Wednesday, January 8, 2014

The Whys and Hows of Expanding Foam

     The first thing to know about expanding foams is that there are two distinctly different species.  The first is a one-part that puts out a bead of foam and is applied straight out of the can, or a can mounted on a foam gun.  The second type consists of two cans (thus the name two-part foam) that mix in the hose joining the canisters to put out a spray of foam for larger areas.  Those two canisters can be as small as a can of shaving cream - or weight so much that they may be difficult to lift.  The larger variety usually sits on the floor, and the connecting hose has a nozzle on the end for dispensing the spray.

     Both one and two part foams are made from liquid polyurethane kept under pressure.  When the foam is emitted, it expands and creates a protective barrier that stops the passage of air, gases, water, dust, fibers, and sound.  It also keeps out insects and other unwanted pests.

   Some things make one-part foam a wiser choice than caulk in many situations:  First, the expanding factor - a can of our Purfil foam puts out tens of times more product than a can of caulk.  For instance, one 25 ounce can of one-part foam puts out 1200 feet of a 1/2" bead.  Our Handi-Foam two-part foam expands at an 8 to 1 ratio. Second, foam has a great R-value (insulating value) of 6 to 7 per inch.  Caulk has next to zero insulating value.

     Some things that make two-part foam a better choice than fiberglass in many situations.  Fiberglass can cause irritation to the skin.  It can also be inhaled when fibers break off and are carried through the air, increasing the risk of cancer.   Looking at the MSDS (material safety data sheet) on Purfil one-part, I see that, "None of the ingredients listed are classified by IARC, ACGIH, NTP, or OSHA as carcinogenic".  Unlike foam, fiberglass is susceptible to water damage, which renders it ineffective.   It can also harbor mold spores when water damaged, as many of us found out in the recent Colorado floods.  Then, of course, there is the insulating value as mentioned above.  The R-6.5 per inch for foam compares favorably to the R-3 per inch of fiberglass.  In addition, foams do not shrink or settle, unlike many other forms of insulation.  

     Although foam is easy to work with in that you can cut it, use a foam gun to exactly apply it, and use a cleaner if you make a mistake, it does take some practice to get used to.  Because it expands, it can blow out a door or window frame if the expansion properties aren't understood.  Foam cures with moisture, so it does not work the same in dry and humid climates.  Something else you will quickly discover if you get any foam on your hands, the foam will turn black and be rather difficult to remove. Make sure that you order the foam cleaner along with your foam.  It's a very good idea to wear a mask and gloves when you work with this product.  If possible, it is also advisable to keep the area ventilated until the foam cures.  

    You can see all of our one and two part foams on our website here:

By the way, we are running a manufacturers overstock special on Purfil 1G 24-ounce foam.  The regular cost for a case of 12 cans is $152.00.  While supplies last, the price will be $110.00/case.



Monday, November 14, 2011

Plastic Bags, and Why We Should Ban Them

Rarely have I been as affected by a movie as I have by "BagIt!" This film manages to be informative, entertaining, and inspiring, without being preachy. I'll attempt to do the same. Here are some lessons that I took away.

The correct answer to the question, "Paper or plastic?", is "neither, I brought my own bags". Here are some reasons why: A common estimate is that global consumption of plastic bags is 500 billion annually, which breaks down to 1 million bags used per minute. Why make something that gets used for one hour out of something that takes over a thousand years to degrade?

The production of plastic bags requires great amounts of petroleum, a non renewable natural resource. Toxic chemicals are also employed during the manufacturing process.

About 10% of plastic ends up in our oceans. Presently, there are five great "gyres" or vortices of plastic. We picture a swirling mass of plastic bags - but it's worse than that. The plastic doesn't biodegrade, it photodegrades, which means that it breaks down into a plastic pellet soup that extends into the depths of the ocean and can't be cleaned up. The pellets find their way into the stomachs of marine animals and birds that mistake them for food. The animal's intestines fill up with choking plastic instead. We also take this toxic mess in when we eat these fish, turtles, etc.

Plastic bags are not "free" to the user. The cost of purchase by the vendor is passed on to the consumer, as is the cost of sending this waste to the landfill.

