HERS RATINGS OR ENERGY STAR?

HERS RATINGS OR ENERGY STAR?

What’s The Difference And Which Is Better?

 

HERS or Energy Star

With energy efficiency becoming more and more popular, a question we often get by builders trying to stay competitive in the market is which is better, HERS Ratings or Energy Star?  What is the difference?

Both HERS Ratings and Energy Star are great programs and provide substantial benefits, it really depends on what is most important to you (the builder) and more importantly what the homebuyer wants.   Who is your competition and what are they doing?  What area are you building in?  Who is your target market?  So many questions that come into play when decided what energy program is best for you.  When it comes to HERS Ratings vs Energy Star, there are many pros and cons to both.  Let’s take a deeper dive into HERS Ratings.

What is a HERS Rating?

HERS stands for Home Energy Rating System.

A HERS Score is an Index used to tell how energy efficient your home is compared to a code built home.  The HERS Rating process is governed by a company called RESNET who oversees standards, training, quality assurance, and a formal complaint resolution process.  You can learn more about RESENT at http://www.resnet.us/  The HERS rating is a building block to many other rating programs, including Energy Star.

The score is basically a measurement that tells you how energy efficient your home is compared to a code built home. The lower the score, the more energy efficient your home is!  It’s based off a linear scale with 100 meaning the rated home has the same energy use as the HERS Reference Home which is based on the 2004/2006 IECC.  A HERS index of 0 means the home has net zero energy usage.  Thus, the home produces as much energy as it uses.  For example, if the HERS index on a home is 65, the home would be 35% more efficient than the Code built home.  See the picture to the left to get a visual perception of how the scale is measured.

How do I get a HERS Rating?

To get a HERS Rating, a Certified HERS Rater, (preferably Performance Point) will inspect your home and gather information to generate a score.  HERS Ratings consider energy usage from all areas of the house including lighting, appliances, framing, insulation, air sealing, water heating, and HVAC. One cool thing about a HERS Rating is you can even accurately estimate annual usage for a house.

What are the benefits of a HERS Rating?

One great aspect of the HERS Index that is important to keep in mind is, it is not pass or fail so it doesn’t hold up construction.  That is huge when it comes to production builders who are on a start schedule to keep up with their goals.   You also don’t have to pay to become certified or worry about finding a HVAC Contractor who is ACCA certified.  A HERS Ratings is a great marketing tool and way to show homebuyers the awesome energy efficient features you have and how it benefits them.  There are also Rebate programs out there for builders based of HERS Ratings.  Santee Cooper for example offers rebates for homes that score 85 or lower and meet specific criteria.  Learn more at https://www.santeecooper.com/residential/reduce-the-use-and-save/rebates.aspx

What is Energy Star?

Energy Star is a widely known energy efficiency program for residential new construction.   It is a trusted, government-backed symbol and program.  It has many benefits for the homeowner.  The Energy Star new homes program has been around since the 1990’s and is currently under version 3.

How do I get my home Energy Star Certified?

To become Energy Star certified, it’s important to partner with an Energy Rater before you start the construction process.  Go to www.theperformancepoint.com to find yours today. The Builder must get Certified through the Energy Star website at  https://www.energystar.gov/.  They have to watch a video and take a short quiz.  The HVAC contractor also has to be ACCA Certified. To learn more, go to http://www.acca.org/home.

What are the Benefits of Energy Star?

One of the major benefits for the homeowner is reduced energy costs.  On average, you save 35% more than the average code built home.  That can be substantial cost savings!  The average annual savings for an Energy Star certified home is $300!

Another value add is a greater ROI.  Energy Star increases the building value and gives you a greater resale value.  It also requires comprehensive air sealing and quality-installed insulation which helps to reduce leaks and drafts.  With less gaps and cracks, you end up having more consistent temperatures, minimizing warm and cold spots and improving comfort in the home.   ES provides a comprehensive water management system, including flashing, moisture barriers, and heavy -duty membranes to protect the home from moisture damage.   They also require fresh air ventilation.  A fresh air system provides a controlled amount of outdoor air combined with a high-performance filter to improve indoor air quality and in return reduces dust, pollen, and other allergens.  It also prevents mold build up from a home becoming too tight.

