living space in your home. We conducted a blower door test to measure the air leakage into the home. The test uses a calibrated fan to exhaust air out of the home. As air leaves the home through the fan, it is replaced with air from the outside through openings in the building envelop. The blower door test allows us to measure the air leakage and calculate a natural air leakage rate. We also scanned the interior ceilings and walls with an infrared (IR) camera to identify the sources of leakage. The IR camera can measure the surface temperature of the walls and ceilings to identify hot spots due to leakage of hot outside air into the home. What We Found The blower door test calculated that your home has a natural air leakage rate of 62 cubic feet per minute (CFM). This means that 62 cubic feet of air volume inside your home is exchanged with the outside every minute. The American Society of Heating, Refrigeration, and Air Conditioning Engineers (ASHRAE) sets minimum ventilation rates to ensure acceptable air quality in homes. ASHRAE suggests a minimum ventilation rate of 15 CFM for each occupant. Based on two occupants (yourself and your cats!), you could reduce your air infiltration rate to 2x15 = 30 CFM and still provide adequate ventilation. Therefore, your home s air leakage is approximately double the required ventilation rate. Significant savings can be obtained by reducing the air infiltration rate without adversely affecting the indoor air quality. 3 Home Energy Analysis

4 Recommendations The sources of air leakage that can be corrected from easiest to hardest are identified below (photos follow the recommendations): Wall switches and outlets are not sealed. Seal penetrations in the ceiling that have direct communication with the attic air (recessed lights, fan junction boxes, etc,). Seal the attic access opening Seal the weep screed at the bottom of the exterior stucco wall. The weep screed has gaps/openings that provide a direct path into the exterior wall cavity. Seal exterior window frames. Seal the bay window in the family room. Seal plumbing and wire penetrations in wall top plates located in the attic. 4 Home Energy Analysis

5 Section 3: Windows and Doors Windows are a significant contributor to the overall heating and cooling costs. Windows have low R values when compared to the walls vary from R1 to R4. For Arizona, the most important factor for windows is their ability to reduce the solar heat gain through the window. Double pane, low E windows can reduce the solar heat gain by up to 65% - that is 65% of the solar heat does not enter the home. This compares to non low E windows which reduce the solar heat gain by approximately 20%. Interior and exterior shading can significantly reduce the solar heat gain to the home, regardless of whether low E or non-low E windows are installed. What We Found All windows are recently installed double pane, low E windows. The doors have also been recently replaced with high quality, energy efficient doors. Recommendations The front door and weather stripping requires minor adjustment or replacement to reduce air infiltration. 5 Home Energy Analysis

6 Section 4: Wall and Attic Insulation Wall and attic insulation impedes the flow of heat into or out of the home. Typical materials used for insulation are fiberglass and cellulose. The insulation levels are defined by the R-value. The higher the R-value the more resistance to heat flow the insulation provides. The recommended minimum insulation levels are R38 at the attic and R11 at the walls. What We Found Wall Insulation: The exterior walls are wood framed and typically insulated with fiberglass batt insulation. The insulation is covered by finished materials (sheetrock and stucco) and is not visible for inspection. However, we used an infrared camera to determine the performance of the wall insulation. For the most part the wall insulation is performing to standards except for a few areas. Since these areas are not accessible, we do not recommend correcting these deficiencies. Attic Floor Insulation: Blown cellulose insulation is used to insulate the attic floor. The thickness varies from location to location, but appears to have an approximately R value of 30. However, a considerable amount of air-leakage does exist in your attic at areas such as, around plumbing chases, can-lights, top wall plates, open chase ways, wire chases, etc. (see section 2). This air leakage significantly reduces the effective R-value of the insulation. Attic Kneewall Insulation The attic kneewall(s) are walls that separate the attic from the conditioned space of the home. They are insulated with fiberglass batt insulation. The kneewall fiberglass insulation is missing and misplaced which reduces the effective R-value to essentially zero at the kneewall. Recommendations: Walls: No action. Ceiling: Add insulation to achieve an R value of 38. Kneewall: Add insulation to achieve an effective R value of 38. Another option to correct the attic insulation deficiencies and also reduce the air infiltration into the home is to insulate the underside of the attic rafters with icynene foam. 6 Home Energy Analysis

7 Icynene foam applied to the underside of the rafters. Insulating the underside of the attic rafters with icynene foam effectively converts the attic space to a conditioned space. The advantages are: No longer do you have air infiltration between the unconditioned attic and home due to recessed lighting fixtures, fan junction boxes, openings in the wall top plates, etc. (refer to Section 2) The air conditioning ducts are located in a conditioned attic which means they do not have to be insulated or sealed (refer to Section 6). The existing attic floor and kneewall insulation can be left in place and do not have to be upgraded. For additional information about icynene insulation please refer to 7 Home Energy Analysis

