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3799 Main St. #87024
Atlanta, GA 30337


Advanced residential construction and home improvement consulting and owner's advocacy in Atlanta, using the latest building performance diagnostic and modeling techniques and tools. Airtightness, insulation, HVAC, ventilation, moisture, and air quality and EMF consulting for homeowners and building professionals alike.


Home performance articles and stories from the field with internationally respected building forensics guru Corbett Lunsford at the Building Performance Workshop. Hear new episodes of the Building Performance Podcast, see new videos from the Home Performance YouTube channel, and learn all about how diagnostic testing (more than an 'Energy Audit') can make home improvement and new home construction a proven process!

Filtering by Tag: home energy expert

Tour of the Building Performance Workshop in Atlanta

Corbett Lunsford

Welcome to the inaugural tour of the real life Building Performance Workshop on our high performance homestead in Atlanta, Georgia! From the translucent walls and roof to the airtight, insulated and dessicant dehumidified Dry Vault inside it, everything here is about making the invisible dynamics of building performance visible. Stay tuned for the blower door test, infrared thermal scan, air quality testing, and much more when the Workshop is built!

Dear Corbett: How Long Should My A/C Ideally Run?

Corbett Lunsford

Hi Corbett,
How long should the air conditioner run in a given day?  The upstairs zone was running for 16 hours yesterday, and 10.5 and 11.25 each of the days before.  Is that reasonable amount of time for the A/C to run given the recent summer temperatures?  We are still trying to get the developer in to fix the ductwork, and figured this might be an symptom of the problem.

Hey Graham!
Great question- your air conditioner is actually designed to run continuously when it's hotter than 89 degrees F outside.
The A/C's job is to both COOL and DRY the air, and if it's too big, it doesn't run long enough to wring the humidity out of the air. This leaves you with a muggy house, where you keep lowering the temperature to try to get comfortable.
So don't be concerned when your air conditioner runs for long periods on hot summer days- that means everything's working the way it's supposed to!
Looking Forward,


Corbett Lunsford

For my own company to be successful in the home performance industry, I strive to distill complex concepts and practices to their most essential and basic elements.  This does two things:

  1. It enables a professional to keep a cool, clear head when faced with complicated challenges in the field
  2. It helps frame the way we talk to our clients about our work (clients, professional or otherwise, tend to tune out when we get technical)

In the interest of keeping it simple, therefore, let's take a tour through all of Home Performance Contracting in a 4-3-2-1 approach. Here it is:


I describe Home Performance to my clients, and to myself, with four basic elements:

  1. Heat Flow (which everyone thinks they understand, though they generally don't)
  2. Air Flow & Pressure (two sides of the same coin, which very few building professionals think about deeply, even in HVAC)
  3. Moisture (damaging the home's durability more effectively than almost anything)
  4. Air Quality and Safety (including carbon monoxide, electricity, and structure)

This list is in increasing order of importance.  You'll notice that the two elements which have to do with energy efficiency are at the least important end of the list.  This is why your title is better defined as a Home Performance Expert than an Energy Efficiency Expert.  People will continue to call it 'Energy Auditing' when you're testing, but if you can keep reminding them that you're doing so much more than saving energy, you make yourself more valuable.


Before you whip out your tools and get to work, always remember that your most valuable tool is your own experience and your senses, and taking time to think.  There are three stages to any really valuable activity in this field (or any field, as far as I'm concerned):

  1. Inspection
  2. Diagnostics
  3. Recommendations for Improvement

What you see, hear, smell, and feel in the home (or taste, but please don't let your client see you) is often the most valuable testing you perform, and it can tell you a lot about what you expect to find in the diagnostic stage. Never use your testing tools until you know what you're looking for (for example, if the A/C isn't running well, discovering that the coils are filthy should NOT lead to superheat and subcooling testing- you should clean the coils first).

The diagnostic tests are what separates a pro from an opinion-giver, and the tragedy is that not only are diagnostics seldom performed in the HVAC field, most HVAC techs are not even supplied with the equipment or training necessary!

Recommendations should only be offered once performance diagnostics have been run, so you and your client can be sure that the solution offered will solve a pinpointed problem.

There are generally always three recommendations you'll make in any home:

  1. Air Sealing
  2. Insulation
  3. HVAC (including anything that heats, cools, or moves air)

Air leakage will defeat any insulation or HVAC improvement you make, so make sure to always start there.  Not only that, but it's cheap, straightforward, never needs maintaining or replacing, and doesn't use energy over the long-term.

Insulation, likewise, is inexpensive and efficient, and must be consistent for the HVAC to function properly.

Lastly, the HVAC itself must be properly sized, selected, and installed, AND THEN VERIFIED WITH PERFORMANCE TESTING. Everyone thinks they do good work- most are woefully mistaken.  The pros who know, know because they tested their work before they left. Those pros don't waste money on callbacks.


As far as the home performance professional is concerned, there are two main systems in any home:

  1. The Envelope (air sealing and insulation)
  2. The HVAC (anything that moves heat or air within the home)

The important thing to remember is that the Envelope will always defeat the HVAC if they're working at cross purposes.


Since we're not talking about energy efficiency, as already mentioned, and we're not talking about sustainability or 'green' stuff, what ARE we talking about? CONTROL.

Control is the goal. If you control all 4 ELEMENTS by using the 3 STEPS to make 3 RECOMMENDATIONS on the 2 SYSTEMS, then you've achieved a high performance home, regardless of what the occupant chooses to do with the space.

And the only way to demonstrate control is with PERFORMANCE TESTING. All building codes across the country will require performance testing (at least of ductwork) by 2017, due to a requirement of the ARRA funding of 2009.

Eventually, homeowners will understand that they can demand a guarantee on any contracting work they pay for, and there will be companies who can continue to profit in that business.  There will also be companies who have never tested their work, and find out that it doesn't pass performance testing- under the immediate pressure of performance-based guarantees, many of those companies will not survive.  Make sure your company does excellent work before your clients ask to see the proof!

Holes in the House: JULY 2015 Building Forensics Mastermind

Corbett Lunsford

In the past month, I've investigated and tested a lot of homes, and made a lot of home improvement recommendations in each of them- it's always hard to boil it down to 30 minutes of material, but here's this month's crazy fast crash course through a few of my favorite jobs that used scientific testing to help homeowners, architects, developers, and contractors get their homes under control!

Every month's series episode is on the First Wednesday at 1pm Central, and it's always totally free!  Sign up now and be reminded at:

PODCAST #63 ALL OVER THIS LAND: Taking the Temperature of Homebuilders Around the World

Corbett Lunsford

Today Corbett takes you on a tour of performance based building from a sampling of builders around the world, and realizes that the millionaires are going to be very angry when they realize what they're paying for isn't nearly as good as the affordable housing to be had on the other side of the tracks. Hosted by Corbett Lunsford at the International Builders Show (IBS) in Las Vegas and the Michigan Habitat for Humanity HOMES Summit, January 2015.

Thanks to Robert & Deb Berger, Hiroshi Kuratsu, Rick Eversold, William Wright, Dustin Johnston, Scott Spencer, Bob Passkey Sr., Joey Cuzano, and Bruce Rumsberg for voicing their opinions about performance testing!

To download this episode or hear more, subscribe in iTunes or visit