The City of San Marcos performs free energy audits for its residents. In fact, an audit is required before and after any modification in order to get a city rebate. While this system sounds great, and it is, the problem with it is that the city only has one employee that does this. Needless to say, he is swamped with work. Here it is:
Energy Efficiency Audit Report
6/2/2010
1007 Dale Drive
Prepared By:
Devin Hussey
Conservation Technition
City of San Marcos
630 East Hopkins
San Marcos, TX 78666
dhussey@sanmarcostx.gov
(512)393-8308
1007 Dale is a 1330 square foot single family residence. The homeowner requested an energy audit to learn about and prioritize energy efficiency measures in their home and qualify for energy efficiency rebates. Several opportunities to increase energy efficiency were identified during the energy audit. Many of these energy conservation measures qualify for rebates. HVAC (Heating, Ventilation, and Air Conditioning) Heating and cooling your home uses more energy and drains more energy dollars than any other system in your home. Typically 50‐60% of your electric utility bill goes to heating and cooling your home. The existing HVAC system is composed of the thermostat controls, outside condenser, the inside coiling coil, the furnace, and associated ductwork. The easiest way to save money and conserve energy is to keep the HVAC system’s air filter clean. Check your filter every month, especially during heavy use months (winter and summer). If the filter looks dirty after a month, replace it. At a minimum, change the filter every 3 months. A dirty filter will slow down air flow and make the system use more energy to keep you warm or cool. A clean filter will also prevent dust and dirt from building up in the system which can lead to expensive maintenance and/or system failure. According to the National Association of Home Builders “heating, ventilation, and air conditioning systems require proper and regular maintenance in order to work efficiently, but even in the best case scenarios most components of such systems only last 15 to 25 years. Furnaces on average last 15‐20 years, heat pumps 16 years, and air conditioning units 10‐15 years.” The existing system in your home is a 3 ton system with an outside condenser installed in 2007 mismatched with a gas furnace/cooling coil installed in 1981. Complete replacement of this system qualifies for City of San Marcos rebates. The City of San Marcos rebate program requires at least 500 square feet per ton of cooling capacity unless a Manual J calculation is done.
�� SEER Rating
Manufacturers can make air conditioners and heat pumps operate at different levels of efficiency. The more heat a system can produce or remove from a given amount of electricity, the more efficient it is. A common measurement of this performance is the Seasonal Energy Efficiency Ratio (SEER). SEER numbers can vary widely if you compare air conditioners and old heat pumps to new ones. Twenty year old air conditioners and heat pumps often had peak SEER numbers of 6. The minimum SEER heat pump you can buy today is 10. The new federal standards require all newly manufactured air conditioning systems to be 13 SEER .The highest SEER heat pumps made at present are over SEER 16 and air conditioners are reaching 20 SEER. Any heat pump or air conditioner that has a SEER rating above 14 is very high efficiency.
The SEER numbers are actually a measurement of the efficiency of the heat pump or air conditioner when it is in the cooling or air conditioning mode. Since we live in a warm or hot climate, it makes sense to purchase a system with a high SEER value. People who live in cool or cold climates may not get a payback for the extra money they spend for a high value SEER system. A high SEER heat pump will reduce cooling costs, but may not reduce heating costs. The useful life of most heat pumps is between 14‐16 years. Consider a minimum 14.5 SEER rating to qualify for the rebate program when replacing the unit.
�� ARHI Number
A residential central air conditioner or heat pump has two main parts the condensing unit installed outside of the house and the evaporator installed inside the ductwork. For an air conditioner to work up to specs or to work at all, these two components must be properly matched. Each condenser works properly with only a limited number of evaporator models. Each of the matches has a unique identifier ‐ the ARI reference number. Even if you don't check anything else, you need to verify the ARI reference number before the air conditioner is installed. On the invoice, among other information, you contractor should show three crucial pieces of data ‐ the model number for the condenser, the model number for the evaporator, and the ARI reference number.
