Q. A home energy audit is usually the best first step before embarking on a remodel. Tell us what your team looks for when conducting one and what types of special tools and technologies you use to pinpoint problem areas.
A. The quality and sophistication of energy auditing tools has increased dramatically in the past decade. These days, a typical energy auditor will show up for an evaluation with somewhere between $30K to $50K worth of inspection tools! Popular gadgets include blower door units, duct blasters, infrared cameras, gas leak detectors, combustion analyzers, dry/wet bulb thermometers, tools for airflow measurement, monometers (pressure gauges), gauges to check a/c refrigerant charge, and so on.
Even the most basic audit should include a scan of the interior of the house with an infrared camera. Infrared cameras allow inspectors to see "behind" walls to detect missing or improperly installed insulation. They also help identify air leakage to some extent.
A step up from an infrared scan is an audit that combines this tool with a blower door. A blower door is literally a temporary door with big fan in it, usually installed in the main entry of a home. They are used to blow air out of a home in order to quantify the amount of infiltration, or air leakage, under natural conditions. As air is blown out with the blower door, ambient outdoor air gets sucked in through all of the cracks and gaps in the floor, walls, and ceiling - where it normally leaks. On moderately cold or hot days, a blower door can be used with an infrared camera to pinpoint the exact location of air leaks because the ambient air will show up as a different color on the camera's digital screen as it is pulled into the house. Identifying and fixing infiltration is very important because 25% to 50% excess energy use in a home can be due to air leakage.
More sophisticated audits include detailed diagnostic testing of heating and air conditioning systems. Heating and cooling systems are almost always the largest users of energy in a home. These systems are also responsible for keeping folks comfortable. From our experience, about 50% of the existing home audit calls we get are utility bill related. The other 50% of people who call us do so because they are not comfortable in their home. Nine times out of ten, high utility bills and / or discomfort can be traced back to one of two things: the building envelope (air sealing and insulation) or the heating and cooling system.
When evaluating heating and air systems, inspectors use special tools to make these units operate safely, blow the right amount of air, deliver air to the right places, and are fine tuned for efficiency. Study after study has shown that heating and air systems are often poorly installed and inadequately serviced. As a result, most existing systems do not deliver their rated efficiency. We've literally seen "90%" efficient furnaces deliver little more than 60% efficiency! Perhaps more alarming are the health and safety issues that inspectors uncover, such as improperly venting combustion appliances and electrical issues. These types of safety problems put consumers at risk for carbon monoxide exposure and electrical fires.
Even if home owners don't suspect a problem, they should think about having their heating and air systems tested, inspected, and adjusted by an energy auditor or a well trained HVAC technician. As far as energy auditing goes, Building Performance Institute (BPI) inspectors offer the best of both worlds, as they are trained to identify efficiency issues and health and safety concerns like carbon monoxide hazards.
Read on to learn the cheapest upgrade you can make for the biggest return...