I am by no means perfect, but "BagIt!" inspired me to tighten up on my use of plastics in general. As far as trying to eliminate the use of the plastic shopping bags, I now keep one of those bags that fold up into it's own small pocket in my purse, and one in my backpack. I have also purchased small cloth bags for produce. Here's a good source:

Here in Boulder, Colorado, we're attempting to legislate against the use of plastic bags. We're joining with many other cities, and countries throughout the US, Europe, and Asia. You would be surprised to see he number and variety of places that have either banned, or instituted a fine on the use of plastic bags. Click here to see a partial list:

There are many more reasons not to use plastic, but I suggest you do yourself a favor and see the film.

For more ways to save energy and the environment, see our website,

Tuesday, January 25, 2011

Read All About Us!

This month, we were fortunate enough to be the featured business in the Green America ( newsletter. This fine nonprofit, formally known as Co-op America, is the publisher of several informative peices, including "The Green Pages" business directory.
I am so happy with this article, that I am submitting it here in it's entirety.

January 2011 —
Lower Your Carbon Footprint in 2011

Positive Energy; Boulder, CO

Are you ready for some good news from the green economy? Thanks to stimulus-funding in support of energy-efficiency, green business owner Diane Merker says she's as busy as she's ever been.

Selling products like low-energy light fixtures, programmable thermostats, insulation against home-heat loss, home-energy monitors, and more, Merker's business, Positive Energy, is a one-stop shop for drastically reducing your home-energy use. Energy efficiency for all of us is the first step toward pulling our greenhouse gas emissions way down, and using energy at a rate compatible with widespread use of renewables. Check out our interview with Diane, and check out her blog, Positively Green, for more information on how to save money and energy with Positive Energy.

Green America: What does your business do?

Playing with cars
A compact fluorescent porchlight from Positive Energy.

Diane Merker: I started my company, Positive Energy in 1985 as a bulk-ordering catalog for the 1000 agencies then funded by the Department of Energy (DOE) and Low-Income Energy Assistance Program (LEAP), for purchasing the energy-efficiency products that they installed in low income clients’ homes.

In 1995, I added the online Green Builder’s Catalog (, to sell these same products to the energy-conscious homeowner and contractor. It is hard to believe that just 15 years ago, when I told my mother that I was adding this Web site, she asked, “Why green? Why not another color?” In the time since then, I'm happy to say, “green”, and” energy conservation” have become household words.

What makes your business "green" and what are your most popular products?

Diane: On the Green Builder site, my biggest sellers are low-energy ventilation and whole-house fans. Besides helping the environment, most of the products that I sell also make the home a more comfortable place to be. For instance, besides being low energy users, our fans are super-quiet.

I'm a one-woman operation (with two friends who assist me for a half-day every week, and cover for vacations), and so I control how green my office can be. I use every piece of paper twice, and then recycle. I walk or bike to work every day, and provide bus passes for my two employees. Whatever is shipped from our location goes out in a reused box. I will even admit to cardboard dumpster-diving to find a good box.

What did you do before you started your green business?

Kitchen toys
Use the "Watt's Up" meter to monitor the electricity usage of your household appliance, and replace the biggest energy hogs.

Diane: I moved to Colorado in 1981 to study solar energy. When the solar tax credits disappeared a few years later, and the bottom fell out of that industry, I took a job as an energy auditor for a weatherization program. Realizing the need for bulk buying, I started my business. I thought up the name “Positive Energy,” and knew right away that it was the perfect two-word description of what I wanted to be aiming for.

What are some of the challenges of maintaining high standards of social and environmental responsibility?

Diane: I still struggle with questions about every product that I sell – how much energy is used in transporting the products to the customer, what are the labor conditions in the manufacturers factory, etc. I try to work with small US companies with good practices, but this isn’t always easy. I try to have a personal contact with my vendors, so that I know and trust that their values align with mine.

What has been your proudest moment as a green business owner?

Waldorf doll
Converting your toilet to a dual-flush model with this simple adaptation can save water, energy, and money.

Diane: Really, in every aspect, I am so glad that I made the decision to start my own business 25 years ago. I am often the moderator for our local Green Building Guild’s monthly meetings. I am always proud to look out at the value-oriented, thoughtful, and committed group that assembles and realize that I am a part of this movement.

What's inspiring you now in the green economy?

Diane: Right now, I am inspired by the additional work for weatherization that the government stimulus package has made possible. More low-income homes being made energy efficient means employment for auditors and installers, lower energy bills for homeowners and a cleaner planet for all of us.

