Q&A Spotlight

Why Is It So Humid In Here?

Posted on February 16, 2015 by Scott Gibson

From the sound of it, Andy Chappell-Dick has left no stone unturned in his quest to keep the air inside his house comfortably dry.

His extremely tight new house in northern Ohio (Climate Zone 5) is built with structural insulated panels, and heated and cooled with a pair of ductless minisplit heat pumps. For ventilation, Chappell-Dick has a Venmar Kubix heat-recovery ventilator(HRV). Balanced ventilation system in which most of the heat from outgoing exhaust air is transferred to incoming fresh air via an air-to-air heat exchanger; a similar device, an energy-recovery ventilator, also transfers water vapor. HRVs recover 50% to 80% of the heat in exhausted air. In hot climates, the function is reversed so that the cooler inside air reduces the temperature of the incoming hot air. that pulls exhaust air from two small bathrooms and supplies fresh air to two upstairs bedrooms with a flow rate of between 40 and 80 cubic feet per minute (cfm).

Choosing the Right Wall Assembly

Posted on February 2, 2015 by Scott Gibson

Southwest Nebraska sounds like the kind of place that gets all kinds of weather: hot and occasionally humid summers, cold winters, and by many accounts lots of wind. This is where Nicholas C will be building his house, and the question is, how?

He's done so much reading on the subject that he's now confused by the number of options he has. Getting it right is important because Nicholas plans on living in the house for a long time.

His best thinking so far? A 2x8 stud wall framed on 16-inch centers and insulated with blown-in cellulose, then wrapped in 2 inches of rigid foam insulation.

Designing an HVAC System for a Cold Climate

Posted on January 19, 2015 by Scott Gibson

Randy Bunney is building a new house in a challenging environment — north central Minnesota, where overnight temperatures plunge well below zero and heating-degree days over the last three years have averaged more than 8,600 annually.

The high-performance, passive-solar home will be a relatively small 1,100-square feet with two bedrooms, an open living-kitchen-dining area, 1 1/2 baths, a mudroom and a mechanical room. Bunney is planning on exterior walls insulated to R-40, the roof to R-60, and "near airtight" construction.

Choosing a New Wood Stove

Posted on January 5, 2015 by Scott Gibson

Patricia Appelbaum is in the market for a new wood-burning stove, one without a catalytic element, to provide mostly supplemental heat for her 1,600-square-foot home. There are a lot of models to choose from, and that's part of the problem.

How to Heat a Garage

Posted on December 22, 2014 by Scott Gibson

If you're lucky enough to have a garage, you already know it can be used for more than keeping your car out of the snow. As Kent Jeffery explains in a Q&A post at GreenBuildingAdvisor, garages also are useful for car and equipment repairs, and for storing garden vegetables, cans of paint and anything else a spouse may not want in the house.

But in order for a garage to serve those purposes, the temperature has to be above freezing — and for much of the country that means a source of heat.

Second Guessing an Insulation Upgrade

Posted on December 8, 2014 by Scott Gibson

Is there anything worse than getting midway through a renovation and then suddenly wondering whether you've got some important detail all wrong?

That seems to be the predicament of William Lucrisia, who's in the midst of an insulation upgrade at his house north of Seattle.

"The house was heated by propane," he explains in a Q&A post at Green Building Advisor. It was a cost that was hard to get hold of, especially with some of the design [features] of the house (high ceiling)."

Does a Crawl Space Make Sense?

Posted on November 24, 2014 by Scott Gibson

Michael Geoghegan is designing a house for a mixed, humid climate and he plans on using an insulated crawl space.

An Energy Upgrade On a Budget

Posted on November 10, 2014 by Scott Gibson

Christian Rodriguez has taken an important first step in improving the energy efficiency and comfort of his 1880s home by arranging for an energy auditEnergy audit that also includes inspections and tests to assess moisture flow, combustion safety, thermal comfort, indoor air quality, and durability.. With the results in hand, his first step was to air-seal the attic and add 20 inches of cellulose insulationThermal insulation made from recycled newspaper or other wastepaper; often treated with borates for fire and insect protection..

"This made quite a difference both in comfort and heating bills," he writes in a Q&A post at Green Building Advisor. Now comes a difficult decision: what to do next.

Determining the Best Attic Option

Posted on October 20, 2014 by Scott Gibson

Attics come in many shapes and sizes, but they are either conditioned or unconditioned. That is, they are insulated and heated like the rest of the house and can be considered conditioned spaceInsulated, air-sealed part of a building that is actively heated and/or cooled for occupant comfort. , or they are designed to allow the free circulation of outdoor air and become unconditioned spaces.

Is one option better than the other? That's what Rus Pearson would like to know.

Passivhaus Design in Minnesota

Posted on October 6, 2014 by Scott Gibson

As net-zero energyProducing as much energy on an annual basis as one consumes on site, usually with renewable energy sources such as photovoltaics or small-scale wind turbines. and PassivhausA residential building construction standard requiring very low levels of air leakage, very high levels of insulation, and windows with a very low U-factor. Developed in the early 1990s by Bo Adamson and Wolfgang Feist, the standard is now promoted by the Passivhaus Institut in Darmstadt, Germany. To meet the standard, a home must have an infiltration rate no greater than 0.60 AC/H @ 50 pascals, a maximum annual heating energy use of 15 kWh per square meter (4,755 Btu per square foot), a maximum annual cooling energy use of 15 kWh per square meter (1.39 kWh per square foot), and maximum source energy use for all purposes of 120 kWh per square meter (11.1 kWh per square foot). The standard recommends, but does not require, a maximum design heating load of 10 W per square meter and windows with a maximum U-factor of 0.14. The Passivhaus standard was developed for buildings in central and northern Europe; efforts are underway to clarify the best techniques to achieve the standard for buildings in hot climates.-certified houses become more commonplace, it's not at all unusual to hear of exterior walls rated at R-40 or R-50. But that's not going to be nearly good enough for Tom Schmidt, who's building a 3,800-square-foot house in Minnesota.

R-80 is more like it, and the walls need to be "cost-effective" as well as not too thick.

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