�� Manual J
Correct system sizing requires considering many factors other than simply reading the nameplate of the existing unit. Key factors for correctly sizing a heating and cooling system include the following:
• The local climate
• Size, shape, and orientation of the house
• Insulation levels
• Window area, location, and type
• Air infiltration rates
• The number and ages of occupants
• Occupant comfort preferences
• The types and efficiencies of lights and major home appliances (which give off heat).
It is recommended that homeowners should ask that contractors use a correct sizing calculation before signing a contract. This service is often offered at little or no cost to homeowners by major heating equipment manufacturers, and conscientious heating and air conditioning contractors. Manual J, "Residential Load Calculation," published by the Air Conditioning Contractors of America (ACCA), is the recommended method for use in the United States. There are also many user‐friendly computer software packages or worksheets that can simplify the calculation procedure. You should make sure that the procedure used by the contractor follows Manual J. The City of San Marcos rebate program requires at least 500 square feet per ton of cooling capacity unless a Manual J calculation is done. Your home is 1330 square feet; a 2.5 ton system may satisfy your cooling needs while costing less to install and operate.
Duct Sealing
A large opportunity for energy efficiency savings is sealing the air duct system. Average duct leakage in this area is 27%, and your duct system appears to be average. The entire system should be sealed with duct sealing mastic and approved UL (Underwriter Laboratories) labeled foil tape. Rebates are available. See diagrams. Foil tape is convenient for sealing the service access on the HVAC equipment. Use foil tape on the air handler access panel. The return plenums should be sealed. Open filter access panel. Take filter out. Seal any cracks, gaps, or
seams visible within the building cavity return air plenum. Duct leakage must be less than or equal to 12% to qualify for City of San Marcos rebates.
Foil Tape
Seal all joints, seams, and junctions in boots and flexduct connections
Seal all junctions
Seal boots to sheetrock in the attic
Programmable Thermostats
A programmable thermostat helps make it easy for you to save by offering four pre‐programmed settings to regulate your home's temperature in both summer and winter ‐ when you are asleep or away. The pre‐programmed settings that come with programmable thermostats are intended to deliver savings without sacrificing comfort. Depending on your family's schedule, you can see significant savings by sticking with those settings or adjust them as appropriate for your family. The key is to establish a program that automatically reduces heating and cooling in your home when you don't need as much. A $50 rebate is available to install a programmable thermostat.
Insulation
Insulation is one of the keys to a comfortable, energy‐efficient home. With inadequate insulation a home can have excessive heat gain during the summer and heat loss in the winter—forcing the heating and cooling systems to work overtime. Insulation is rated by R‐valve (resistance to heat flow); the greater the R‐value the better the insulation. Attic insulation should be R‐30 to R‐60 in this climate zone according to the U.S. Department of Energy. Your attic has R‐19 fiberglass insulation on the attic floor. Consider adding additional R‐19 (6 to 7 inches) insulation to achieve R‐38 and qualify for San Marcos rebates.
Reflective Insulation/Radiant Barrier
Radiant barriers are more effective in hot climates than in cool climates, especially when cooling air ducts are located in the attic. Some studies show that radiant barriers can lower attic temperature up to 20 degrees and reduce cooling costs between 15% and 20% when used in a warm, sunny climate. The barriers consist of a highly reflective material that reflects radiant heat rather than absorbing it. To perform properly, radiant barriers need to face open space through which there would be radiation. This house would benefit from a radiant barrier and receive rebates for installing one.
Air Infiltration
Reducing air infiltration and air leakage can improve the energy efficiency, air quality, and comfort of your home. Tightening up home construction can offer you:
• Improved comfort — reduces drafts, noise, and moisture.
• Improved indoor air quality — keeps dust, pollen, car exhaust, and insects out of the home.
• Lower costs — reduces escape of conditioned air.
Unfortunately, there are hundreds of penetrations through a typical home's exterior. These gaps and holes are often incurred during framing, and from penetrations for wiring, plumbing, and ducts. Reduced air infiltration combined with proper ventilation can reduce your energy bills and it can also improve the quality of your indoor air. Outdoor air that leaks indoor makes it difficult to maintain comfort and energy efficiency. In addition, air leakage accounts for 25–40% of the energy used for heating and cooling in a typical home. To reduce air infiltration and air leakage:
• Seal all plumbing penetrations inside under sinks and behind toilets
• Seal the attic floor. The attic floor should be a continuous air barrier. Seal any gaps or cracks,
wires, ducts, or pipes where they penetrate the attic floor with caulk or expanding foam.