What advice would you give to other green entrepreneurs just starting out?

Diane: Be flexible by staying small would be my advice. I added my Web site for homeowners and private contractors when the government stopped funding the DOE weatherization programs. Don’t think that one bad year means that you have to bag the whole thing. After being in business for 25 years, I look at the big picture and realize that there are years that are better, and years that are not so good. If you have a good idea, and love what you do, stick it out, and things probably will turn around.

What is your next green step for the future?

Diane: I am in the fortunate position right now of being too busy (because of the stimulus package) to think about the next step! I would like to work with private energy auditors to make sure that this good work being done in the public sector has a future in the private sector once stimulus funds disappear.

What green product (besides your own!) could you not live without?

Diane: I love our Renai on demand water heater. We have never had a problem with it, it saves on our water heating bill, and we never run out of hot water.

Wednesday, August 4, 2010

Fresh Air 80's and Ventilation

The too tight Home - How to introduce fresh air

On the surface, it seems to make no sense; build a very tight house, and then knock holes in the wall to introduce fresh air. Here's the why and the how.

A well sealed home will certainly save on energy bills, but there is a down side to the too tight home. Pets, cleaning products, cooking, and material out-gasing all produce fumes and odors which need to be removed from the living environment. Carbon dioxide from gas burning appliances needs to be vented out. Moist air needs to exit from the bathroom and kitchen. This exhausted air needs to be replaced by fresh air from outdoors. A very tight house can be a health risk if not properly designed to let out a regulated amount of stale air, and let in regulated fresh air.

When measuring just how much ventilation is needed, we speak in terms of air changes per hour (ACH), in other words, how often the air in a room needs to be replaced per hour to insure proper ventilation. HVAC requires 8 ACH for bathrooms, 15 ACH for kitchens, and 6 ACH for other rooms. For a more exhaustive study (pun not intended) see this site Ventilation (architecture) - Wikipedia, the free encyclopedia.

There are many ways to achieve these levels. They range from energy and heat recovery ventilators which preheat incoming air with the furnace heated exhaust air, to the low cost method of combining inlet vents with exhaust fans. The later is a simple, low cost, lower tech option. Fans rated for quiet, low wattage, continuous run, such as our super cool Panasonic fan can be centrally located, usually in a hallway. In addition, ASHRA (the industry standard) requires that a properly sized fan be installed in every bathroom and kitchen.

The low tech way of replacing this vented air - the Fresh 80 vent passive (read non-electric) air inlet (see picture above). This vent is virtually a way of poking a hole in your wall in a more controlled manner. Usually, one fresh 80 is put in every bedroom, and one in the living room. The vent can be opened or closed, and contains a washable filter. Locating it high up on a wall will allow the cool air entering the room to slowly mix with the interior heated air. When the fan is turned on, it exhausts the stale air, and pulls air in through the Fresh 80's. Do these inlet vents make your room colder - let's just say that we've sold more of these vents in Alaska where houses are super tight, than in any other state!

For more information on ventiltion, see the Ventilation section of our website. Just click here

Thursday, September 24, 2009

Water saving with dual flush toilets

I was up in Calgary, Canada for vacation this summer, and was very happy to see all of the energy conservation measures being put to practice in homes, hotels and businesses. One thing that really caught my eye, were the dual flush toilets, which were even evident in the airport. With a dual flush, you pull the lever up for liquid for a half flush, down for solid for a full flush – thus cutting you water usage markedly. Old style toilets use about five gallons per flush, the new low flows use about 1.6 gallons. In either case, this amount can be cut in half most of the time using the dual flush.

Replacing a perfectly good toilet just to have a dual flush seems impractical, and, although our local recycle center, like many others, does accept, and consequently pulverize donated toilets, this still does not seem like an energy conscious move. The solution, a dual flush conversion kit that can change any toilet into a dual flush, even low flows. We now carry this item on our website,, in the water section.

Here is a some info on how dual flush toilets operate, sourced from the “How Stuff Works” website.