Crazy to think they want you to air seal and make the home so tight just to bring air back in the home, right?!  That’s what you call building science people.  There is a science to this madness.  And lastly but not least, you are helping save the environment.  Each Energy Star certified home reduces greenhouse gases by 3,700 lbs. per year compared to a code built home.  That is equivalent to 43 trees.    So, with all the benefits mentioned above for Energy Star, why wouldn’t you choose it over a HERS rating?

 Difficulties with Energy Star

Even though Energy Star has a million benefits to the homeowner, it can be a very difficult process.  Energy Star can be somewhat costly for the builder and HVAC contractor.     It is important for the trades involved to know what is required from the start of construction.  Many builders wait until they are about to insulate to ask for their home to be certified and often, it is too late depending on what type of framing they had or if pre-drywall has been hung yet.

Energy Star is pass or fail so if something isn’t done correctly during the process, you can fail your inspection which in turn holds up the next trade until the correction is completed.  Think about that for a minute.  You are building 500 homes in a year, with 20 different trade partners.  One inspection failed because the insulation wasn’t correct and they had gaps and cracks that needed to be air sealed. They fail inspection and can’t fix the items for 2 days.  The items finally get corrected and it passes inspection but now the dry wall contractors are busy and can’t get in for 3 more days which pushes back the next trade.  Now because of one failed inspection, you are weeks behind.  It’s a domino effect so it’s important for things to be done correctly the first time.  For a home to pass Energy Star, there is a checklist based off performance.  If you are building a custom home, the homeowner may prefer a huge fridge and outside shower over energy efficient appliances or LED lighting.  Which goes back to why it is important to know your target market and understand what is required before deciding which program is better for you.

Another huge hurtle we come across as a Third Party Inspector for Energy Star is collecting the checklists from the builders and HVAC contractors.  I can’t stress the importance and headache of this enough.  We are constantly chasing people down to get their checklists complete or correct.  We CANNOT complete the Energy Star Certificate without the checklists from the Rater, Builder, and HVAC Contractor.  So many times the HVAC company doesn’t fill out what is required and homeowner and builders are knocking our doors down for their Certs which makes us look bad.  So one thing I will say is if you choose to certify your homes as Energy Star, make sure you work with builders and trades you can trust to complete the process so you aren’t making promises to homeowners  you can’t keep.

Conclusion

Okay so you could build a home just as tight as an Energy Star home and not get it certified but get a HERS Score?  YES!  But then do you have to worry about your home being too “tight”? I’m so glad you asked… No it is not required to have fresh air ventilation with a HERS Score so you very well could end up making your home too tight.  Therefore, it is so important to consult a building scientist and get the advice you need to build an energy efficient home. There are many benefits to getting a HERS Rating and many benefits to certifying your home to be Energy Star Certified.

To learn more about Performance Point, go to our Facebook page at www.facebook.com/energyratersproven/

Click here to see a sample Energy Star Certificate

https://www.energystar.gov/ia/partners/bldrs_lenders_raters/downloads/NewHomesCertificate_11.07.13_SAMPLE.Watermark.pdf?c145-7763&597a-7c38

 


Go Green this St. Patty’s Day!

 

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 St. Patty’s Day is soon approaching so we wanted to share some easy tips and tricks for going green!  Of course, most of you think of the obvious on St. Patty’s Day… Green attire, parades, festivals, shamrocks, rivers dyed green, corn beef and cabbage ….maybe even green beer! What you may not think of, is how to practice “being” green this St. Patty’s Day!  😊  What are some easy little changes you can make this year to be more energy efficient and live a healthier, more sustainable life?
imgresOne of the easiest, most energy efficient tasks you can do to help save energy and lower your energy bill, is change your light bulbs in your home.  Invest in energy-efficient LED and CFL bulbs! They use up to 75 to 80 % less energy than traditional incandescent bulbs!! They also last longer and won’t burn out so quickly.  Why not, right?!

