Home Performance Consultant Discusses Gas Range Safety
Did you know that code allows gas ranges to vent right into your kitchen and emit more parts per million of carbon monoxide than a water heater which vents into your chimney?
Just because it’s legal doesn’t make it safe. Here, Dan tells you what happens when you cook with a gas oven or cook top and how to do it safely.
Tags: carbon monoxide, CO, cooking with gas, energy audit, gas appliance safety, gas oven, gas range, Home performance, home rater, kitchen safety, Wausau
What the heck is R-Value, anyway?
When talking home performance, the issue of R value often comes up. Unfortunately, in many circles “R-Value” has not yet become a household word. I’ve found that many times even well-educated people stare at me going “Huh?” when I mention R value.
So what is R value?
Simple. R stands for “resistance.” R value is a measure of thermal resistance. Without getting technical, that means it’s a measure of how hard it is for heat to pass through a material.
Now here’s where it gets a little more complex. You can’t measure the resistance to flow. You can only measure the flow of heat. Heat flow is measured as U value. A U value of 1 equals 1 BTU per hour per square foot per degree of temperature differential.
“Now wait a minute,” I can hear you saying. “You just said R value is a measure of resistance. Then you said you can’t measure resistance. Now I’m really confused. What gives?”
Well, yeah. You can’t measure resistance. But when we’re talking insulation, we think in terms of resistance. Like, when we put on a pair of mittens it keeps the cold from getting through to our fingers. We want a number that reflects the way we think. So we make one up. Like this:
We take the U value (a measure of heat flow through a material) and take its reciprocal. And that’s the R value.
Fortunately, we don’t usually have to do the math. Most building materials are rated in R value, so that’s the only number most of us need to be aware of most of the time. The higher the R value, the better the insulator, and (at least in theory) the warmer it’ll keep our homes in winter, and more effective it’ll be in keeping cool air in when it’s hot out.
Here are some typical R values for some common building materials per inch of thickness:
- Poured concrete R-.08
- Brick R-.2
- Glass R-.24
- Wood- R-1
- Straw Bale R-1.45
- Fiberglass (loose fill) R-2.5
- Cellulose (loose fill) R-3
- Fiberglass (batts) R-3.1
- Cellulose (dense pack) R-3.5
- Pre-expanded foam insulation (InsulSmart or RetroFoam) R-4.6
- Polystyrene board R-5
- Expanding spray foam insulation R-5.5
- Foil-faced polyisocyanurate panel (new) R-6.8
Stay tuned for the exciting sequel as we reveal why R-value is not always to be trusted.
Tags: cellulose insulation, fiberglass insulation, foam insulation, home insulation, Home performance, insulation, InsulSmart, r value, RetroFoam, thermal resistance
Building Science and Avoiding Problems in Basements
Building Science, a breif definition
Building science is a cross between physics and shop class. It deals primarily with building envelopes (the foundation, exterior walls, and roof of a building), but can also encompass mechanical systems. The walls and roof of a building are intended to keep the building dry, and in a comfortable temperature range. To accomplish this the building must controll air flow, heat flow and moisture flow. Building scientists study these flows and design effective ways to controll them. A failure to understand the basic principles of building science during construction, including remodeling by a homeowner, can lead to significant, and expensive problems.
I recently decided to study up on basement insulation. We covered the topic during my energy consultant’s training last month at Focus on Energy. I have also read about it in blog posts on trusted websites. (Written by college profs with Phd’s in Building Science)
Bad advice abounds on the internet
Then I went out to the Internet and Googled basement insulation. There is an amazing variety of bad advice, mixed with a few sensible comments. Many of the websites recommended a vapor barrier be placed over fiberglass insulated framed walls before covering them with drywall. These websites blame the moisture on basement walls on condensation caused because the walls are cold. This is just incorrect. Basement walls tend to be moist because the surrounding soil is moist, and concrete is capable of conducting moisture. Basement walls get wet from the outside, and must be able to dry to the inside. If a vapor barrier is placed over the framing before the drywall is installed it traps the moisture in the framed wall. The resulting mold and rot is not pretty, and can be downright toxic and dangerous.
