Back in my home performance contracting days (2004 to 2007), I spent a lot of time in unconditioned attics and crawl spaces. First, I was there to find problems. Then, if the homeowners hired me, I'd go in and do…
It's time to revisit one of my favorite topics: the powered attic ventilator. Ten years ago I wrote an article titled Don’t Let Your Attic Suck - Powered Attic Ventilators Are a Bad Idea. It's got 169 comments and would…
Poor installation of insulation matters. Even in cases where you might think the R-value won't be affected, it is. Eleven years ago this month, I wrote an article about one of the most important and misunderstood principles in building science. …
A lot of people have gotten the message that ducts for your HVAC system—and the system itself—should be in conditioned space. Researchers at the National Renewable Energy Lab (NREL) studied the effect of ducts in an unconditioned attic and found…
Sizing a heating or cooling system should start with an assessment of the heating or cooling load. Nowadays, we know the physics behind heat transfer, so we can come up with fairly accurate predictions of how much heating and cooling…
Using the wisdom of Cool Hand Luke to explain building enclosures, mechanical systems, or indoor air quality is a long established tradition in building science. Joe Lstiburek's Cool Hand Luke Meets Attics is the pinnacle of this genre, of course,…
Yesterday I did a consultation with a homeowner in Michigan. He's got a 60 year old house with a boiler and radiant heating system that has become a burden. The pipes for hydronic distribution system just developed their seventh leak…
Ten years ago, Georgia led the United States in adopting a new energy code. Perhaps the biggest advance was that it required all new homes to meet a threshold for airtightness (7 ACH50). Now most states require blower door tests…
![Design Temperature And Degree Days Are Different [Photo By NOAA ESRL, From Flickr.com]](https://www.energyvanguard.com/wp-content/uploads/2021/02/thermometer-cold-design-temperature.jpg)
People new to building science and HVAC are confronted with a lot of terms for things that are related but different. Load and capacity. Energy recovery ventilator (ERV) and heat recovery ventilator (HRV). Hot water heater and cold water heater. …
Sometimes companies that make products stretch the truth, embellish features, or rely on their potential customers' ignorance of how things work. Shocking, I know. The world of electric heating has such companies. But if you're looking for a device that…