Blinds

 Have you ever thought as simple as opening your blinds during the day?  Yes, this applies to the cold winter months so it may not be quite as effective for St. Patty’s Day.  Although, here in Charlotte and in the Midwest, they are calling for snow the weekend before St. Patty’s Day so I figured it was worth adding it to the list.  About 10% of energy can be saved on heating when you open the blinds and let the sun shine through! And who doesn’t love natural light during the day? 


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Celebration Time! If you are having a party or friends over to celebrate, provide coolers with ice Pic for websitefor people to put their drinks.  Opening and closing the fridge frequently can raise your energy bill. Another easy tip is to have snacks that don’t need to be refrigerated. Plus, who wants food that should be cold after it’s been sitting out all day at a party?!  Gross!

 

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Shower VS Bath:  Take a shower instead of a bath.  I know you probably thought it would be fun to dye your bath green with a bath bomb from Lush and post it on Snap chat or IG, but if you want to truly be green this St. Patty’s Day, then we suggest you take a shower instead. Taking a bath can waste up to 30 gallons of water, whereas a five-minute shower uses closer to 10-25 gallons. If you really want to get crazy with it, you can install a low-flow shower head which can lower your impact to only two gallons per minute. I told you this was easy!

 

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Cold is better! That statement isnot always true in my opinion but in the case I am about to explain to you, it most certainly is.  80-90% of energy goes into heating water to wash your clothes.  Use cold water instead!  It will also help save you hot water if you decide to take a shower right after you throw in a load. It’s a win win.

 

Hang Dry…. I’m sure most of you went out and bought a cute new outfit to wear for St. Patty’s Day! And most of you (women) will likely wash it before you wear it since who knows how many people have tried it on.  So, as mentioned above, use cold water when going through the wash cycle.  Once it’s finished, hang it dry instead of putting it in the dryer.  Up to 2-3 kg oDIY_Lucky_T-shirt_2f carbon emissions are released every hour your dryer is in use.  And I’m sure some of you have those dryers that don’t work right so you have to put it through two cycles just to get it dry. So annoying, I know… Also, that is a lot of carbon emissions being released in your home. As a result of air drying, are using less energy which in turn provides you an even lower energy bill.

 

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Small things add up and make a big difference! Even if you can’t commit toimgres all the actions above, doing a few of them will make you one step closer to living green! 

 

Happy Saint Patrick’s Day! Have fun but most importantly….be safe and be green! 

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Have Yourself a Merry Energy Efficient Christmas

There are numerous things that can make your energy bill triple over the Holiday months and it isn’t just the cold weather.  With the technology and electronics being used in the world today, there are various ways we can contribute to that increase in our utility bills this time of year.  We decided to share with you some tips and tricks on how to save and cut holiday energy costs. 

 

c9multiChristmas Lights!  Before you untangle those traditional bulbs, consider LED lighting or Rope Lights. Not only do LED lights longer lasting, but they use less energy. You could reap up to 70-90% energy savings.  Plus, they look great on trees and outdoor displays.  Another option would be rope lights.  Typically, rope lights use miniature incandescent bulbs spaced apart in a flexible plastic tubing.  There are LED Rope lights on the market but if you can’t find them, the standard ropes work great too.  They only consume about .5 watts of electricity per foot and can last more than 20,000 hours.

 

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Time your lighting. Whatever lights you use, leaving them on all day or after you go to sleep runs up your electric bill. If you have a hard time remembering to shut off or turn on your lights, invest in a timer that will do it for you. You can choose the time your lights come on and how long you want them to stay on. This has the bonus of making it appear that you are home when you go away for the evening.

 

Thimgresinking about getting a new Christmas tree? Save energy with a fiber optic tree. These trees use a single bulb to transmit electricity along tiny fibers throughout the branches. The fibers light up the entire tree, often in alternating colors, and stay cool to the touch. With only one 5-20 watt bulb consuming energy on your tree, you are saving money and eliminating the task of hanging and removing lights.

