And this spring they decided to go for it. Their house (like many on the isthmus) sits at 45º to due south and is hip-gabled, so they were able to put up 25 PV panels by utilizing both the southwest and southeast sides of the roof. They will be able to meet 100% of their electrical needs and still sell several thousand kilowatt-hours a year back to MG&E!

You can see a photo and  read a nice article from the TLNA newsletter here.

A major component of the grant is to provide the community with a consultant who can help interested residents and businesses install a solar system. The consultant can provide technical expertise and answer questions regarding design, permitting and rebate programs. The service is provided at no cost to the resident or business.

And the winning bidder for the contract to provide these consulting services was Walker Energy Systems. I have already talked to several dozen individuals and businesses who are interested in solar energy, giving them detailed information about the costs and benefits, discussing their buildings’ suitability for solar power, and performing site visits to measure the “solar window” over their property for shading or other issues.

If you are a resident of Madison and interested in learning whether solar energy can work on your home or business, you can get started by simply sending an email to solar@cityofmadison.com with your name, address, email and phone number, plus some good times to contact you.

I will first call you for a brief conversation to discuss your interests and give you an idea of the costs and payback. If solar seems like a good fit for your property, we can then schedule a site visit to measure your property’s solar window. I then provide you with a report outlining your property’s potential and with a financial analysis spreadsheet on cost and payback projections.

The MadiSUN program gives Madison residents a quick and easy way to get up to speed on solar energy and find out how well solar energy would work on their property, at no cost to them. You can get more information about the program on the City’s MadiSUN web page.

Consider a solar PV (electric) assessment I did for a homeowner in rural Dane County. The home is a passive solar design from the ’70s, with two stories of south-facing, floor-to-ceiling windows and a substantial amount of tile flooring to absorb heat all day. It has two backup heating sources: a wood-burning stove and some electrical resistance heating recessed into the floor in front of the first-story windows. The house is on-the-grid for electricity, but has no natural gas or LP supply.

The homeowner described their heating situation as primarily passive solar, with a fair amount of wood-heating, augmented with some electrical heating. Sounded like a pretty good design…

As always, the first thing I did was to download their utility records for the past couple of years. If you haven’t done this for your own home, I strongly recommend it: MG&E has a great on-line service that gives you tables and graphs of your energy consumption, and lets you download the data for further analysis. The first step to an energy-efficient home or business is knowing how much energy you use and when.

As soon as I looked at the numbers, I realized that the homeowners’ description of their heating strategy didn’t exactly match the data. Their modest-sized house was using over 15,000 kilowatt-hours per year, nearly double the state average and triple what I typically see for houses of similar size and age!

Of course, being an all-electric house meant that they did have to cook and dry clothes with electricity, but 15,000 kWh/year is still a lot of electricity.

The owner was a bit puzzled at how high their electrical consumption was, as he knew they burned quite a bit of wood and the house was, after all, a passive solar design that generally felt pretty comfortable except during long spells of especially cold and cloudy weather.

A key step in any solar assessment is to measure the building’s “solar window”. The amount of solar energy available to be collected on the roof of a building depends on a number of variables. Some are determined by the latitude and climate of the location (how long the days are, how much cloud cover the area has in a typical year). Others are specific to the building itself (the slope of the roof, the direction it faces, any shading from surrounding tress and buildings). I use a special camera system that photographs the sky from east to west, and then use software that takes the photos and computes the amount of solar energy available in a typical year and the amount that would actually reach a collector on the building’s roof.

And that’s when we learned the punch line to the story: When the house was built 30-odd years ago, they had planted a row of pine trees as a wind-break and privacy screen. The trees are a considerable distance to the south of the house, but had obviously grown quite a bit over the years. The solar window analysis showed that the trees had grown so tall that they were blocking the sun during most of the middle of the day (prime solar heating time) during most the the mid-winter months!

So the data showed, to everyone’s surprise, that they really had a wood- and electrically-heated house with a passive-solar assist. We had started out trying to see if solar PV panels could help reduce their electric bill, when the real issue was trees impairing their passive-solar system.

I also noted that a number of the south-facing windows showed signs of fogging, indicating that the thermopane windows had lost their vacuum. This meant that they were letting less sun in and more heat out than they had originally.

So my assessment report advised that, Yes their roof could be a suitable location for solar panels. But the highest priority improvement in which they could invest is to restore the passive solar design by trimming the trees and replacing the failing windows!

I love the idea of generating carbon-free electricity on the roof as much as the next person, but as a solar assessor my job is to give homeowners objective, factual advice about how to get the most benefit for their investment of time and money. It doesn’t make sense to invest in expensive solar PV panels, and then throw the electricity away through leaky windows. First things first: doing conservation measures first, then adding renewable energy hardware is almost always the best policy…

So I decided to whip up a small “Carbon Calculator” spreadsheet to answer the question. It turned out to be so handy that I decided to post it for others to use as well.

It’s pretty easy to use: just go to the yellow-highlighted cells, and enter values for your household. It asks for the miles-per-year and the miles-per-gallon for up to three vehicles, the amount of heating fuel (natural gas, LP or fuel oil), the amount of electricity, and the number of airline passenger-miles consumed by your household.

