Global Climate Solutions

By Ryan D. Hottle

If you don’t know what an “Energy Audit” means, don’t worry—it has nothing to do with the IRS!  It does have to do with saving significant quantities of energy and money, though.  Many people are surprised when they realize that commercial buildings and homes make up the most energy-intensive sectors in the North America.

Essentially, an Energy Audit is a quantitative inspection of a building’s performance in terms of energy, health, safety, soundness, and comfort.  The goal of the audit is to identify critical areas and opportunities for energy savings while simultaneously ensuring that health and safety is maintained to the highest levels possible.  

This is the first of three blogs I will be posting on Energy Auditing.  In this blog let’s take a look at why an Energy Audit is a good idea, and what the general tools of the trade are in order to give an idea of what you might expect from an audit. 

IS A HOME HEATING CRISIS ON THE HORIZON?

The recent dip in prices of energy fuels commonly used in households, such as natural gas and home heating oil, are likely to only be a short-term trend that are a function of market instability rather than actual supply-and-demand economics.  Thus, the relief from lower fossil fuel prices is probably not going to last for long.  Home heating costs will invariably continue their upward cost trend as we reach inherent limits imposed by the peaking of world oil and gas reserves. 

Despite the recent downturn in oil prices, the evidence is overwhelming that rising oil prices will be a continuing trend as geological limits are reached.

Whether it’s this year or next or five years from now when declining oil and gas production coupled with declining real incomes translates into a serious home heating crisis for Americans, I would strongly encourage anyone who owns a home or small business to think seriously about investing in energy conservation and efficiency.  It’ll pay out a heck of a lot more than the stock market these days, I’ll guarantee it!  

Perhaps even more important is the fact that energy conservation and efficiency are the two most critical aspects of lowering CO2 emissions and therefore are critical to help mitigate the climate crisis.    

Energy Use Patterns in Average U.S. Household

GOAL OF AN ENERGY AUDIT

The goal of an energy audit is to identify and quantify opportunities for savings, which is really a fancy way of saying figuring out how to tighten up a house and make it as efficient as possible.  How much insulation does the home have?  Is it worth investing in adding more insulation?  What kind of electricity use is associated with lighting?  Would switching light bulbs or fixtures make sense?  How efficient is the furnace or boiler and is it a candidate for replacement?

These are the types of questions that an energy audit should be able to quantifiably answer.  The audit should give the home or business owner a list of energy efficiency improvement and conservation strategies ranging from the easiest and most cost-effective to the most expensive.  It is then up to the home or business owner to decide which of these to pursue as their overall strategy to reduce energy costs.  

You can perform your own energy audit on your home or business if you have a good overall understanding of building performance and efficiency.  While it’s not rocket science to determine insulation levels in your attic, a thorough energy audit is fairly involved process and most people would probably benefit from hiring a professional energy auditor.   Additionally, the professional auditor benefits from having certain diagnostic tools which allow for a more in-depth inspection than a homeowner could typically accomplish. 

The most critical aspects of home efficiency are:

1) Conductive Losses: How much insulation are in the walls and attic?  Are there any “holes” in the thermal boundary of the structure? What are the best methods by which we can improve insulation levels?

2) Convective Losses: How leaky is the house?  How much air can directly come in and out of the house and where are these leaks located? What are the best methods for reducing air infiltration?

3) Heating Efficiency:  How efficient is the heating unit and the domestic hot water unit?  Should they be replaced?  If replacement is not practical or cost-effective, what steps can be taken to improve efficiencies of existing systems? 

4) Appliance and Lighting Efficiency: How efficient are the appliances?  Are they necessary?  What kind of paybacks might we expect if we were to replace, say, the refrigerator or freezer or putting the exterior lighting on a timer, or replace the lighting?

INCREASING YOUR KNOWLEDGE

If you choose to hire a professional Energy Auditor to conduct an inspection on your home or building, I highly encourage you to be present and to take a very active role throughout the audit.  Pepper the auditor with as many questions as possible and take notes throughout the process.  Remember, sometimes even an experienced auditor can overlook critical problems or solutions.  Another reason to be on site is that often the buildingowner will know critical things about the building that may not be apparent at the time of the audit.  For instance, does basement flooding occur with heavy rains, or does the furnace tend to turn on and off very quickly (i.e. “short-cycle” which can lead to significant inefficiencies)?

You will have a much better idea of what the Energy Auditor is up to and how the process works if you have a basic understanding of the tools and techniques of building science and energy auditing. 

Two excellent information are Larry Kinney’s “Energy Auditing Techniques” and John Krigger’s “Residential Energy”.  (If you want to conduct an audit on your own home or business, I would make these “required reading.”)