 

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Candles are a great electric-free option that can be used in outdoor settings as well.  Even with shorter daylight hours, solar-powered luminaries, strings, and ornaments can soak up enough sunlight to illuminate your yard or tree for plenty of enjoyment. If you just can’t give up tree lights, cut down the amount by decorating with shiny ornaments, garland or tinsel that reflect light and add brilliance. Turn off overhead lighting when your tree is on, and the soft glow will still provide enough light to navigate the room.

 

Even if you are competing to have the best neighborhood Christmas lights, it doesn’t mean you should have to face the worst electric bill. Keep energy efficiency in mind during the holidays, and put a little extra holiday cash in your pocket!


10 Energy Saving Tips To Gobble Up This Thanksgiving

 

With help from Performance Point, you can ensure your electric bill will look as good as your Thanksgiving dinner.

1. If a big group of people is expected for dinner, lower the thermostat a couple degrees before the guests arrive. The oven will keep the house warm, not to mention people generate heat as well!

2. Check the refrigerator/freezer doors to make sure they are sealed tightly. This will keep the cold air in and the warm air out. To test, close the refrigerator door on a dollar bill. If you can slip the bill out easily or if it falls out on its own, the door requires adjustment, or the gasket needs replacing.

3. Allow hot foods and liquids to cool before putting them in the refrigerator. Uncovered, hot food and liquids release vapors that make the refrigerator work harder. Use a lid or plastic wrap to cover the food and place in the refrigerator after cooling.

4. Use a “lids-on” approach to cooking. Tightly fitted lids on pots and pans help keep heat in, enabling you to lower the temperature settings and lessen the cooking times.

5. When boiling liquids, start by using the highest temperature settings to reach the boiling point. Then lower the heat control setting and allow the food to simmer until fully cooked.

6. Use ceramic or glass pans — you can turn down the oven’s temp by up to 25 degrees and get the same results. That’s because these materials retain heat so well, they’ll continue cooking food even after being removed from the oven.

7. When preheating your regular oven, time the preheat period carefully. Five to eight minutes should be enough time. There is no need to preheat for broiling or roasting.

8. When using an electric oven, cook as much of your meal as possible in it at one time. Foods with different cooking temperatures can often be cooked simultaneously at one temperature – variations of 25 degrees Fahrenheit in either direction still produce good results and save energy.

9. When all the cooking is done, don’t use your oven’s self-cleaning cycle unless a major cleaning job is needed. Wipe up minor spills and splatters with a damp cloth. When you do use the oven’s self-cleaning feature, start the cycle right after cooking, while the oven is still hot, or wait until late evening hours when use of electricity is lowest.

10. Finally, use your dishwasher. It saves energy and water, so only hand-wash things that aren’t dishwasher-safe. Wait until you’ve got a full load before starting the dishwasher. Be sure to stop the appliance before the heated dry cycle; just open the door and let your dishes air-dry.

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Technically Speaking

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Not too long ago, while performing a framing and insulation inspection of a single-family home with a builder friend, we were approached by the future homeowner of the house. I had just concluded my explanation of air movement through fiberglass batt insulation. The homeowner caught the tail end of my statement and exclaimed, “You sound like a freaking scientist!”  Brad, the builder, acknowledged the remark with, “Well, he kind of is a scientist; a building scientist.”  The fact of the matter is, there are actually alot of scientific principles involved in construction today, especially when it comes to OUR industry of energy efficiency and home performance!

I could have, very easily, made that homeowner’s head spin circles with a slew of technical terms, but that’s not what is important to me, the builder, OR the homeowner. Empathizing with an audience is critical to educating the audience. After graciously accepting his compliment, I paused and reiterated my point in a manner that would more easily be mentally digested by the homeowner.

With so many technical concepts involved in our day-to-day field work, its easy to forget who we are talking to!  The recipients of our inspection reports may not be as excited about the value of “that bathtub airbarrier”, and the critical role it plays in the reduction of heat convection. More often, the builders we talk to are most concerned with what material to put where, and who to call to get it put there!