• Replace exterior siding where rotting.
• Consider air tight access panels instead of the vents for behind the bathtubs.
Appliances
Appliances account for about 17% of your household’s energy consumption, with refrigerators, clothes washers, and clothes dryers at the top of the consumption list. The CEE (Consortium for Energy Efficiency) rates refrigerators, dishwashers, and clothes washers that are more efficient within the ENERGY STAR rating system. Performance levels are established at 20% (tier I, 25% (tier II) and 30% (tier III) more efficient than federal minimum standards. Rebate amounts vary according to CEE tier levels. Consult the energy efficient appliance info sheet at
http://sanmarcostx.gov/gogreen for more detail.
�� Refrigerators
New refrigerators are much more energy‐efficient than their 10‐20‐year‐old ancestors. In fact, new units often consume less than half the energy of comparable old units. Most new units will use less than 1,000 kWh per year compared to the 1,500‐2,500 kWh per year for the older units. This drop is large enough so that many people actually notice a drop in their utility bills (as much as $15 per month) after the new one arrives. Look for the ENERGY STAR label when buying a new refrigerator. ENERGY STAR models are at least 20% more efficient than the federal minimum standard. Select a new refrigerator that is the right size for your household. Top freezer models are more energy efficient than side‐by‐side models. Features like icemakers and water dispensers, while convenient, will increase energy use.
�� Dishwashers
Studies are showing more and more that, when used to maximize energy‐saving features, modern dishwashers can outperform all but the most frugal hand washers. About 60% of the energy used by a dishwasher goes towards heating the water, so models that use less water also use less energy. Thanks to national efficiency standards, new models use less than half the water that old models used (made before 1994). With these advances come new standards for dishwashers, effective 2009, that will restrict energy and water use even more.
�� Water Heaters
The gas condensing unit you installed is one of the most efficient water heaters available. Congratulations on your good choice.
Windows
The U.S. Department of Energy and the Environmental Protection Agency has reported that a home withexterior window shading will require less energy to keep it cool lowering utility expenses in your home. Window films, solar screens, external shutters, and deciduous trees are among the most effective methods for shading windows. Interior curtains or drapes can help, but it is best to prevent the summer heat from getting past the glass and inside. Exterior shading on all of the windows that receive at least one hour of direct sunlight would decrease the air conditioning electric consumption.
Lighting
Consider replacement of light bulbs. LED (light emitting diode) lamps are available to fit standard sockets found in homes and only consume one to two watts of power and last up to 25 times longer than standard incandescent bulbs. CFL (compact fluorescent) lamps are also available which consume approximately seven watts and last up 10 times longer than standard bulbs. These high efficiency options are comparable to the standard 40 to 100 watt incandescent bulbs usually found in residential homes.
Electronics
Computers should be turned off or set to hibernate when not in use. The computer peripherals
(printers, speakers, modems, etc.) should be plugged into power strips and the power strips should be turned off when not in use. Most electronic equipment including televisions, VCRs, DVDs, and stereo systems take a continual draw of electricity to remain in standby mode. Phone chargers and laptop cords also continually draw power when they are plugged in even when the phone or laptop is disconnected from the cord. This electricity consumption when electronics are turned off but still plugged in is called “phantom load” and consumes vast amounts of electricity year round. The easiest way to avoid phantom load is to plug everything into power strips and be sure the power strips are turned off when not in use.
Rebates and Incentives
Recommendations for your home which qualify for the San Marcos rebate programs:
• HVAC replacement
• Duct sealing
• Programmable thermostat
• Attic insulation
• Radiant barrier
• Water Heater replacement
• Refrigerator replacement
• Clothes Washer replacement
http://sanmarcostx.gov/gogreen
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