8 Section 5: Cooling and Heating Systems The efficiency of the cooling system, and to a lesser extent the efficiency of the heating system, has a significant impact on your utility bills. Current standards require air conditioners to achieve a minimum Seasonal Energy Efficiency Ratio (SEER) of 13. Manufacturers offer cooling systems up to 20 SEER, although at a significantly higher cost than 13 SEER. Heating and cooling systems should be serviced twice a year, filters should be replaced as required and the exterior condenser coil should be periodically cleaned to achieve maximum efficiency and performance. What We Found: The heat pump (which provides both cooling & heating) is 5 years old with a SEER rating of 14. Recommendations No action. The installed cooling and heating systems meet minimum efficiency standards. The air conditioning condenser and evaporative coils should be periodically cleaned, filters changed regularly and the air conditioning system serviced regularly to maintain nameplate efficiency. 8 Home Energy Analysis

9 Section 6: Heating and Cooling Ducts Ducts that are not sealed have a significant impact on the utility bills. In Arizona, supply and return ducts are typically located in an unconditioned area, such as an attic. Leaks in the supply ducts result in cool air never making it to the home and leaks at the return ducts draw unconditioned air into the home that must then be cooled (or heated). In addition, the air pressure in the home can be negatively influenced by duct leakage (either pressurized or depressurized) which results in greater air leakage through openings in the building envelop identified in Section 2. Ducts located in an unconditioned area (i.e., attic) should also be insulated to reduce the cooling loss to the unconditioned area through the duct walls. What We Found: Round sheet metal ducts are installed in the attic with fiberglass insulation wrapped around the ducts to provide an R value of approximately 2-3. The insulation did not allow us to inspect the ducts. However, sheet metal ducts installed in the early 1980s are typically not sealed at the joints/connections and have significant air leakage. Recommendations: Remove the existing fiberglass insulation, seal the duct joints and connections and install new insulation with an effective R-value of 8 to meet current energy standards. As an alternative, the attic can be converted to conditioned space by insulating the attic rafters and the existing ducts can be left as-is (see section 4). 9 Home Energy Analysis

10 Section 7: Domestic Water Heating Providing hot water from a water heater with a storage tank typically consumes about 15% to 20% of total household energy, and the typical water heater lasts about years. However, this is largely dependent upon how many occupants use water, how many dishes and clothes are washed, water quality, water temperature, and how the unit is maintained. Typical household hot water use based upon national averages. What We Found: A 4 year old, 50 gallon electric water heater is installed. An electric storage water heater has an efficiency of approximately 60% - which means approximately 40% of the energy is wasted. Unfortunately, high efficiency (90%) or better water heaters are not easily available and are cost prohibitive. Recommendations Retain the existing water heater and implement hot water conservation strategy to reduce the required hot water demand: Wash with cold water only. Upgrade to low volume shower fixtures Replace appliances with Energy Star appliances Installing a solar water heating system is also an option. The initial installation cost can be significantly reduced by utility, local government and federal government rebates. Depending on your water use, the pay back period can be 2 to 4 years for a solar water heater. For additional information, please refer to and 10 Home Energy Analysis

11 Section 8: Lighting Compact Fluorescent Light bulbs (CFL) offer a significant cost savings over traditional incandescent light bulbs. CFLs use up to 80% less electricity and last up to 10 times longer. They produce significantly less heat which results in a lower demand on the cooling system. We highly recommend CFLs for all your lighting fixtures. 11 Home Energy Analysis

12 Section 9: Photos and Infrared Images These photos show items of interest relative to the analysis findings. Infrared images show temperature in color ranging from cold temperatures in BLUE and hotter temperatures in RED. The blue temperatures show areas of air infiltration or inadequate/ineffective insulation. Seal underside of the family room bay window. Seal weep screed at the bottom of the stucco wall. Seal window frame. Seal door threshold 12 Home Energy Analysis

13 Insulation thickness varies and should be redistributed. Batt fiberglass insulation missing at the attic kneewall. Insulation thickness varies and should be redistributed. Infrared Photos: Non-performing or missing insulation at the attic floor. 13 Home Energy Analysis

14 Non-performing or missing insulation at the attic floor and around the tube skylight. Air leakage at wall/floor joint. Non-performing or missing insulation at the exterior wall and air leakage at the wall top plate. 14 Home Energy Analysis

15 Non-performing or missing insulation at the exterior wall/attic and air leakage at the wall top plate. Missing and non-performing insulation at the attic knee wall. Missing and non-performing insulation at the attic knee wall. Missing and non-performing insulation at the attic knee wall. Missing and non-performing insulation at the attic floor and air infiltration at the ceiling penetrations. 15 Home Energy Analysis

16 Air infiltration and missing insulation at the light fixture junction box. More non-performing/missing insulation and air infiltration at the exterior wall/ceiling. More air infiltration and missing insulation at the light fixture junction box. Air leakage at the heating system duct in the attic (red image). 16 Home Energy Analysis