How to Fix Summertime Heat on Your Top Floor

Hi Corbett-
Finally, I have two solid quotes for air sealing. I have one new concern, however. My finished attic gets really hot in summer, and the A/C dedicated to this attic rarely is able to cool the space below 82 degrees.  From what I have read, besides implementing some kind of reflective roofing material, the only way to keep an attic cool is plenty of airflow.  So, if we air seal the attic and add insulation (which I have read holds and radiates heat in summer ?), is this air sealing initiative going to make my attic unlivable in the summer?
Thanks!
R.L.

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Hey there R-
First thing to do is stop thinking about your top floor as an attic of any type.  Yes, it used to be an attic, but now it's supposed to be inside the enclosure, so let's call it what it is- your valuable living space.
Not only will airsealing NOT going to make your top floor (finished attic) hotter in summer, it is in fact the ONLY THING that will make it cooler up there.  What's happening is called reverse stack effect: your air conditioners are creating cooler, drier, DENSER air, which sinks to the bottom of the house. All the air conditioning wants to be in the bottom of the house at the same time, so it creates a higher pressure down there, and there's a low pressure at the top of the house.
The cool, heavy air escapes through gaps and cracks in the bottom of the house, and the house now needs air, so it breathes in at the most depressurized (and also hottest) place- at the very top.  So all the air that's in your top floor rooms is coming from the attic spaces and the roof cavity.
Lastly, it's a total myth that attic ventilation will keep an attic cool- #1, attic ventilation is actually for venting MOISTURE, not heat; and #2, you don't actually care how hot it gets in your attic, since it's not part of your house.  The roofing manufacturers used to void their warranties if the attic got too hot, but they don't do that anymore.  You're free!
For a more detailed look at attic airsealing, watch this:

How to Master the Multi-family Blower Door Test

Hello Corbett,
A need to run a Blower Door test at a 3 house complex here in Greece. The houses are in the row, this means that normally I should have three Blower door devices, in order to measure the house in the middle. But I have only one Blower Door!
Additionally, I will need to hand over a written document (report), in order to certify the construction to the Passive House Institute. Do you have any suggestions?
Best and thanks in advance,
Stefanos

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Hey Stefanos-
Great question! You do not, in fact, need multiple blower doors, because you actually want to include the unit-to-unit air leakage.  The measurement of all uncontrolled air leakage to outdoors and to other townhouses is a valuable one, and it should be the goal especially when building to Passive House (or PassivHaus) standards.  Watch this video for a visual explanation:

How Should a Homeowner Shop for a High Performance Home?!?

Hello Corbett,
I have been listening to your podcast and heard your request for ideas. You often mention the challenges in educating consumers, and I think my questions might be interesting to the non-professionals in your audience.
I just moved to Denver, Colorado and am considering purchasing a home for the first time. As a potential first-time homebuyer interested in air quality, moisture management, energy efficiency, and building durability, I expect that it is unlikely that I will be able to find a high-performing home at an entry-level price. With the expectation that I may need to invest in some retrofitting, I have a couple of general building performance questions:

Ascertaining current performance

Assuming that a first-time buyer probably will not have access to the sophisticated diagnostics described on your podcast during their search, what are some key things to look for that would indicate a high or low performance?
Utility bills can shed some light on energy efficiency, but how can someone gauge issues like air quality or moisture control?

Performance improvement opportunities

What factors influence a residential building’s suitability for a high-performance retrofit?
Are there factors that would influence the ROI of a retrofit for a modest home? And how could a homebuyer identify those?

Assembling a team

Do you have suggestions about how to assemble your team (realtors, inspectors, and appraisers) to help identify an entry-level home based on current or future potential?
What skills or expertise would you consider important?
Your podcasts have covered issues about financing for retrofits – so there may be nothing new to address here.
 
Basically, it would be great to be able to use a home performance lens during a home search to identify a property in which it is not too difficult or expensive to improve from decent to good performance.
As a potential consumer, I have enjoyed and learned a lot from your podcast. Thank you for thoughts.

