For solar electric, there still are several different kinds of panels; they vary mostly in price and electricity production.  The all require unshaded space, typically on a roof, and work best when tilted at a 45 degree angle or less toward the south (in the Northern Hemisphere, obviously).

We have 16 solar panels on our roof, 4 of which serve as west-facing awnings that help keep the hot afternoon heat our of my office above the garage.  (Since they are flat, at no angle to the sun, they lost about 28% of their productivity compared to having panels angled toward the sun.)  Installed in October 2010, they have generated almost 4 megawatts hours (which includes last winter, when they were entirely covered in snow) to date.  At 9 cents per kilowatt hour, that equates to a savings of $360 on my electric bill.  That’s the worst part about it – electricity is so cheap, that solar gets difficult to justify simply from a financial perspective, unless your rebates and tax credits are really good!  But it is also is equivalent to powering 128 average homes for one day, offsetting 2.7 tons of carbon, and planting 70 trees.  And that’s pretty cool!

Was it worth it?  We had a very unique non-replicable situation with discounts and rebates, so for us, it was a financial no-brainer.   If someone were to ask me about it now, I’d have to do a new analysis, which depends on 3 things (assuming enough unshaded space facing south): the upfront cost, the rebates and tax incentives available, and what you pay for electricity.

The upfront cost is typically in the $17K-$30K range, depending on how much space you have and the size of the system.  The rebates vary across every state.  In Minnesota, for us, Xcel Energy had a $2.75/watt rebate; the State of Minnesota had a $2.00/watt rebate, and the federal government had a 30% federal tax credit on the cost of the entire system.  Definitely check out the Database of State Incentives for Renewable Energy (DSIRE) at www.dsireusa.org for any analysis.  There are often neighborhood grants as well.  Taking all of these things together, you get your total upfront cost.

Then, once you figure out your system size, go to the online PV Watt calculator at  http://rredc.nrel.gov/solar/calculators/PVWATTS/version1/, which will tell you how many kilowatts your system will produce over the course of the year.  Then, find on your electric bill what they charge per kilowatt hour.  (This part is no easy task, if you have an Xcel Energy bill.  There are so many different prices and fees wrapped up in a bill, it is barely comprehensible.)  If you can figure that out, just multiply the cost of electricity by the number of watts your system will generate, and you get your expected savings on your electric bill.

The pros of solar electric is that once installed, there is really no maintenance – especially if you have a grid-tied system and no battery back-up, which we do.  So as utility prices increase, which they probably will, your savings increase.

The cons are the upfront cost and the possibility that they may not look cool — and that’s where I think there is a lot of room in the market to design buildings for solar – so it does look cool, too.

and cooling from the earth to heat and cool the home.  The easiest way to think about it is a heat exchange system uses the earth’s constant 50-55 degree temperature to help you get to your desired home temperature, which is usually between 68 and 72 degrees.  In the hot summer months, think about that outdoor air conditioning compressor that has to work so hard to bring in 90-100 degree air and cool it down.  Instead, the ground source heat pump brings in 50 degree water to help cool the air.   Another benefit is that there is no outdoor air conditioning compressor. 

These larger investments should be considered when thinking about any building or major remodeling.  These are also the items people ask me about, because they know we have a LEED Certified home, which means I did the cost/benefit analysis on all of these things.

It should be noted that everyone should do their own cost/benefit analysis, because the actual up front investment will vary over time, across regions, and even (of course) across contractors.  Utility prices vary widely as well, affecting the payback analysis.  So, how do you do a payback analysis?

Cost / Benefit Analysis 101:

The first and most important thing is to measure only incremental costs and benefits.  And note that I am only referring to financial costs and benefits–those that are quantifiable.  But you have to know what you are comparing it to, otherwise you can’t figure out anything.  So, if you are building a new home, and you have to purchase a full HVAC system, you only want to look at how much more it would be to add on that larger investment.  That’s the initial cost.  Any additional costs, like maintenance or replacement parts, need to be included as well–but again, only incremental to your comparison choice.