TOOLS OF THE TRADE

A professional Energy Auditor should have a toolkit of diagnostic equipment used to quantify various aspects of efficiency in the home.   Generally, these will include the following items:

The Blower Door

The Blower Door used for determining the leakiness (convective losses) associated with the building.  This diagnostic tool is essential and should be included in any professional audit.  This will give an auditor the number of cubic feet per minute (cfm) existing a house at a given depressurization constant (typically -50 pascals.)  A pascal, is a measure of pressure equal to one Newton per square meter.  Roughly the equivalent of a “mouse fart” as Dr. Kinney would say;)

The do-it-yourselfer might think about contriving a blower door “effect” simply by turning all exhaust fans in the house (bathroom fans, stove fans, etc.) and possibly setting up a few box fans to further depressurize the house.  Note this will not give you a CFM measurement but will allow you to feel for infiltrating air currents.  Doing this during the cold-season will allow one to more readily feel infiltrating air. 

The Gas Detector

The Combustible Gas Detector is used for determining if there are leaks in natural gas or propane lines, this is another essential piece of equipment that the auditor should have to determine health and safety of the home.  The device makes a steady cadence of beeping sounds when there is no gas present.  If gas is present the noise level increases dramatically creating a more rapid cadence and higher pitch sound.  Most often gas leaks are discovered around poorly fitted natural gas pipes that simply need to be re-doped and tightened. 

The Flue Gas Analyzer

The Flue Gas Efficiency Analyzer is used for determining the efficiency of combustion appliances including furnaces, boilers, water heaters, and stoves.  Again, this is an essential piece of equipment in order to determine health, safety, and efficiency.  High CO (carbon monoxide levels) pose a significant threat to health and safety with more than 100 people dying from unintentional exposure each year in the US.

The Manometer

The Digital Manometer (aka pressure gauge) is used in a wide variety of applications to measure differences in pressure.  This is the device that the auditor will hook-up to the Blower Door in order to find out how leaky the home is at a given pressure.  By using this device with the Blower Door running, the auditor is also able to discover how much rooms or spaces such as garages are communicating with the outside.  The device is also used when analyzing combustion devices in order to ensure that proper draft levels are achieved when venting combustion gases to the outside of the building area. 

The Infrared Camera

An infrared camera is a powerful tool that allows the auditor to quickly pick up on temperature differences which allows for quick inspection of conductive and convective performance.  An infrared camera is incredibly useful but not absolutely necessary (a more simple and inexpensive infrared gun which costs $50 instead of $5,000 can be used.) 

The Water Weir 

A low cost water flow meter can be made with a couple bucks for a cheap plastic pitcher and an hour or two of fine tuning with a drill puncuturing holes up one of the sides of the pitcher.  When held under a constant stream of flowing water the weir will fill up to a height at which the outflow (the water flowing out of the holes where holes were drilled into the pitcher) is equal to the inflow (the amount of water flowing in) and thus stabalizes at a particular height.  If properly guaged, the weir will read the output coming from a shower or faucet.  This enables the auditor to know whether a replacement of shower heads or the addition of aerators to sinks may be in order.  

FINDING AN AUDITOR

A list of auditors can be found on through several organizations which require auditors to meet certain training and testing minimums.  The two most prominent of these are HERS/RESNET and the Building Performance Institute.  Generally, a home or business owern can expect to pay somewhere between for $200 and $400 for a comprehensive audit which should take at least 3 hours.  

Take into consideration whether the auditor conducting the inspection is independent or whether he or she is working for a company that also does weatherization work after the audit is complete.  The auditor who is working for the weatherization company obviously has an incentive to sell jobs, which can mean that the audit’s emphasis may be skewed to additional services that the company provides instead of the most cost-effecitve opportunities for the home or business owner.

As energy conservation and efficiency guru Larry Kinney says, “Opportunity follows waste.”  Which is to say that if your home or business is largely ineffecient, then there are likely to be significant opportunities for savings.  A quality energy audit followed up with quality retrofit work can lead to dramatic savings–often paying for themselves within 3 to 10 years.  

The most important opportunity is not saving money or energy, however.  The most important opportunity is reducing CO2 emissions as we face the most critical threat that has ever faced humanity: global climate change.  

In upcoming blogs, I will be exploring I will be exploring the most cost-effective strategies homeowners and small-business owners can take to reduce energy consumption, as well as strategies of heating and powering homes that could lead to a net reduction of CO2 emissions.  Stayed tuned.

We have but one beautiful world to protect and precious little time to do it in.  What we choose to do–or not to do–in the next five to ten years will make all the difference.  Be prepared to work hard and to work together–that’s the only way we’re going to win!