When conducting a blower door test, one of the ways we express the findings is with air changes per hour at 50 Pascals (ACH50). As an example, a new home is blower door tested and found to be 2.75 ACH50, this means the entire volume of air inside the home is exchanging with the outside air 2.75 time per hour at the test pressure of 50 Pascals. When discussing blower door testing with builders and homeowners, it can be hard for them to relate to the ACH50 number other than they know the home needs to be less than a certain level of air tightness to meet current code requirements. Expressing the tightness as natural air leakage can sometimes be helpful. How can we calculate the natural air change rate? Well, there’s a formula:
I recently made the 1349-mile trip from my home in Northern Minnesota to Austin, Texas. Stepping off the plane in Austin at 9:30 in the evening on November 8th, my first impression was it was hot, hot and muggy. Much different than the 35°F when I left Minnesota. I was taking my first trip to Texas to attend the Texas Building Science Symposium. A two-day event of nothing but building science education.
The Texas Building Science Symposium is an off shoot of the Midwest Building Science Symposium started by the Kansas City chapter BS and Beer group. Travis Brungardt and Joe Cook started the symposium in 2020, which I had the pleasure of attending. That first event had two speakers, Steven Baczek and Jake Bruton. In 2021, the event grew to include more speakers. This year, the symposium was held not only in Kansas City, but also in Chattanooga, Tennessee, Austin, Texas, and an upcoming event in Washington, DC. Continue reading “Construction Education-Texas Building Science Symposium”
Thermal imaging tools used to be so expensive, the only people to own them were researchers and specialty tradespeople. That’s not the case anymore. Anyone can get a decent thermal imaging camera for under a $1000, my latest camera is a good example.
I was introduced to Hikmicro at the most recent International Builders Show, a newer manufacturer to the industry, Hikmicro had several of their products on display where interested people could try them out on the show floor. I gravitated towards the Pocket Series of cameras. This style of camera looks closer to the traditional digital camera, or a smart phone than the pistol grip thermal imagers we are used to seeing. Compact but filled with features, the Pocket 2 I purchased has the resolution of a more expensive camera (256×192). By comparison, my first thermal imaging camera had a resolution of 60×60, and the Pocket 2 is one-third the price of that camera. Continue reading “Diagnostic Tools-Hikmicro Pocket 2 Thermal Imaging Camera”
A home’s electricity use is affected by many factors. The efficiency of the home, the type of equipment in the home and the habits of the occupants all play a role. Up until recently, monitoring electricity use took complicated equipment. That’s all changing. New technology allows for monitoring whole electrical panels or individual circuits through technology included the electrical panel or the overcurrent device (breaker). Other technologies that have been around a while are aftermarket products that can be installed inside panels. There are also options that include point of use metering or utility usage monitoring performed directly though the utility meter. These electrical monitoring options can be installed in both new and existing construction. Continue reading “Diagnostic Tools-Monitoring Electricity Usage”
I saw this video several years ago when I first leaned of Corbett Lunsford. Shortly after, I purchased his book, Home Performance Diagnostics, a book on different testing methods for evaluating a home’s performance. You can check out Corbett’s YouTube channel here, (1171) Home Performance – YouTube
The video struck a nerve with me, there are so many rural homes built in my area that have no inspections or performance testing conducted, they really are like the video. If you are a homeowner, ask the contractor for performance testing, and if you are a contractor, find someone in your area to partner with, they may help to make you a better builder.
A couple years ago I was asked to perform a blower door test on a new home. The home was small with a footprint of only 1130 square feet. When the test was completed, the test report indicated an air leakage rate of 91 CFM at the test pressure of 50 Pascals, .33 ACH50. Completely unexpected for this code-built house. (I actually measured the volume of the home again and ran the test two more times before I was convinced I had an accurate test.) The contractor contacted me some time later and indicated the homeowners were noticing air coming through the exterior light switches when the dryer was operating. The dryer was producing close to the same negative pressure as my blower door every time it was being used, a negative pressure of about 50 Pascals. Is this a problem?
The main purpose of a blower door test is to confirm the integrity and continuity of the air control layer or air barrier. I have a few different options on how to perform a test. Which option I choose is dependent on the reason I am performing the test.
This post is the unedited version of an article I wrote for Fine HomeBuilding magazine which appeared in the December 2021/January 2022 issue. My original version was more focused on garage designs for heating dominated climates, FHB helped to make the article relatable to other climates. The link will bring you to the printed version. FHB304-ConditioninganAttachedGarage.pdf (finehomebuilding.com)
I consider the attached, heated garage a luxury item. I used to have one, it was nice not having to scrape ice or clean snow off my vehicles. Having a warm car when its below zero outside was also nice. But I was paying for that luxury, around $100 per month for energy costs in December, January, and February. There was also the added cost of the heating equipment and extra insulation needed when building the space. And lastly, there was always moisture in the space, both in liquid and vapor that needed to be dealt with.
I’m about to start a remodel project of the family room in my home. Not your normal fresh paint and new floor covering update, but a complete gut down to the stud renovation. New electrical, new drywall and no more popcorn ceiling. I’m curious as to what my effective R-value of the exterior walls will be when I’m done with the space. This includes the windows. I figured I’d share my calculations with you. This post is math heavy, if you’d like to skip the math, read the final five paragraphs.
Walk through any modern construction project and you’re bound to see construction tape somewhere on the site. Whether it’s taping the seams of a mechanically attached water resistive barrier (WRB), flashing a window or door opening, or making sure an air barrier is continuous, tapes have become a key part of many assemblies. Mostly, we use tapes for two purposes, to keep something in, like the air we pay to condition, or keep something out, like water. It’s important to use the right product for the right application.