D'Uva Energy Audit Case Study Final Draft WithChart

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• Publié par: Opsue
• Nombre de lectures: 94
• Langue: English

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AIRE Energy Audit Case Study #1

Going to Town for Energy Savings SITUATION Andrew D’Uva wanted to make a difference with his home. A North Arlington resident in an 18year old townhouse, he wanted to save money and help the environment with a new energyefficient approach to home maintenance. The townhouse had the advantage of sidebyside insulation from neighboring units, but aging systems and air leaks led to high bills and wasted energy. For instance, the front door of his fourstory unit seemed leaky, and the top floor was never quite comfortable— either too cold or too warm depending on the season. He felt a home energy audit would identify other potential areas for improvement. Earlier this year, Andrew applied for a Countysponsored energy audit through the Arlington Fresh AIRE program and was one of a handful of lucky townhouse residents to be selected at random to participate. THE AUDIT In April 2007, Andrew’s townhouse was the site of a threehour audit that included an occupant interview, a visual inspection, and air leakage testing. The interview assessed Andrew’s comfort level and typical living patterns in the home, the number of occupants and other noticeable problems. Additionally, Andrew informed the audit team just how much he could invest in future improvements.

An infrared camera helped capture temperature changes from leaks around windows, behind walls, where they are invisible, and at the front door where Andrew had noticed leakage problems.

Following the interview, the energy auditor set up a blower door test, a giant fan that pulls air outward through a door opening to measure natural air leakage.Then, the auditor conducted a walkthrough inspection of the home to examine windows, doors, heating and cooling equipmentand potential poor construction practices. Using an infrared camera, the audit team noticed temperature changes due to leaks around windows, behind walls, and at the front door all of which were more pronounced with the air drawn through the house by the blower door fan. The EMO Energy Solutions audit team found that Andrew’s whole house infiltration rate was .80 air exchanges per hour (ACH), which is typical for singlefamily detached homes, but a little high for a townhouse. The hourly air exchange rate for an energyefficient home is about .32. FINDINGS AND OPPORTUNITIES The audit team found many opportunities for improvement. As Andrew had suspected, the front door was leaking air, and the fourth floor had extensive infiltration problems. Air was leaking through the master bedroom eaves and other penetrations such as the attic kneewalls and a warped window. The beautiful cathedral ceilings adjoining the roof left the top floor exposed to outdoor temperature extremes. Other problem areas included electric outlets, poor air circulation to a first floor bathroom, and an open fireplace damper. Save for the master bedroom window, the 18year old doublepane windows in the rest of the house were in good condition. But Andrew’s 18year old HVAC system was nearing the end of its useful lifespan. Replacing the townhouse’s natural gas furnace and 2.5 ton electric air conditioner with more efficient equipment could make a big difference.

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AIRE Energy Audit Case Study #1

 EMOprovided a report  thatincluded an  energycost analysis of  thepast year. The final audit report recommended the following strategic improvements to make his home more comfortable and energyefficient: ‰Seal the knee wall of the eaves in the top floor bedroom and access doors. ‰Insulate these surfaces with either batt or foam to at least R13. ‰Shore up unwanted air leaks, seal outlets and light switchesespecially in the kitchen. ‰Repair or replace the warped window in the master bedroom. ‰Seal the leaky front door with a door sweep. ‰Provide additional conditioning with a dedicated thermostat for the townhouse top floor. ‰Keep air flowing between the first floor bathroom and the rest of the house by keeping doors open or installing a grate. ‰Close the fireplace damper. ‰Turn off the pilot when the gas fireplace is not in use. Other basic recommendations included replacement of incandescent lights with CFLs, which could save as much as 80 percent on lighting electricity; turning off lights in unoccupied rooms; and switching to ® ENERGY STARappliances when new ones are needed. RESULTS Andrew D’Uva chose to follow up on many of the audit recommendations, including: 9Sealing the electric outlets with templates 9Insulating and air sealing on the fourth floor. 9Replacing the outdated furnace and AC system with an 80percent efficient heat pump/furnace system. 9Replacing most lighting with CFLs Andrew decided against a separate conditioning system for the fourth floor due to cost, but decided to replace the outdated furnace and AC unit. According to Andrew, “Natural gas prices seem to be climbing. Electricity in Virginia is relatively less expensive to achieve the same heating/cooling effect. This creates an opportunity to benefit in winter by using a heat pump in conjunction with a gas furnace. I expect to save $500 a year with this system.”Also, Andrew will be eligible for a $300 federal tax credit on his new energyefficient equipment.

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