Arlington Energy Smackdown

As you may know, we have a very knowledgeable team guide, Dave Conna, whom I’ve been peppering with questions. Here is our recent exchange about storm windows…

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May 26, 2008

Hi Dave,

We are replacing our storm windows and were going to go with Harvey,
based on our research. Do you know a brand that is more energy
efficient?

My experience was that it was hard to find companies who manufacture
storm windows - it seems everyone is dropping them in favor of
replacement windows. We want to keep our original windows — we read
somewhere that you can get nearly the same insulation effect by using
good storms. Is this true?

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Hi Laurel,

I have not looked into storm windows in a long time but I am sure what you say is true about them being harder and harder to find. Harvey did make one that tested quite excellently - it was the Tru-Channel model. It had very low air leakage. I don’t know if they still make it - that was about 20 years ago (ugh! do I feel old!).

[They do - here's the site]

That said, the testing is a bit bogus because they have to plug the weep holes to do the test - which is an artificial situation, since plugged weep holes are not a typical condition.

Even so, the bottom line is that window replacements are so costly that they rarely make sense from an energy standpoint. Your primary windows can and should be weatherstripped when you add good storms - otherwise the storm window may end up tighter than the prime window so you will get frost on the storm from the relatively moist air that slips in between the two, condenses and freezes. Polyflex is a cheap, durable, and effective window weatherstripping for double hung windows and EFI sells it. It’s pretty easy to install and will make your windows at least 80% better.

Although you won’t have as tight of a seal with the storm and newly weatherstripped prime window and you won’t have Argon gas or a low e coating (you could get low e on the storm, though it would be on the wrong surface for a heating dominated climate like ours), I would still say that you will be plenty happy with good storms instead of whole window replacements. That is the route I would take.

Dave

OK, caveats first.
1. I’m not a scientist or an engineer. Or a plumber or an electrician.
2. I’ve just started learning about solar hot water systems and I’m NO expert.
3. I could go on with caveats all day, but you get the point…

My goal with this blog is really to educate myself. I would also *love* to come up with a group of folks who want to install solar hot water systems this summer so that we can potentially hire a single contractor and use our numbers for a bit of bargaining power…

Quick overview
Apparently solar hot water systems (which generate heat instead of electricity) are more efficient and less finicky about ideal conditions than solar electric (also called photovoltaic, or PV). They are also less expensive and have been around a long time. One installer I spoke with told me, “These time tested solar systems provide an abundance of free hot water for six months of the year, and take up a good portion of the load for the remainder of the year.”

System design
There are lots of kinds of solar hot water systems, but in New England, you need a system that does not heat the water directly or you’d have burst pipes on your roof. These “indirect” systems use the sun to heat anti-freeze. The heat from the anti-freeze is then transfered to your potable water (without any mixing!). These are called “closed loop anti-freeze” systems. I was told that this type of system has a proven track record and that the great majority of installations using this type of system installed in the early 1980’s are still running today.

Components
There are several main components to a solar hot water system:

• collectors get installed on your roof to capture the sun’s heat
• a heat exchanger transfers the heat from the anti-freeze to your potable water
• a storage tank sits in your basement and holds the hot water
• often there is also an electric pump that circulates the anti-freeze from the collector on the roof through the heat exchanger (which is often inside special coils built in to the storage tank) and back up to the collectors
• and of course there are a bunch of pipes that send the anti-freeze around the system, and separate pipes that bring potable water into the storage tank and then up to your faucets.

Research
I have learned a lot from Home Power magazine. They have a bunch of articles and buyer’s guides for solar hot water systems. You can get an annual subscription to their website for $25/year.

My next installment will be on collectors…which of course come in a dizzying variety of flavors and technologies. Man, that stuff gets complicated fast! Last night I was reading about delta T and y-axis intercepts…which for an East Asian studies major was not easy. Please post comments correcting anything that seems wrong, ask questions, or contribute your knowledge and experience! Or just say hi:)
-Laurel

Here are some pretty funny photos of our kick-off rally on May 5th. We all had a great time! Imagine a group of adults (mostly), singing our team cheer:

Rising ocean!
Sinking bears!
Arlington’s the town that cares!
AIM LOW!
Go team go!!

On May 5th, 2008, 31 families in Arlington began a year-long reality TV contest to conserve energy and reduce Arlington’s carbon footprint. Our goal is to make the planet a healthier, safer place…but we wouldn’t mind beating the competition and winning the Energy Smackdown in the process!

Arlington is competing against Cambridge and Medford, and we need your help to win!! To participate in this innovative, grassroots program, visit the contest headquarters. The A-Team will be posting notes about our challenges and our progress here. We hope you’ll follow us on our journey and join in yourselves.

In order for your contributions to be counted in the contest and help Arlington win, you have to sign up. If you have questions, post them here and we’ll try to answer them. Thanks, and go A-Team!
-Laurel