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5928 N Paulina St
Chicago, IL, 60660
United States


Quality control for home improvement and new home building, plus building forensics for solving virtually any home performance problems. Nothing can hide from advanced diagnostics in residential construction, and you should never have to guess or assume that home improvements worked- proof is possible. Ask for it.

Videos, Podcasts, & Articles

Home performance articles and stories from the field with internationally respected building forensics gurus 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!

Engineering a TOURING Tiny House: See the Full Series

Corbett Lunsford

Grace and Corbett are building a performance-proven tiny house on wheels called the Tiny Lab! It's going to be built from November to February, and it starts a 16-city US Tour in March of 2016. Here's the full series of four webinars from August 2015 detailing the engineering of a super cool tiny house on wheels!

In #1: SHAPE AND LAYOUT, Corbett and Grace show the 3D sketchup model of the Tiny Lab, and bring engineer John Bergman in for some heavy lifting to do with pinpointing the center of gravity on this 24 ft trailer tiny house.

In #2: AIRSEALING, INSULATION, & WEATHER BARRIERS, tour the process of energy modeling the tiny house to determine the optimal R-values and level of airtightness, and hear about vapor barriers, moisture control, and drainage.

In #3: HEATING, COOLING, AND VENTILATION, you get a taste for how wrong a lot of the discussion goes about homes in general, and tiny homes especially. The HVAC design, including Manual J heat load calculations and hourly solar gain curves are analyzed and used for things as straightforward as deciding which direction to park the tiny house.

In #4: BELLS & WHISTLES, see behind the design of the solar PV kit, formaldehyde-free plywood built-ins, composting toilet, off-grid plumbing challenges, and luxury items that just add that quality of life that tiny house occupants are seeking.

We really hope you'll tune in for the videos of construction- you can subscribe to our YouTube channel right now with one click!

PODCAST #74 SAFE, HEALTHY, AND TESTED: BPI's Larry Zarker means home performance, not VD

Corbett Lunsford

Today Corbett talks at the Habitat X thinktank with BPI CEO Larry Zarker about his passions: helping contractors, building homes that stop sending you to the emergency room, and how to infiltrate the health insurance industry to help make all that happen. Sponsored by the 6-week Fall Fast Track distance mastermind course for home performance black belts.

To download this episode or hear others, visit

Engineering a TOURING Tiny House: HVAC

Corbett Lunsford

Tiny home performance is made even more perfect in our third presentation in this tiny house engineering series! Watch as I walk you through the design and engineering of the heating, cooling, dehumidification, bath and kitchen exhaust, fresh air ventilation, and water heating systems in the Tiny Lab.
If you stay tuned to the end, you get to hear me realize I'm a total idiot! Fun stuff!

How to Test a Kitchen Exhaust Hood

Corbett Lunsford

Let's do building diagnostics! Watch me demonstrate the commissioning of a kitchen exhaust fan in a big new apartment building. Just because the label says it sucks air doesn't make it so. Proof Is Possible- ask for it. Using a Testo 417 large vane anemometer.

Mystery #1: Solve the Air Conditioner Problem!

Corbett Lunsford

Welcome to the new series where you solve it yourself! Watch me demonstrate a common problem happening in a brand new home- will you be able to diagnose the problem and prescribe the solution?  In heating and cooling, airflows and pressures are the most critical and least understood factors for performance.

Engineering a TOURING Tiny House: Airsealing, Insulation, Weather Barriers

Corbett Lunsford

Grace and Corbett Lunsford walk through the process of engineering their Tiny Lab, a tiny house taking them on the Proof Is Possible US Tour! Tonight's episode is on designing the barriers to heat bleed, air leakage, and water leakage.
WORKING TINY LAB SPECS: Floor 2x6 with R-21 EcoBatt insulation. Walls 2x4 with R-15 EcoBatt insulation. Ceiling 2x6 with R-21 EcoBatt insulation. Air leakage down to 2 ACH50 or less.

I struggle with frustration, and you might be able to hear it in this presentation.  I'm frustrated that as a relative newbie in the homebuilding industry, I'm constantly seeing work done thoughtlessly, or at least with not as much thought as work deserves. Sorry if I come across as an a-hole, I promise I'm not- I just care a whole heck of a lot, and I spend all day in buildings where my caring comes back to haunt me.

PODCAST #73: Drying Air vs. Drying Stuff

Corbett Lunsford

Today Corbett is psyched to again talk with Lew Harriman, the master of dehumidification and author of lots of books on moisture control, about guess what! Lew takes us on a tour of macro-drying philosophy, down to the nitty gritty of ERVs and hairdryers and wet spots on your carpet. Sponsored by Corbett's Fall Fast Track 6-week mastermind course in free market home performance.

To download this episode or hear others, check the show out on iTunes or at

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,

Engineering a TOURING Tiny House: SHAPE & LAYOUT

Corbett Lunsford

In our first reveal of the Tiny Lab, Grace and I show off the structural and stress engineering basics of a tiny house, assisted by actual engineer John Bergman.


We believe showing home performance dynamics through the lens of a tiny house tour will make it click for a lot of American homeowners. That's why we've created the Proof Is Possible Tour, and we'll visit 16 US cities in 2016! 

What Clients Want: AUGUST 2015 Building Forensics Mastermind

Corbett Lunsford

First, let me make the world a better place by saying this: DO NOT BUY AN ATTIC FAN. ESPECIALLY A SOLAR POWERED ONE.  Fans that suck air out of the attic through the roof (not whole house fans) are COMPLETELY THE WRONG THING to fix the problem you're having. No matter what the problem is, it's definitely the wrong thing to use. Now, enjoy learning why!

First Wednesday of every month, I demonstrate all the advanced testing used for last month's awesome clients. I actually re-worked this entire webinar the night before because of a job that day that knocked my freaking socks off- solving a chimney backdrafting problem with some super sucky solar attic fans! A few other jobs are sprinkled in, to add spice.


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!

Tiny House Engineering Webinars in August!

Corbett Lunsford

In 2016, the Proof Is Possible Tour will visit 16 U.S. cities, and we'll be training homeowners to understand measured home performance so they can truly OWN their homes. And our ride: a touring tiny house on wheels!

Over the next 4 weeks, Grace and I will show you the performance design of the Tiny Lab, a performance-proven design. Learn how the engineering of a tiny house gets done, and understand the performance of homes big or small through this tiny example!


WEEK 1: Engineering the Shape & Layout
WEEK 2: Engineering the Insulation, Airseal, & Weather Barriers
WEEK 3: Engineering the HVAC
WEEK 4: Engineering the Bells & Whistles