Posts

Does Your Exhaust Fan Suck? Part 1

You most likely don’t even think about it when using the bathroom. Flip the switch, hear the exhaust fan, and everything is working as it is intended…right? Far too often, the answer is NO, and it is no fault of the user. Sure, homeowners should take a minute each year to vacuum the inside of the exhaust fan housing, but otherwise, these fans should just work. So why don’t they? Hint…it all depends on how it was sized and installed.

Background

The purpose of exhaust ventilation is to remove contaminants (including moisture) that can compromise health, comfort, and durability. Exhaust fans are amongst the simplest mechanical systems in your home, but decades of experience working in homes has shown us that even the easiest things can get screwed up. Far too often, exhaust fans rated for 50 or 80 cubic feet per minute (cfm) of air removal are actually operating at less than 20 cfm. In theory, the exhaust fan should be installed in a suitable location and then ducted to the outside via the most direct path possible. However, the installation of an exhaust fan can involve up to three trades: an electrician typically installs and wires the unit; an HVAC contractor supplies the ductwork; and, the builder/sider/roofer may install the end cap termination. What could go wrong?

As energy efficiency standards and construction techniques have improved over time, new and retrofitted buildings have become more and more air-tight. If not properly addressed, this air-tightness can lead to moisture issues. Quickly removing moisture generated from showers is a key component of any moisture management strategy. While manufacturers have made significant advancements in the performance, durability, and controls of exhaust fans, these improvements can all be side-stepped by a poor installation.

So how do you correct this issue? Read more

The Second Leading Cause of Lung Cancer May Not be What You Expect

National Public Health Week is this week and Today’s theme is “Environmental Health”, which includes protecting and maintaining a healthy indoor environment.

While National Radon Action Month was in January, we wanted to share how this specific indoor air pollutant can affect your health and what compelled a group of us here at SWA to get our homes tested (and remediated).

What is radon and why does it matter?

Map of EPA Radon Zones

EPA Map of Radon Zones

Radon gas is a naturally occurring byproduct of the radioactive decay of uranium found in some rock and soil. You can’t see, smell or taste radon, but it may be found in drinking water and indoor air. This carcinogenic gas is currently the second leading cause of lung cancer after smoking, according to the National Cancer Institute.

Although radon in drinking water is a concern, radon in soil under homes is the biggest source of radon, and presents the greatest risk to occupants. This pressure-driven mechanism occurs when radon escaping the soil encounters a negative pressure in the home relative to the soil. This pressure differential is caused by exhaust fans in kitchens, bathrooms and appliances, as well as rising warm air created by furnaces, ovens and stoves.

Radon levels can vary dramatically within a region, county, or city. However, the EPA recommends that all homes be tested, regardless of geographic location. To see what the average levels are in your area, check the EPA Radon Zones map.

What radon levels are accepted? Ideal?

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Green Building Targets the Indoor Environment, as Health Becomes Top Priority

SWA_GreenEnergyTimes

In SWA’s second contribution to Green Energy Timeswe examine the certification programs, operational strategies, and occupant behavior trends that contribute to enhanced indoor air quality (IAQ). The full article is featured below, or on page 29 of the April-June edition of Green Energy Times.


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Please Turn on the Fan

I love to cook. And like most cooks, I love to cook on my gas range. But I am also a building science researcher, and the researcher in me doesn’t understand how we allow gas ranges in homes. Building codes and energy efficiency programs have pushed the housing market towards all combustion appliances being sealed combustion and direct vent. Our furnaces, boilers, water heaters, and fireplaces are all going towards sealed combustion. Soon it is likely that building codes won’t even give you the option of using open combustion devices. This push for sealed combustion is an effort to drastically reduce the health hazards of carbon monoxide poisoning and other contaminants in our homes. As a researcher, this makes complete sense to me…but I, like many others, say “Don’t touch my gas range.”

Measuring Carbon Monoxide

My colleague, Steve Klocke, testing the carbon monoxide from his beautiful range.

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Creating a Healthier Indoor Environment

Erica Brabon

Written by SWA Senior Consultant, Erica Brabon

When close to 90% of our lives are spent inside, you would expect extensive measures would be taken to ensure our buildings provide healthy environments in which to live and work. Unfortunately, more often than not, tested air quality inside buildings is much worse than outside.

Here are some common causes of these indoor pollutants:

  • Pesticide use during regular pest control treatments
  • Pollutants (asthma triggers) from cleaning products, smoking, pets, pests, fuel use, etc;
  • Inadequate ventilation;
  • Mold and moisture build up from water leaks and inadequate ventilation; and,
  • Carbon monoxide from appliances, heaters or other equipment.

This problem is made worse by the way in which the pollutants utilize air movement pathways throughout the building. Anywhere air can move, moisture can move and pollutants can move. This presents an intersection of energy efficiency and healthy buildings; air sealing these leakage pathways in the buildings stops pollutants from traveling and saves heating energy.

Let’s revisit the common pollutants and strategies for intervention and mitigation. You’ll notice a common theme of “find the source, stop the source, seal the holes.”

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