A Cold Climate Construction and Energy Blog
This blog post first appeared in two issues of Fine HomeBuilding Magazine: Issues 321 and 322. Part of a series that included 17 short articles written by 7 different authors. My first contribution appeared in the letters and reader feedback section of the February/March issue, titled “The biggest mistake of all?” You can read that post here.
Continue reading “Common Building Science Mistakes to Avoid”
This post first appeared on the Green Building Advisor website.
How do you define comfort inside your home? Thermal comfort is the big one, not being too hot or too cold. Thermal comfort is one of the most important questions I ask during building investigations and energy audits. Having the right indoor humidity is another, not too damp and not too dry, which can affect not only comfort, but also human health and the durability of the structure. How about the visual aspect of comfort, it’s always nice to be in a room that “feels good” simply because of the way it was designed or how it is furnished. This discussion on comfort though is going to be on sound, the noises you experience inside the home and how noise pollution can affect comfort.
Continue reading “Construction Design-What Is and How to Achieve Acoustical Comfort”
I’m going to make a statement that not everyone will agree with, windows leak water. Not all are leaking now, some will develop the leak later, as the window and the sealing products used to install the window age. The leak may be an error or failure in the installation, or it could be the window itself that is leaking. It could be a design error, water funneling off a roof over a window, such as in the photo. The leak may only be an incidental amount of water, or it could be a major bulk water concern. The leak may also only be active during the once every ten-year major rain fall event. The point is windows will leak water.
Insulation and R-value go together like hard work and sweat. R-value is, of course, the resistance to heat flow. We’ve been taught to think more is better, which is true to a point. I’m changing the insulation in the wall of my home from R-7, originally installed in 1952, to R-15, and I’m excited to see how much more comfortable my home becomes. There is an argument that at a certain level, more insulation will cost dollars to save pennies. At what point do we reach diminishing returns?
As I write this blog, a good portion of the nation is experiencing very cold temperatures with high winds. I’m currently sitting at -9°F with a windchill or feels like temp of -38°F. Chatting with a good friend in Kansas City recently, he was impressed by the below zero temperature readings. (He was actually begging me to stop sharing and keep the nasty weather in Minnesota.) Because of the weather, I’ve been receiving emails and DMs on Instagram about how people’s houses are reacting to this weather extreme. Window condensation has been one of the more frequently asked questions, so I figured I’d cover that topic in a blog post.
This blog first appeared on the Green Building Advisor website.
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:
ACH50/n-Factor = ACHnat Continue reading “Building Science-Natural Air Leakage”
This post originally appeared on the Green Building Advisor Website.
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?
Continue reading “Building Science-Tight Homes and Negative Pressures, When Should We Be Worried?”
This post originally appeared on the Green Building Advisor website. www.greenbuildingadvisor.com
Pyrolysis [pahy-rol-uh-sis] noun
The chemical decomposition of wood by the application of heat alone in the absence of oxygen.
I used to perform risk assessment inspections for a couple small, local mutual insurance companies. These companies would insure properties that were considered “high risk”, most were rural, some were accessible only by boat, ATV or snowmobile and they were often a long way from the nearest fire department. Many had solid fuel burning appliances, usually a woodstove or fireplace. Part of my job was to make sure that the woodstove or fireplace had the proper clearances to combustibles, proper floor protection, and that the stovepipe and chimney systems met the requirements of the manufacturer and/or code. Most installations were safe, but every once in a while, I would find a home in danger of burning down. Continue reading “Building Science-Pyrolysis”
This year seems to be a good (or bad depending on how you look at it) year for ice dam problems in my area, the intensity of ice dams seems to change year to year. I was recently on an ice dam diagnostic with an insulating contractor and a general contractor, the home was built in the early 1990’s and there is evidence there have been issues from the beginning. We spent a couple hours testing this home, I’ll get into what we found in a bit.
This three-part series first appeared on the Green Building Advisor website and has been condensed into one post.
An unconditioned and uninsulated crawlspace, an unsealed and uninsulated forced air heating system, and an uncovered dirt floor, which by the way has a sewage leak. If this were your home and you wanted to make improvements, where would you start? Continue reading “Building Science-Existing Construction Improvements”