fBy combining an “always on” ERV and quiet bath fan this installation achieved above-and-beyond air quality.

One of the challenges with small “mother-in-law” apartments and accessory dwelling units (ADUs) is that they’re often built without adequate ventilation, or unbalanced systems that create drafts or fail to clear the air, or worse, haul other pollutants back into the building.

Green Builder's Annual Building Science Ebook is free to view online or as a pdf download.

From the editors of Green Builder magazine comes a concise look at the latest, greatest innovations changing how homes and multifamily projects are built. From weather barriers to SIPs, utility programs to whole-house air purification that can address urban smog, we look at the how and why of building today.

This question came up in our recent webinar on Building Science, from listeners concerned about the impacts of various filter media on airflow through ducted systems.

Q: Ive heard that certain air filters cause airflow restriction and damage to HVAC equipment.  I read that if the face area of a filter medium is larger, and an ECM motor is used, the flow reduction is less significant.

New tools and battery systems bring the off-grid solar jobsite a step closer. 

When Ryobi unveiled its new 18V One+ 10-Inch Miter Saw, the time seemed right to test the viability of an all-solar-powered jobsite. I already owned a number of the Ryobi tools that use the same battery, along with a Ryobi P131 in-vehicle charger (a must), so I had them round out the suite for me with the miter saw, a P5231 orbital jig saw, a five-inch random orbit sander P411—and a plug-in, six-port battery supercharger.

My friend Oscar van Loveren is a well-informed solar dabbler and airline pilot. He walked me through the basic mathematics of watts, amps and capacity when it comes to solar charging. He agreed that 200 watts of photovoltaic should be enough to bring a 100-amp, 12-volt battery up to charge over the course of a sunny day.

At the heart of Mandalay Homes' "disruptive" innovation is a new product that seals the smallest leaks, greatly reducing air infiltration.

At a popular living history center in Southern England, historians have put together a collection of the typical tool collection used by a home framer in the 17th to 19th Centuries.

If you're a builder, most these tools are probably familiar. Researchers at the Weald and Downland living history museum in Chichester, UK, collected these tools to illustrate how traditional rural homes were built. No circular saws, no chop saws, no table saws or power drills.

Field tests show that the unrestricted airflow is more important than shade.

YOU CAN'T BLAME PEOPLE for thinking it might be a good idea to shield outdoor air conditioner compressors from the blazing heat of the sun. It's an important consideration, because more than ever, compressors for electrical mini-splits are being installed on the roof, where they are exposed to full sun all day long, often sitting just above a black, roasting EPDM roof covering.

To prevent cracks, and head off mold and rot in finished basements, a sturdy vapor barrier is still the most important detail.

Creating the “perfect” slab has always been a challenge for homebuilders. Even when built to code, slabs sometimes crack and fail. What went wrong? Often, sloppy installation is the issue. Seams in the underlayment are not sealed and overlapped properly, or workers punch holes in the plastic--or it simply doesn’t extend fully underneath the slab and vertically up the edge of the buried part of the slab perimeter.

Getting to net zero is within easy reach with new technologies. The only real hurdles are politics and ignorance.

A FEW MONTHS AGO, I spoke to builder Gene Myers of Thrive Home Builders in Denver about whether mini-split heat pumps could be powered by solar PV panels, essentially converting electricity into affordable, clean heating and cooling for homes.

“We’re doing that on all of our new homes,” Myers told me. “We have been for a couple years now.”

That took me by surprise.

Now considered a waste byproduct in some parts of the world, wool insulation is an idea that is getting some traction in the U.S.

A few years ago, I toured Ireland on a journalistic junket intended to promote the island nation's innovative building technologies. The Irish have had a rough ride, after their "Celtic Tiger" economic boom crashed and businesses fled. On that trip, I visited a company trying to sell wool insulation. The raw wool, they explained, cost them almost nothing, because it's now consider a waste product from what has become a livestock-for-meat industry. Wool insulation is a great concept, with the primary cost of production being the cleaning of the fibers, which tend to need a serious scrubbing.