The screen snapshot above shows my own household’s carbon footprint. We buy 100% of our power from MG&E’s Green Power (wind and solar), so we don’t emit any carbon from our electricity usage (net, over the course of the year). The airline miles (4000 passenger-miles) represent two people taking a single round-trip to a destination 1000 miles away. The heating and electric usage should be available from your utility’s website (MG&E has very good historical data and graphs: you should check out your household’s data if you haven’t already…)

The carbon-content data and the national averages come from the U.S. Energy Information Agency. I don’t have much faith in the EIA’s estimates of future energy supplies, but they do a good job of pulling together statistics on energy consumption. Remember that this is just your household’s direct carbon consumption: it doesn’t count any of the carbon you emit indirectly, particularly the carbon that’s embedded in all the “stuff” we buy and use. But this is the part that’s easiest to directly observe and control, so it’s a good starting point.

The spreadsheet is available for downloading here.

Years ago, I lost a two foot square of plaster over the kitchen sink, from an ice dam that backed up water under the shingles, and pushed it into the attic and onto the ceiling below. I had been a bit bemused at the “old fart” next door, who was out with a roof-rake manicuring his eaves after every snowfall. After I came back from a business trip and found a couple of pounds of plaster in my kitchen sink, I decided that a curmudgeon was just a guy who’d been around long enough to see lots of ways that things can get all fouled up, and he’s tired of fixing messes AFTER they happen!

This winter has certainly proved the wisdom of being pro-active about ice dams: even a small storm with a little build-up is very hard to reverse once it gets established. So take advantage of this record-breaking winter to do a survey of your home’s trouble spots. Maybe take a few photos for reference. They’ll be very useful in talking to a contractor about fixing insulation problems. Next year be sure to start clearing those trouble spots with the very first snowfall. A few minutes of roof-raking after you finish shoveling the sidewalks and driveway can save a lot of hassle and expense from out-of-control ice dams!

Notice the “rumpled” looking snow halfway up the roof? That’s melting snow, warmed from below by heat leaking through the roof. No icicles on the cold porch roof at the left…

Conditions in Madison are perfect for a little house inspection work. Make a note of where ice dams have formed, and that’s where you want to roof-rake after every storm, especially the first one NEXT year!

Lots of icicles points to a generalized lack of insulation:

This extensive a problem shouldn’t be ignored, as it can quickly lead to damaged siding or windows:

Take a look at your roof and gutters today and make note of where insulation needs to be beefed up. Get a roof-rake if you have problem areas, and consider judicious use of heat-tape.

On a well-insulated roof, snow should just sit there until the sun evaporates it. No dripping needed…

I’d heard lots of stories, like “Your plasma TV uses as much electricity as your refrigerator”. But not a lot of hard numbers. So I did some Googling and checking of my own home energy inventory to learn about big-screen TV energy usage.

And the winner is: It Depends! Taking a few random choices of large LCD and Plasma TVs, I was surprised how about half the manufacturers and websites do not list power consumption. At all. Not on their website, not in the user’s manual. Shame!

Plasma TVs do appear to use about 30-50% more electricity than LCD TVs of comparable size.

But the real issue is size: it turns out that today’s larger TVs use 2-4 times more energy than the CRT-style (glass picture tube) TVs they are replacing! The CRTs had gotten pretty energy efficient of late, and the typical CRT TV is a lot smaller than the new big-screens we’re talking about here.

Even within big-screen TVs, size is important: Plasma TVs in the 60+ inch size range draw upwards of 700-800 watts, compared to perhaps 500-600 watts for an LCD of that size.

In the 50 inch range, the percent difference is just as large, but currently prices seem to run against the LCDs in this size range: under $2000 for Plasma models but close to $3000 for LCDs (based on a small, only semi-random sample of sets).

So if you’re shopping for a large-screen TV this year, the first thing to ask yourself is “How big, really?” Remember that all TV pictures, regardless of size, are made up of the same number of pixels: big TVs just have bigger pixels, not more pixels, so you need to sit further away from a larger set for optimum image quality. For many family rooms, a 50″ set is plenty big enough (especially if you’re not planning to upgrade to an HDTV DVD player). Foregoing the 64″ set is the biggest energy savings you can make.

If your room size is genuinely enormous, and only a 64″ set will do, then shop seriously for an LCD. They’re likely to be a little harder to find at a good price, but worth it for the sheer kilowatts involved.

Which brings me back to the refrigerator story. Back-of-the-envelope calculation: A 64″ Plasma TV (800 watts) that’s on for 4 hours each evening uses 3.2 kilowatt-hours per day, or about 1200 kWh/year. About $140 per year to operate.

My refrigerator (150 watts when it’s running) uses about 1.5 kWh/day or 550 kWh/year. About $66 per year to operate.

So there’s one rumor that looks to be true: a big Plasma TV draws 4-5 times as many instantaneous watts as a refrigerator, and uses more than twice as many kilowatt-hours per year!

