Energy Audit-Tools of the Trade

An energy audit is an inspection and analysis of how a building uses energy.  To get an accurate analysis, tools are needed to perform testing.  You would think that a blower door and thermal imaging camera would be my most commonly used tools during an audit, I do use them often, but there are a couple I used more.  This posting is all about my energy auditing toolbox.

Health and safety will always trump energy conservation and something I can easily measure in a home is carbon monoxide.  This odorless and colorless gas can be harmful and even deadly in high concentrations.  I own a portable, wearable CO monitor will alert me if CO is at a dangerous level and it will also indicate the concentration level.  Another health and safety tool I own is a gas detector.  This portable device “sniffs” for gas leaks.  I rarely need it, but it is useful in pinpointing the source of a gas leak if I suspect there’s one during an audit.

When on an energy audit, sometimes my senses are the tool.  Sight, hearing, touch, and smell are all used which often lead me to needing other tools.  An example is a musty odor.  That “damp” smell will require some investigation.  I start by checking the humidity level in around the location of the odor which is accomplished using a humidity/temperature pen.  I may also need to check moisture levels of building components.  My moisture meter is a non-contact/pinned version.  I often start with the non-contact option so that no finished surfaces are damaged but move to the pins if I find an area of concern.  Both my tools are made by Extech Instruments.  Neither are high end models, but they get me in the ballpark with the information they provide.

How about my most used tool?  The majority of energy audits I perform are high electricity bill complaints meaning I’m testing is a home’s electrical service panel and plug-in equipment for usage.  A clamp-on ammeter is my most used tool.  Mine will test amperage being drawn by either an individual circuit or by the entire panel.  I also have leads to check the voltage coming into a home which can also be a reason for a high bill.  For checking usage of individual plug-in appliances, I have a Kill-A-Watt Meter.  The information gained by these two meters will give me a snapshot of usage at the time of the testing.  If I need more details, I request historical usage data, the electricity provider I work with can get me hourly meter readings showing me usage for any period of time.  Helpful if the usage testing isn’t conclusive during the audit.

Having a blower door is a must for an energy auditor.  Air leakage has many effects on a home.  Cost of heating and cooling, comfort, durability, humidity levels, sound transmission, odors and indoor air quality can all be affected by how tight a structure is, and the only way to know is to test.  I own two blower door kits, a Minneapolis Blower Door and one made by Retrotec.  I often control the blower door by using either a tablet or laptop computer.  My Microsoft Surface comes along on every audit.  I can also control the blower door with my cell phone.

Retrotec’s model 5100 and DM32 manometer.

Measuring a building to calculated square footage, volume and surface area is needed to perform a blower door test, or if needed, a heat loss calculation.  The easiest way to measure is by using a laser measuring device.  Point the laser at a surface and you get a measurement from the laser to that surface.  Fast and easy, but does not always work, especially outdoors in bright sunlight where you cannot see the laser.  Sometimes a measuring wheel or just an old-fashioned tape measure is needed.  I use all three. 

The blower door will indicate how “tight” a home is, but other tools are used to find the air leaks.  The most common way is by using a thermal imaging camera.  This type of camera is “seeing” temperature differences in areas of its field of view.  When used during a blower door test, the temperature differences are often air leaks, but they could also be indication of a thermal bridge or even an area of higher moisture content such as a water leak.  The drawback with a thermal imaging camera, there needs to be a temperature difference between inside and outside the home.  Another way to check for air leakage is by using smoke.  I own a smoke pencil, a smoke puffer, and a theatrical smoke generator.  All different tools to visualize air movements.

Occasionally I need to test small area of a wall or ceiling that contain a penetration, such as an outlet, switch box or heating/cooling system grill.  These “holes” in the air control layer can be sources of air leaks if not sealed correctly.  A pressure pan used in conjunction with a blower door test will indicate if the penetration is leaking air.

The brain of a blower door kit is its manometer or digital pressure gauge.  This tool has many other functions such as testing pressures in forced air heating and cooling systems, checking natural pressures inside a home in relation to outside or with relationship to adjacent rooms.  The manometer can even be used to check balance in mechanical ventilation systems such as an energy recovery ventilator (ERV) or heat recovery ventilator (HRV).  The center gauge is an early analog blower door manometer from around 1990.

Another tool I own that is becoming more common in building testing and commissioning is one that tests the tightness of ducts.  This tool is designed to either pressurize or depressurize a duct system to determine air leakage.  Current building codes require duct tightness testing anytime a duct leaves the conditioned space of the home and I have heard of some home certification programs requiring that all ducts be tested whether they leave the conditioned space or not.  This type of testing is best done before the ducts are concealed by wall and ceiling finishes, but the test can be completed anytime.

Speaking of the commissioning of a home.  Testing of exhausting equipment such as bathroom and kitchen exhaust fans is often overlooked.  I use a couple different flow hoods that allow me to verify the CFM rate of an exhaust fan.  You can read more about exhaust fan testing here. (Link to my recent article in GBA about Exhaust fan testing.)

A tool I own but have not used in several years is a stack gas analyzer.  This device analyzes flue gases to determine if the combustion appliance is operating efficiently and at the proper fuel to air ratios.  The reason I no longer use this piece of equipment is I be will not the person making any adjustments to the equipment, so I recommend having annual maintenance completed on the equipment by someone trained to tune, adjust, and repair combustion appliances. 

Sometimes I need to look into tight places, in walls or inaccessible attics.  Down unfilled concrete blocks or into a pipe.  I own a small, older borescope camera called a SeeSnake.  This camera on a flexible rod and works well in tight and inaccessible places.  The model I have won’t take a photo, but just a live view is often enough to find a problem.

My cell phone is another tool I often use during energy auditing.  I have apps installed to help the process such as one that calculates dew point temperatures, a couple that will allow me to control my blower doors remotely and of course a weather app, calculator, and the phone’s camera.  I also use several photos stored in the phones memory when providing homeowner education.

These are the energy auditing tools I have been accumulating over the past dozen or so years, many will cross trades.  What diagnostic tools are on your wish list?

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