Our field staff at Performance Point strives to communicate with, and educate, everyone we meet, whether its on the jobsite, a trade show, or at a neighborhood cookout. Its how we present our expertise in building science, that allows for optimal success in our market!

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A picture is worth how much???

A picture is worth a thousand words….right? 

That’s my Dad and me on a recent trip to Myrtle Beach, riding the Skywheel…a monster Ferris wheel, the 2nd tallest in North America when it opened in 2011.  You’d think we were both in the process of coming unglued, experiencing sheer terror while being propelled up and over the sands of Myrtle Beach and its boardwalk.  But…thankfully this picture is misleading.  Anyone who’s been around the 2 of us “Blair Boys,”  as we’ve so affectionately been dubbed, knows we love a good prank and we’re always looking for whatever levity can be found in the moment.

The unwitting recipient of this prank?  My partner, Susan, who freaked out at the last minute when she saw upon arrival how the wheel soared ominously overhead.  When back on the ground, and with straight faces, we told Susan that my mother had snapped a pic of us at just the right moment…a moment where we ever so briefly lost our bravery.  We confessed that we wanted to deny being even mildly afraid…but the picture made it impossible…and sorta gave us away.  We then showed her the picture.

Dad and I were put on KP duty the rest of that vacation…

So, yes, a picture can be misleading…sometimes unintentionally, sometimes not so unintentionally.  In the world of infrared photography, and what defects it can detect in your home…a picture can often NOT be worth a thousand words.  A picture made from an infrared camera is called a “thermogram.”  If used with a thorough understanding of building science, as well as being trained to interpret what is in the thermogram, that thermal camera can be an extremely powerful tool.  If used by someone without the proper training, it can at least be a tool of misleading information borne simply out of ignorance…and worst, a tool for deliberate deception.  This is often the case with any gadget offering advanced technology…they can come off as having magical powers…unfathomable abilities.  A quick google search for “infrared and ghosts” will introduce you to a popular example of this.  It is believed by many in the paranormal CSI world that IR cameras can detect ghosts.  This is simply due to the way the infrared spectrum of light behaves differently around different materials…some will absorb, some reflect, some emit back quickly, others slowly. The heat from our body gets absorbed by most materials inside our home…but reflects off of glass and most metals.  What these CSI ghosts hunters are actually seeing is the reflected heat of their own bodies…passionately stimulated by the lure of finding that spooky ghost!

In an effort to make this blog entry user friendly, and actually helpful, I’ll stay away from some of the mind-numbing geeky science involved with our discussion and focus on a handful of the most common errors of misinterpretation of thermograms used in the assessment of building structures.  I’m pulling from my own professional experience as a thermographer in the field of residential energy efficiency testing, troubleshooting, and weatherization.  My hope is that if you’ve been handed a home inspection with any use of thermography that you’ll be a better informed consumer of this service, and less likely to be scared by misinformation.  (Caveat…not all thermograms in home inspections are misleading…even the ones that are a sincere attempt to point out what is thought a defect.)

Wood be a problem….

It “would” be a problem, if the insulation in our walls and ceilings were the same as wood.  Thankfully, fiberglass, cellulose, or foam insulation is a much better insulator than wood.  If it wasn’t, we’d all live in skinny log homes. (Thick logs provide what’s called the  “thermal mass effect”…its own & efficient kind of protection against the elements in the right climate).  But since the relatively thin wood framing in our homes insulates less than properly installed insulation in-between…it usually looks different in a thermogram.  If there’s enough temperature difference between inside and outside of the home…the insulation will resist heat transfer much better than the wood.  Therefore we will see this difference with a thermal imager…which is merely detecting the difference in the surface temperature along the wall…it’s not seeing “into” the wall.

The paragraph above has the clues we need about how a thermogram can be misleading and misinterpreted.

  1. Wood framing in conventional framed homes resists heat less than properly installed insulation.
  2. More wood, side by side, equals even less thermal resistance in that area…than if a single piece of wood were used.
  3. If there’s not enough difference between indoor and outdoor temperatures, you will barely see any differences in the framed/insulated wall…if the wall is not resisting heat transfer from one side to the other…we’ve lost our special powers.
  4. If there’s NO differences between indoor and outdoor temperatures, then leave the camera at home.
  5. If the insulation is not properly installed (no compression, gaps, or voids) then we’ve got some real issues of differential diagnosis to deal with.