The way water is used to remove waste from the bowl has a lot to do with how much water is needed to get the job done. Standard toilets use siphoning action, a method that employs a siphoning tube, to evacuate waste. A high volume of water entering the toilet bowl when the toilet's flushed fills the siphon tube and pulls the waste and water down the drain. When air enters the tube, the siphoning action stops. Dual flush toilets employ a larger trapway (the hole at the bottom of the bowl) and a wash-down flushing design that pushes waste down the drain. Because there's no siphoning action involved, the system needs less water per flush, and the larger diameter trapway makes it easy for waste to exit the bowl. Combined with the savings from using only half-flushes for liquid waste, the dual flush toilet design can save up to 68 percent more water than a conventional low flow toilet [source: Green Building].

The dual flush toilet uses a larger diameter trapway that doesn't clog as often as a conventional toilet, needs less water to flush efficiently and saves more water than a low flow toilet when flushing liquid waste.

Wednesday, December 10, 2008

For the Energy Auditor

More and more people are now familiar with the term"energy audit", and that's a good thing.  With energy prices climbing, incomes shrinking, and the now undeniable (by anyone's standards) effects of global warming, we should all be getting energy audits.  Many utilities are now offering free or subsidized audits. You can do an energy audit yourself, but you will miss a lot, because a good energy auditor has a good tool bag.  He may have a blower door, an infrared camera, furnace testing equipment, etc.  Here are a few places to find that really thorough certified auditor  ENERGY STAR for Homes Partner LocatorRESNET Certified Rater Directory or FSEC's Energy Gauge Certified Building Energy Raters Directory.  
Now here's the rub - Many people who pay for the audit, and get the recommendations that are going to save them big bucks, never follow through by actually making those improvements.  Find a good insulation company, HVAC contractor, etc, and then look at your state's list to see if any rebates are being offered on the work that needs to be done. Here's a cool site for seeing what is available:  

For all of you energy auditors out there, we have just added a section on "Energy Auditing Tools" at our website

Thursday, July 31, 2008

Of Whole House Fans and Rebates

I've been doing a lot of research lately on whole house fans, and wanted to share some of my findings.  All whole house fans do one thing - and that is to bring night time air through the house and out through the attic.  This cools off the attic (that can get up to 190 in the summer) and the house as well. You close up the house in the morning to keep that night time air inside. Some things that make a whole house fan work better - multi-level homes instead of large one floor ranch houses, a tight home, willingness to open windows at night, close them during the day.
 Energy wise, a whole house fan is definitely a better alternative to an air conditioner in climates where nights are cool and days are hot.  As an example, a typical central air conditioner costs in the neighborhood of $3500.00. A low-energy insulated whole house fan costs in the neighborhood of $1000.00 The operating cost of a low energy fan is about .14/kWH in an area where the cost of a Kilowatt hour is .25 and a home is around 2000 sq. ft.  In the same area, same house, the cost per kWH for running an energy star central air conditioning unit is about $1.52/hour.  You save money, and help reduce strain on the environment.

  There are several things that are important to look at when buying a whole house fan (or, in my case, deciding which are the best fans to put on a website like ours -
1. CFM rating (cubic feet per minute of air that the fan will move)  A good rule of thumb is to purchase a fan with a CFM rating double the square footage of your home.  Many folks buy oversized, over noisy fans which leads to too much energy consumption, and an uncomfortable living environment.
2. Does the fan meet our requirements that it be a low energy user, and that it has some form of insulation that closes with a tight seal when the fan is not in use.  The fans that I've seen that meet this requirement are the Tamarack HV series, the Airscape, and the Quiet Cool fans, with the Tamarack providing the best insulation. 
3.  Is the fan quiet enough that it will actually be used, and still allow you to carry on a normal conversation in your home?  All of the above do this to a less or greater extent - the quietest being the Quiet Cool Series.

Yes, an air conditioner will work better for day time use for those of us living in a hot climate, but here are two options: One, use a whole house fan until inside air gets too warm, and then turn on the AC (maybe just a bedroom window unit). Two, if you live in a dry hot climate, use an evaporative cooler during the day for much lower energy usage.  Better yet, use a whole house fan with an Envirocool two part evaporative cooler.  The wet media and pump part of this swamp cooler is mounted in an exterior wall.  The second half of the swamp cooler, the unit pulling this cooled air through your home, is the attic mounted whole house fan.  Your home is cooled day and night while energy usage is kept to a minimum!  

See our website, for further info on low energy whole house fans  and the Envirocool.

By the way, in many states evaporative coolers, whole house fans, and many other energy efficient products are eligible for rebates and tax credits.  Here's an excellent website that let's you look at what incentives are available in your state.