Best,
B

Home Performance Pros: Listen, Smile, and Remember Sometimes You're an Idiot

Listening, smiling, and validating are all skills that any home performance professional must have in order to serve homeowners, architects, developers, and other contractors!  Don't get so full of scientific diagnostic proof that you forget we all have to relate to each other in order to make any home improvements or performance-based building project work.

What Spillage Looks Like from a Water Heater

Testing for "spillage" of combustion gases means making sure the bad stuff that's supposed to go UP the chimney doesn't come back DOWN.  It's a critical part of home performance analysis, according to BPI, RESNET, and everyone else.  If you don't know what it looks like, you might feel a little lost- let your old pal Corbett the diagnostics guy show you the single most awesome example of what you shouldn't see in your clients' homes!

I Turned My A/C Off All Day at 106 Degrees

Dear Corbett:

I thought I would send this your way.  I live in the Central Valley of California.  Yesterday it reached 106 degrees.  I did an experiment with my house.  My 1,883 sq./ft. house had a deep energy upgrade over three years ago.  The heating and cooling unit is a 2 stage/2 ton heat pump with no back-up heat.  The second stage of cooling is disconnected so I am cooling with 1.4 tons.  That is one ton for every 1,345 sq./ft.

Yesterday morning I left the house at 7:40 am.  It was 75 degrees in the house and 75 degrees outside.  I closed all of the blinds, turned the HRV off and turned the Heat Pump off.  In other words, I let the house float.  It got up to 106 degrees in Stockton yesterday.  Luci my bride got home at 5:40 in the afternoon and the house was 78 degrees.  She turned the thermostat back on and it brought the temp back to 75 in 30 minutes.

This stuff really works.
Keep up the GREAT work;
Dick Rome

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Dear Dick-

You are awesome. I'm not sure I know many other home performance experts who have fixed their own homes- most of our families have to suffer at home while we help other people get comfortable. Thanks so much for sharing the good word!

~Corbett

PODCAST #75 REALTORS OF THE FUTURE: Chad Curry on Technology & Real Estate

Today Corbett talks with Chad Curry, managing director of the Center for REALTOR Technology, about how performance metrics are changing the real estate industry. From the Internet of Things to measuring air quality in neighborhoods, Chad's group is on the cutting edge of helping the National Association of REALTORS (NAR) incorporate home performance into the selling and buying of homes everywhere! Sponsored by Fall Fast Track- my 6-week mastermind course in home performance ninja techniques.

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

Field Check a Flow Hood Using a Duct Leakage Test Fan

Learn to quickly and easily check the accuracy of a flow hood (in this case, a TSI AccuBalance) using a duct tightness testing fan (in this case, a Retrotec DucTester 200). If your diagnostic equipment isn't giving you accurate readings, no amount of experience will save you!

This is NOT a Roof Leak: What Condensation Can Do

Visit an attic (vicariously) with building performance expert Corbett Lunsford to find a tiny problem that may force us to replace the floor and ceiling of this building- and it might happen to you someday too! Stop guessing- Proof Is Possible. Get up in that attic and have a look!

How Much More Will a High Performance Home Cost?

The answer to this bass-ackwards question is: NEGATIVE DOLLARS AND ZERO CENTS. It costs LESS to build a high performance home, whether that means ENERGY STAR Home, a Passive House, a Zero-Energy Ready home, or any of a number of other green home certifications.  Here's why:

In his first Fall Fast Track week of 2015, home performance guru Corbett Lunsford answers the question "how much more will it cost to build my next home high performance?" The answer to the question is as straightforward as the question is ridiculous!

SEPT 2015 Building Forensics Mastermind Series

Building forensics work shown in detail! Watch as I give a tour of a few of the diagnostics projects we worked on in the past month, especially a battle between two flow hoods that are both past due for calibration, duct tightness testing failures and what to do, and when performance testing professionals should get paid for their work.

Engineering a TOURING Tiny House: See the Full Series

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. The Crowd Sourcing Campaign is happening NOW on RocketHub- CLICK HERE TO PARTICIPATE IN THE TOUR! 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!