mechanical ventilation

Spray Foam Insulated Homes Need Ventilation

Posted on May 03,2015 by ab3 in air sealing

Most installations of spray foam insulation, when properly installed, act as an air barrier. When you use it instead of the fluffy stuff (fiberglass, cellulose, cotton), a house will be more airtight. That's good.

When a house is airtight, the nasties in the indoor air tend to stick around. Volatile organic compounds (VOCs), water vapor, odors, radon, and other stuff you don't want to immerse yourself in make the home's indoor air quality worse.

Another Report on the Great Ventilation Rate Debate

Posted on May 03,2015 by Nate_Adams in ACI

Here is my rundown of the recent Affordable Comfort (ACI) conference in Detroit. It was great to catch up with — or at least brush by — longtime industry friends, in the case of Allison Bailes of Energy Vanguard and Andy Frank of Sealed. It’s really cool that the industry is small enough you can become friends with even the big names.

An Interview with Dr. Iain Walker on Ventilation

Posted on May 03,2015 by ab3 in ASHRAE 62.2

The debate over how much to ventilate a home has been going on a long time. Last year, Building Science Corporation introduced its own standard to compete against ASHRAE 62.2 because (according to Dr. Joseph Lstiburek) of problems that weren't adequately addressed in the ASHRAE standard. I've written about the standard and interviewed Lstiburek and ASHRAE 62.2 committee chair Paul Francisco. (See links at bottom.)

Exhaust-Only Ventilation Systems and Radon

Posted on May 03,2015 by user-756436 in bathroom exhaust

Articles on mechanical ventilation commonly warn builders that exhaust-only ventilation systems can pull radon into a house through foundation cracks. The warning makes intuitive sense: after all, an exhaust-only ventilation system works by depressurizing a house with respect to the outdoors, and it seems obvious that depressurization could pull soil gases into a basement. One thing I’ve learned over the years, however, is that just because an idea is intuitively obvious, doesn’t mean it’s true. Throughout history, many observers have speculated; far fewer have actually made measurements.

Providing Fresh Air in Our Home

Posted on May 03,2015 by AlexWilson in ERV

One of the features in our new house that I’m most excited about barely raises an eyebrow with some of our visitors: the ventilation system. I believe we have the highest-efficiency heat-recovery ventilator (HRV) on the market — or at least it’s right up there near the top. I’ll describe this Zehnder HRV and its impressive specifications and features — but not until next week. This week I’ll provide a little background on ventilation.

How Much Fresh Air Does Your Home Need?

Posted on May 03,2015 by user-756436 in ASHRAE 62.2

The American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) has had a residential ventilation standard since 2003, when ASHRAE 62.2 (“Ventilation and Acceptable Indoor Air Quality in Low-Rise Residential Buildings”) was first approved for publication. (For more information on providing fresh air for homes, see Designing a Good Ventilation System.)

Ventilation Rates and Human Health

Posted on May 03,2015 by user-756436 in ASHRAE 62.2

Stuffy homes are unhealthy homes, while homes with plenty of fresh air are healthy. That’s been a commonly held belief for at least 200 years. In the mid-19th century, the connection between ventilation and human health was championed by sanitarians, a group of health experts who blamed the spread of bubonic plague and cholera on “miasma.”

Ventilation Requirements for Weatherized Homes

Posted on May 03,2015 by ab3 in ASHRAE

I went to school with Cajuns in south Louisiana, and fights were a big deal. They happened frequently, and when they did, a small crowd would gather. The noise would grow quickly and soon everyone in the schoolyard would run over to where the fight was happening. One day in sixth grade, we exploited this tendency and staged a fight between two shoes at recess. Sure enough — our tight circle of boys banging two shoes on the ground and making a lot of noise brought the whole school to us.

Is There an Alternative to a Heat-Recovery Ventilator?

Posted on May 03,2015 by ScottG in energy-recovery ventilator

The tighter the house, the more it needs mechanical ventilation. That's become a rule of thumb for energy-efficient builders, and designers often turn to heat-recovery ventilators to get the job done. These relatively simple (but not necessarily cheap) devices use the temperature of outgoing air to moderate the temperature of incoming air, thus lowering the energy penalty for providing fresh air to the whole house.

Are HRVs Cost-Effective?

Posted on May 03,2015 by user-756436 in energy-recovery ventilator

From 1977 (when the Saskatchewan Conservation house was built) until 2004 (when the first U.S. Passivhaus was built), North American builders completed hundreds of superinsulated homes. In those days, anyone interested in rating the performance of these homes was probably interested in just one metric: annual energy use.

Weatherization in Alaska Includes Skirmishes with Moisture and Mold

Posted on May 03,2015 by Fretboard in Alaska

Discussions about moisture buildup and its effects are likely to be among the most enduring conversations in homebuilding and remodeling, particularly as more homeowners opt for better-insulated and more-airtight exterior walls.

Mechanical Ventilation for Affordable Existing Housing

Posted on May 03,2015 by Peterbilt in affordable housing

Everyone needs fresh air; it’s just hard to figure out how much we need when we are indoors.

What’s the Most Cost-Effective Way to Bring Fresh Air into a Tight House?

Posted on May 03,2015 by user-756436 in central-fan-integrated

Our Question of the Week focuses on a query from “DC,” a Texas reader who wants to know which residential ventilation system will provide the “most bang for the buck.” DC knows that a tight home requires a mechanical ventilation system to provide fresh air. But how does one choose among the bewildering array of options? And are there any performance advantages to expensive ventilation systems?

Exhaust-Only Ventilation Systems

Posted on May 03,2015 by ShelterNerd in ASHRAE 62.2

After trying a variety of ventilation approaches, I've settled on exhaust-only ventilation systems with ventilation rates that are on the low side of most recommendations.


Posted on May 03,2015 by user-756436 in energy recovery

After investigating various ventilation options, many residential designers conclude that they want either a heat-recovery ventilator (HRV) or an energy-recovery ventilator (ERV). They often remain confused, however, about which of the two devices to choose. Every tight home needs a mechanical ventilation system.

How Tight is Too Tight?

Posted on May 03,2015 by AlexWilson in heat-recovery ventilator

The first question I usually get when I start talking about insulating and buttoning-up houses is, “Won’t my house be too tight?” It’s a very logical question. **Tight houses need fresh air**

Designing a Good Ventilation System

Posted on May 03,2015 by user-756436 in balanced ventilation

UPDATED on March 13, 2015 Most green builders include some type of mechanical ventilation system in every home they build. That’s good. Since green buildings usually have very low levels of air leakage, mechanical ventilation is usually essential. Unfortunately, several research studies have shown that a high number of mechanical ventilation systems are poorly designed or installed.

Green Basics Supply Ventilation
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