On the benefit side, your contractor should be able to tell you a percentage or an amount you might save on either electricity or gas (or both).  For this, you’ll need to look at your utility bills and get an average yearly cost (if you just look at one month, it will be skewed due to weather variations).  So, if you think you might save 30% on your energy bills, and you pay $12,000/year on gas and electric, then your incremental annual benefit will be $4,000.  Here’s the simple payback analysis (my preferred method is discounted future cash flows, but that’s an entire class at business school): if the upfront investment costs an additional $16,000, your payback period will be 4 years.  If you finance your investment, you could be cash flow positive in the first year in the principal and interest on the loan payments are less than the energy savings.

What about the other hard-to-quantify benefits, like less pollution or a quieter home?  There will always be benefits that cannot be directly measured, and these are usually tied with our emotions–which ultimately pushes us toward a decision one way or another.  What’s wonderful about many green investments is that they actually do work out to be a good decision financially, which helps justify what our heart tells us we want to do anyway–because we just feel better about being less wasteful and reducing our dependence on fossil fuels.

Conversely, what’s weird about green investments is that people think they always have to be financially justified, when many other items we buy for our home are never financially justified.  What’s the payback of a beautiful garden?  What’s the financial justification for a more comfortable couch?  There isn’t one – we just like it more.  And that natural, human emotion should be enough justification–if we even need to justify it.  And why do we?

1. Dim the lights.  Ah – a little trickier than just turning off the lights.  Yes, it does make a difference, though an electrician tried to tell me otherwise.  But I have a watt-meter, and when I plug in in a dimmable lamp, I can see that watt usage go down when I dim it down.  That means less energy is being used.
2. Use the stairs instead of the elevator.  I know the elevator is there, and it’s easy, but do you have any idea what an energy hog it is?  Well, neither do I, as the research shows that depending on the type of building and elevator, it varies widely.  But in any case, when you use the stairs, you are using your own energy, and that’s a good thing for your health.
3. Use air to dry things–like your clothes and your hair.  Not only does this save energy, it is actually beneficial to your clothes and your hair!  First, clothing: the lint that needs to be emptied out of the dryer after a load is complete is not just stuff collected on your clothes, it is actually some of the fibers of your clothes.  So, every time you put your clothes in the dryer, it slightly degrades the quality of the fabric. Second: hair.  An 2,000-watt hair dryer used for 30 minutes is equivalent to a 100-watt light bulb turned on for ten hours!  On an annual basis, that’s 365 kilowatt hours, which costs $30-$35/year.  I know some hair styles just have to be blown out, but going with the natural/curly/wavy look every once in a while gives your hair a break and helps save the planet.

And that’s the point: every little thing we do actually does make a difference — and we should feel good about it.  One of the problems I see with the environmental movement is the feeling people have of being morally judged if they are not “green” enough.  And that does not feel good at all; in fact, it can alienate a lot of people, preventing them from doing anything–which does not help matters.  So, I challenge the environmentalists to not hate people who own big houses, not resent large corporations, and not belittle the wealthy man who takes private jets.  Where does that get us, besides further alienating those who can afford to invest in new energy-saving technologies?

How does this save energy?  Primarily it has to do with the amount of energy it takes to mow lawns — usually a weekly endeavor, and usually done with a gasoline-powered mower.  (Of course, if you want to keep that lawn, there are other options: mowing with an electric mower or a push mower is definitely a step in the right direction!)

The other benefit is reduced pollution — both in terms of reduced gas emissions from less mowing, reduced ground water pollution from less lawn fertilizer, and reduced noise pollution, which the neighbors would appreciate. Combustion-engine lawn mowers emit disproportionately large amounts of junk that contribute to smog; the EPA estimates that lawn mowers contribute as much as 5% of the nation’s air pollution.  What’s wrong with smog?  It contributes to asthma and other respiratory illnesses, among other things (like turning the sky a shade of brown, rather than blue)!

As spring is nearing and the snow is melting, it’s a great time to consider the outdoors as part of an overall energy reduction strategy.