The City of Madison has just launched a Social Marketing campaign called “Mpowering Madison”. It’s designed to promote the mayor’s “100K Challenge”: a program to urge Madison residents and businesses to save 100,000 tons of CO2 annually.

The Mpower campaign suggests 6 Can-Do’s for reducing carbon emissions:

1. Buy renewable energy
2. Improve energy efficiency
3. Install solar
4. Reduce car emissions
5. Plant trees
6. Conserve water

If you’re interested in Improving Energy Efficiency or Installing Solar, I can help! The Mpower website gives some general tips on how to do these, but it can involve a fair amount of homework to get down to actual plans and priorities. I’ve done the homework, and can walk you through your options, giving you cost and savings information to get the most benefits for the least time and money.

If you’d like help in doing your part to shrink Madison’s carbon footprint while reducing your utility bills, just fill out my Contact Form and we can talk about how to get started…

After months of pushing and shoving in both houses of Congress, and with occasional veto threats from the other end of Pennsylvania Avenue, the House and Senate have each passed an Energy Bill. Totally different energy bills, of course, so now they have to go to conference committee to be reconciled. The Senate has named its members of the conference committee and the House is expected to very soon. Then comes the real sausage-grinding, mostly behind closed doors and out of the spot-light of public attention.

So if you have an interest in renewable energy becoming more affordable to ordinary households, this is a good time to call or write your Representative and Senators. There are several key items you should ask for:

1. Remove the $2000 cap on residential tax credits. Right now, there is a 30% tax credit on investments in renewable energy (solar and wind, in particular), but it’s capped at $2000 per system for residential taxpayers. Businesses can claim the full 30%. For a typical residential solar electric system, the cap means $3000-4000 less in tax credits, compared to a business buying the same system…
2. Do not include large-scale hydro-electric power in the definition of “renewable energy”. When most of us hear “hydro-electric power” we think of the Hoover Dam, or maybe the Wisconsin River dam at Sauk City. But these days, “large-scale hydro” is a code-word for environmentally-destructive Canadian projects that flood millions of acres of northern forests and displace Native Peoples from their ancestral lands. These are the kinds of projects that are driving the construction of high-voltage power lines across Wisconsin, to deliver that power to Chicago and the industrial Midwest. This is NOT “clean power” and should not be allowed to count as part of utilities’ renewable energy portfolios.
3. Support Sen. Reid’s proposal to allow federal funding of high-voltage transmission lines only for those projects that carry at least 75% renewable energy (REAL renewable energy, like solar and wind, not faux-renewables).

These issues aren’t just fodder for policy-wonks; they can make a real difference in how our energy is supplied, who benefits and who suffers: call or write today!

If you’ve ever looked closely at your utility bill, you may have noticed that natural gas is measured (and billed) in something called Therms. A Therm is defined as being equal to 100,000 BTUs (British Thermal Units), if that helps explain things.

Over the past year, I’ve spent a fair amount of time Chasing Therms: trying to understand how and where my own house uses natural gas, and how to reduce that usage. I focused (or perhaps, fixated) on our furnace, a decades-old clunker of a hot water boiler. A little googling on the subject showed me that old furnaces like that are lucky to be 65% efficient, while new EnergyStar furnaces are 90% or more efficient.

Bingo: replacing the furnace should be a big win for our energy use, I decided. And besides, old furnaces always seem to fail late at night on the coldest day of the year, so it made good sense to replace it before it died and start enjoying those big energy savings as soon as possible.

So last fall we decided to get a fancy new computer-controlled, high-efficiency boiler. We also had an old wall-mounted, externally-vented gas heater on our 4-season sunporch. Google said those things are probably under 50% efficient, so we decided to have the installer run hot water lines out there and added a second zone and thermostat just for the sunporch.

Once the first winter’s heating season was over, I downloaded our last two years of utility info from the MG&E website (you can get yours here) and ran the numbers. Of course you have to correct for how cold the weather is from one year to the next, but MG&E nicely includes a column for “Therms-per-heating-degree-day” that takes care of that.

And the news was great: we saw a 25% reduction in how much gas we used overall! We saved almost 300 Therms last winter (and about a ton and a half of carbon dioxide emissions) plus had a more comfortable house as a bonus.

It wasn’t until just recently that I thought to check our non-heating gas usage. It happens that we made some other changes at the same time that we installed the new furnace. We replaced a rather old laundromat-sized gas dryer with a newer stackable unit, mainly to free up floor space for another workbench. We decided to replace our older water heater at the same time as the furnace, again so that it wouldn’t fail and dump water all over the basement floor some night. We spent some time fine-tuning the temperature setting on the new, well-insulated water heater, down to the lowest setting that still gave us good hot showers.

Was I ever surprised when I looked at our summer (non-furnace) gas consumption: Just replacing the dryer and water heater (plus tuning the temperature set-point) reduced our non-furnace gas consumption by over 60%. This saves us about 200 Therms a year, more than twice as much as the new furnace!

Moral: Little things can count for a lot, and can be done a lot cheaper than the big things!