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Energy Vanguard Blog

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Does the Nest Learning Thermostat Save Energy?

 
nest learning thermostat energy savings

The Nest Learning Thermostat has been on the market for nearly four years now. One of the biggest things the Nest folks use as a selling point is energy savings. "Programs itself. Then pays for itself." That's the first thing you see when you go to the Nest homepage. But what do the data say? Three independent studies plus a whitepaper from Nest provide some answers.

This Lack of Building Enclosure Design Makes Extra Work

 
air leakage infiltration building enclosure design garage ceiling

Take a look at the photo below. See anything missing? If you don't see it yet, look at the big opening at the bottom right of the photo and you should be able to deduce what that room is. It's a garage. Now look at the framed wall between the garage and where I was standing when I took the picture. You see it, right?

Nest Thermostat Data Unveiled at ACI Conference

 
Nest thermostat

The Nest thermostat has been around since October 2011, quietly collecting data on how your home — and the homes of hundreds of thousands of your neighbors — operates. It gathers information about indoor temperature, relative humidity, air conditioner runtime, auxiliary heat operation for heat pumps, and much more. Unlike the Ecobee thermostat, however, Nest doesn't let its owners see all those data (which is a problem only for energy geeks really). Enter Michael Blasnik.

Why Did the Chicken Go to the ACI Conference?

 
aci national home performance conference chicken after dark 2015

I love the ACI National Home Performance Conference! This year's conference was spectacular. It was in New Orleans, which is always fun. The stars of home performance were there. The Californians came back. (That's one of them in the chicken costume below. ACI after dark, which even has its own Twitter handle, @ACIafterdark, is fun no matter where the conference is, but wild things can happen in NOLA.) And perhaps best of all, Michael Blasnik revealed data from the Nest thermostat for the first time.

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Moisture Transport, Sorption Isotherms, and Aliens Drinking Beer

 
water damage in OSB sheathing

You know about the fourth state of water. (You read my last article, Introduction to the Physics of Water in Porous Materials, right?) Not liquid, not vapor, and not solid, it has properties similar to liquid water but not quite the same. Today we'll take a look at how that physics affects the transport of water through porous materials.

Introduction to the Physics of Water in Porous Materials

 
water intrusion capillary action wicking

I like to tell people I'm a recovering academic. The truth is, though, that I haven't left physics behind. That would be impossible since I've been making a career in the world of building science. So, today I'm going to delve into that subset of building science called building physics as we take a look at the physics of water in porous materials. You'll also learn about the fourth state of water, the one that's not liquid, not solid, and not vapor.

Joe Lstiburek's Ideal Double-Stud Wall Design

 
double stud wall design Joseph Lstiburek BSC 550

Joe Lstiburek called me last week to set the record straight. I had written an article about a study of moisture in double-stud walls in a Massachusetts home, and his company, Building Science Corporation (BSC), had done the research as part of the Building America program. They found elevated moisture content in the cold, exterior sheathing, and Joe wanted to make sure everyone knew, "I would never build that wall because I consider it too risky."

My Passion for Building Science Education and Bad Contractors

 
Installing windows before house wrap is like tucking your raincoat into your pants.

When asked to name our passions at the conference I went to in Portland, Oregon last week, I had to think about it a little bit. I had just been discussing what it is we aim to do at a company strategy session a few days before, so that discussion came to mind. At the strategy session, I said we provide building science information to help people who want to do things the right way or who want to hire contractors who do things the right way. I knew there had to be a better way to say it, though.

Is This the End of the Double-Wall, Cold Sheathing Scare?

 
double wall cold sheathing moisture content BSC 1

Insulation is good. More insulation is better (although at some point, more may not be cost effective). It reduces the amount of heat a home loses in winter or gains in summer. You can get there by building thicker walls and putting more insulation in the cavities, or you can put insulation on the outside of the structure, as in the Perfect Wall. The photo below shows thick insulation in the cavities of a home with double-wall construction.

An Interview with Terry Brennan — a Building Science Pioneer

 
terry brennan abaa conference dallas 2015

Last week I got a chance to sit down and talk with Terry Brennan in Dallas at the Air Barrier Association of America’s annual conference. He may not be as famous as Joe Lstiburek, but he’s every bit the building science pioneer. Armed with a physics degree, the ASHRAE Handbook of Fundamentals, and a desire to reduce the environmental impact of buildings, he built houses and wrote energy modeling computer programs back in the 1970s and ‘80s. When he finally met Lstiburek in the early ‘80s, he learned not to bet against Joe’s ability to do ridiculous things. Read the transcript of our conversation and find out what that bet was and more.

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