Thermal_01   Thermal_02

What we see above are good examples of a normal, and properly insulated wall.  The yellow colors indicate the warmer surface of the insulated bays between the studs, and the green/blue lines are the studs that are passing the indoor heat more quickly through the wall…therefore a bit cooler.  Now…notice the darker blue line going horizontally in the left picture?  Uh oh….do we have a defect of insulation?  ..all somehow occurring along the top of the wall?  Or in the picture at right, do we have a strip of insulation missing going vertically? No, and no.  These are all examples of what’s called “thermal bridging” that wood passes heat faster than insulation, and that more wood next to each other passes even more heat.  The horizontal and vertical dark blue lines show the double stacked 2×4 at the top of the wall, and the vertical shows the typically framed corner which uses more studs than the rest of the wall. Most folks using a thermal camera for a building inspection would not make this very basic error, but I’ve seen it done more than once.  Can you imagine ripping out the drywall only to find wood where you thought there was an insulation defect?

Most defects of insulation….that would actually make a real difference in the comfort and/or energy bills for your home are pretty obvious in a thermogram.  Look at the example below.  These homeowners were complaining of comfort issues in their bedroom.  For some reason it was harder to keep at the same temperature as the rest of the house.  After screening the non problematic areas of ceiling, and getting its baseline temperature, I locked in the temperature range of the camera…so it did not automatically adjust the range for different conditions.  That way I could compare apples to apples…ceiling to ceiling temps rather than each ceiling being simply relative to its adjacent wall temperatures.  If there was a ceiling in the house that had any temperature difference from the others…I’d be able to see it clearly.  As I walked down the hall, and turned the corner into the master bedroom, my camera turned bright blue, indicating a colder surface than the other ceilings.  This whole master bedroom ceiling was not insulated!  Is it not obvious, in the thermogram below, that we have a problem?  If your inspector includes a picture like this, then you have a problem…even if you don’t live in Houston.

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This thermogram actually shows a lot of interesting data…thermally speaking.  Notice the warm insulated bay walls, thermal bridging of top plate (2 studs on top of wall system), insulated bays of soffit surrounding the non-insulated recessed ceiling, the “hot” rectangle of the heat register in the ceiling, and most interestingly…the reverse pattern of warmer/cooler in the ceiling joists and bays of the recessed ceiling.  Now here, the wood is the better insulator…the 2x piece of wood insulates better than a piece of drywall with nothing on it.  The light blue is warmer than the dark blue…

Aside from this dramatic example of missing insulation, a more common thermogram on an inspection report are minor areas of different colors that may simply indicate a section of insulation is compressed (therefore has less pockets of air that provide the heat resistance), gaps of insulation, variations of thermal bridging, wiring and plumbing interruptions within the insulation, etc.  This is where building science is needed…to understand what may be going on.  If an inspector has raised the concern that a thermogram indicates a defect of insulation it should be evaluated further to determine the nature of the apparent problem, and whether it would actually be a cost effective thing to fix.  If you’re already living in your home, and want to button things up, stick to the obvious areas, or ones that are giving comfort problems.

Convection is great…in an oven…or with big fans that sit in doorways…

Don’t youunnamed love a convection oven?  Faster, more evenly cooked turkey on Thanksgiving is what immediately comes to my mind.  When that convection oven’s fan whirls the air around inside…the moving hot air transfers more heat all around whatever you’re cooking.  Moving air transfers more heat than still air.

What does this have to do with our homes?  Besides enjoying a great turkey, it simply means that air movement in and out of our homes also affects the energy bills and comfort we feel inside them.  Perhaps the most common complaints are cold drafts…

A thermal camera can actually see convection…or moving air under the right conditions.  To be more precise, what it sees is simply the “effect” the moving air has on the surface it’s blowing across.  The moving air will bring the adjacent surface temperature closer to its own temperature.  Remember, a thermal camera only sees temperature differences along a surface…so if the moving air is the same temperature as the surface, we won’t see any difference.  But have the cold outside air blow across an interior surface and voila….we have a really wispy thermogram!