The “correct” way to insulate the interior side of basement walls
The correct way to insulate most basements, is to glue expanded polystyrene insulation directly to the foundation wall. Expanded polystyrene is white bead board. It slows down the moisture flow, without stopping it entirely. Next stud framing is placed over the bead board. The stud cavities are filled with unfaced fiberglass insulation. Unfaced because facings are vapor barriers. The fiberglass itself lets moisture pass right through it, allowing the underlying walls to dry inward. The wall can then be drywalled.
A couple of caveats. If a basement has water problems they must be fixed first. Don’t even consider insulating a leaky basement on the inside. The framing should be protected from water wicking up from the floor. A pressure-treated bottom plate is a must. Personally, I would use fiberglass faced drywall which contains no paper a.k.a. cellulose, a.k.a. mold food. Controlling moisture is the main reason we need building science. Controlling airflow and heat flow is much simpler.
Conclusion: Be sure BEFORE you remodel
This is just one of many examples where homeowners can get into serious trouble by remodeling on their own without expert advice. Understanding building science is a must when retrofitting a building to save energy, or designing and building high performance new structures.
Unfortunately, building science 101 has yet to be offered in US high schools, making building science one of the most misunderstood subjects I have ever encountered. Since most people will live in a house someday, and need to operate that house for energy efficiency, perhaps building science 101 should be taught in high school. But until then, it is up to building consultants to bridge the gap between what homeowners know and what they need to know.
Dan Michelsen
Tags: basement insulation, basement moisture, basement remodeling, building consultants, building science, foundation wall, Home performance, mold, vapor barrier
Performance Energy to Offer Home Performance Testing
Dan completed his Home Rater training last week in Madison. Passed the exam with the highest score in the class. Next week he’ll go back down for more specific training in the various home rater programs through Focus on Energy. We’re looking forward to providing the Wausau area with home performance services.
Dan earned a 90% on his Home Rater exam - the highest score one of hte instructors had ever seen!
Energy Efficiency Important to Home Buyers
Being energy efficient could make your home easier to sell.
Trying to sell your home? Being energy efficient gives you an edge, according to the National Association of Realtors (NAR.)
The 2007 NAR Profile of Buyers’ Home Feature Preferences survey and report reveals that over 90 percent of recent home buyers thought energy efficiency was an important consideration when searching for a home to purchase.
Improving your home performance is always a good idea even if you’re not planning to move. Measures like improved insulation, air sealing and updated appliances will more than pay for themselves over time (and maybe faster than you think, depending on what the price of fuel decides to do.)
But if you’ve been hesitating to invest in basic upgrades because you think you might not be able to reap the benefits, relax. You very well could come out ahead by increasing your home’s value – and making an easier sale.
Tags: energy efficient home, Home performance, home sales, home value, National Association of Realtors
Microsoft Announces Free Energy Usage Application
The first step to saving energy is figuring out where you’re losing it. Here’s a new product that may help you do just that:
Microsoft Corp. recently announced Microsoft Hohm, an online application designed to enable consumers to better understand their energy usage, get recommendations and start saving money. The beta application is available at no cost to anyone in the United States with an Internet connection and can be accessed directly by visiting http://www.microsoft-hohm.com.
Microsoft Hohm provides savings recommendations, which can range from placing new caulking on windows to removing air leaks to installing a programmable thermostat. These recommendations are reportedly tailored based on specific circumstances in the consumer’s home including house features, usage patterns and appliances. If consumers don’t provide their data, Microsoft Hohm will base its recommendations on local and national averages. According to the company, Microsoft Hohm will leverage the energy usage data and feedback from its users to refine and improve the accuracy and relevancy of recommendations.
Source: Clean Edge, Inc.