 

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Here is a picture of an all too common defect inside our homes…the dreaded can light!  Major punctures through our homes thermal boundary.  But if you’re an owner of a new home, most likely this inherent “defect” in the thermal boundary has been minimized.  Newer ICAT units (insulation contact, air tight) allow the insulation to be placed in direct contact with them, and are theoretically air tight.  Theoretical because the unit itself is tight, but it all comes down to proper installation and sealing of the big hole in the drywall that’s holding the unit.  Energy Star requires these open joints around can lights to be sealed…because if they’re adjacent to attic space they are a direct avenue for air movement in and out of the attic and into your home.  Who wants air exchange from 4,8 or 10 holes in the ceiling between the attic and living space?  Kind of inspires visions of “beam me up Scotty.”  Imagine a sudden gust of wind lowering the pressure inside your home relative to outside, and some creature from the attic being teleported into your living room!  Or worse, some freak occurrence of nature that dramatically raised the pressure inside and grandma got beamed up into the attic!

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Although most inspectors using an infrared camera know that can lights are notorious for air leakage, fewer know about the difference between heat transfer through solid surfaces (conduction), through air movement (convection), and that different materials emit their absorbed heat differently (radiation).  In the thermogram above we have a good example of convective heat transfer…the wispy feathery pattern that is diagnostic of air movement.  This is a simple problem to fix….caulk the perimeter of the can to the drywall.  If the wispy lines weren’t there we’d most likely see just a light blue ring around the can light.  Uh oh…more problems?!  Still air leakage?  No…this is where the thermal camera in untrained hands can be problematic.  Most of the time, that ring around the can light is some type of metal, and if it’s metal it will show up differently in the thermogram.  “But it’s blue so it must be a problem,” is the thinking of an untrained eye.  There’s a lot of different blues in this thermogram…but only some are of concern.  The light blue ring…simply indicates that the metal emits radiation energy much less than the wood around it.  We’re creeping ever so closely to mind-numbing nerdy science here…but the name of this in case you hear it somewhere is “emissivity.”  If you’ve heard of Low-E windows….E is for emissivity.  The lower the emissivity of a material, the less heat energy it radiates…so it shows up differently in the thermogram.  Whenever there’s an obvious and distinct difference of colors in a thermogram, you have to rule out the effects of emissivity differences.  You may wonder about those blue streaks?  Air leakage through the T&G ceiling?  Most likely no…although I have seen occasions of this.  In this thermogram I would say the slightly lower temperature in the groove is simply the difference of thickness in the wood.  If there was convection…once again we would see wispy features.

So what about convection of big fans in doorways?  With the aid of a contraption generally known as a blower door, your home’s interior pressure can be lowered…relative to outdoors.  A blower door is simply a frame that fits in your exterior door opening, covered with some type of plastic canvas, and has a big fan in it.  To properly detect air leakage with an infrared camera…you gotta use a blower door.  A red flag should go up if you read a thermal inspection report where air leakage is cited as a problem…and you know they didn’t use a blower door.  Since the blower door lowers the pressure inside your home, relative to outside, any sources of air leakage in the thermal boundary of your home will start sucking in air to balance the air pressure.  And as long as that outside air is different enough temperature wise than inside air…the thermal camera will see the fingerprints of convection.  This artificially produced convection with the blower door & thermal camera, is one of the standard protocols, and most often used, for the detection of air infiltration into a building structure.

So is a picture worth a thousand words?   I’ll appeal to how my grandfather responded to my question about whether he wore briefs or jocky shorts.  Without batting an eye he said, “depends.”

Yes indeed….well said grandpa.  However, being navigationally challenged, a picture is worth more than a thousand words to me.  I’ve gotta see a picture…because someone verbally reciting directions puts me into a trance.  Thank God for GPS….