1. The first, easiest, cheapest thing to do is to install low-flow aerators in all faucets.  I did this last year, and it took me about 15 minutes to do 5 sinks.  The only tool I needed was a wrench.  What does an aerator do?  Most faucets have a flow rate of about 2.2 gallons per minute, and an aerator will take it down to 1.5 gallons per minute.  It does this by mixing more air in with the water, so you can’t tell the difference in water pressure.  Assuming a faucet is used for 10 minutes/day (teeth brushing, hand washing, shaving), that saves 7 gallons per day — over 2,500 gallons per year — which can really add up over time, both in cost savings and fresh water savings.  Faucet aerators cost between $3 and $20 each;  and some utility companies even offer them for free.  Here’s one on Amazon that takes the flow rate down to 0.5 gallons per minute for under $5: 0.5 GPM Faucet Aerator  Depending on how much water you use, the financial payback makes it a no-brainer.  [youtube=http://www.youtube.com/watch?v=YycSEQHPqZ0]
2. Installing low-flow shower heads are the next easy, inexpensive thing to do.   And since most showers are hot, it’s an energy savings as well: less water to heat.  If you have an old shower head, it can easily use up to 4 gallons per minute; low flow shower heads bring that down to 1.5 gallons per minute — saving families up to 8,000 gallons per year. Some of the newer technology can actually make it feel like there is more water pressure, so there is no sacrifice in the loveliness of a shower.  And for those who have small hot water tanks, it will definitely extend the number of of people who can shower right after one another without running out of hot water!  This one on Amazon has good reviews: American Standard FloWise 3 Function Showerhead.
3. Finally, if you are replacing a toilet, get a dual-flush one.  They are not more expensive than the regular toilets, and they save at least a half a gallon per flush.   There are also dual-flush conversion kits available from Amazon, but I haven’t done this myself so I don’t know how hard they are or how well they work.  Take a look at your toilet to see how many gallons it uses per flush — it may be worth your while to investigate further!

The basic tip is to just make sure the appliance you are buying in Energy Star rated, because it will save you money over time and is better than the alternative.  But I’m focusing specifically on refrigerators, because they are the biggest energy hogging appliance in the home (bigger energy uses are heating, cooling, water heating, and lighting).

Replacing a large appliance like a refrigerator does not seem like the greenest thing to do.  It seems like a waste of many materials by junking an old one, right?  Just like people think they shouldn’t replace their incandescent light bulbs with more efficient ones until they run out.  It starts to get difficult to compare “greenness” when it’s ongoing energy usage that is 70% powered by coal versus junking an appliance and using energy to recycle it, part it out, or send it to the landfill.   That’s why I like to stick to comparing the financials – another type of green that most of us can understand.

So, depending on the model of the old refrigerator, you can save between $100-$200 per year on energy costs alone.  Using the Energy Star’s refrigerator calculator, you can calculate your savings (you just have to know the cost you pay per kilowatt hour, which is about 9 cents in Minneapolis).  Their estimates are pretty reliable because the refrigerator is always on (unlike light bulbs).   If a new refrigerator costs in the $700-$800 range (here is an Energy Star fridge on Amazon for $699), it pays for itself in 3-8 years.  Not a bad financial return.  Plus, you get what is sure to be a much quieter, better looking fridge!

Side note:  Our utility company, Xcel Energy, will even hall away your old one for free, and give you a $35 check.  Now that’s a deal!

There are some things you can do yourself, both easily and cheaply:

1. Add foam padding around electrical outlets.  EHow tells you how; just make sure you turn off the circuit breakers first!)  These can be installed in less than a half hour, depending on the number of outlets in your house.  Where to get them?  Amazon, of course! Foam Outlet Insulators
2. If air is still escaping through the socket themselves, get some child guards that plug into unused outlets.  On cold days, you can really feel the difference, and you get a bonus of blocking something a toddler or dimwit might get hurt from!  Outlet Plugs 36 Pack
3. Add foam insulation around water pipes that may be exposed.  These are pre-slit and super easy to install, and they are also relatively inexpensive.  Just make sure you measure the diameter of your pipes so they fit properly. Foam Pipe Sticks – 0.5 inch

Then there are things you’ll need to hire someone to do, usually involving blowing or installing some sort of insulation in between walls and in attics.   When we built our home, choosing the type of insulation was one of the most difficult decisions to make. Why?  Because we were told that the best R value (a measure of how quickly heat is transferred – you want a high R value) was closed-cell spray foam insulation.  It also has some structural integrity, adding durability to the home, helps prevent mold from growing in between the walls, and is a good sound barrier.

So, what’s the downside?  First, it’s more expensive–but the payoff over time in reduced energy costs I deemed worth it.  But what really got to me was the MSDS sheet – the sheet that requires manufacturers to reveal all the ingredients and their potential hazards.   It was seriously laden with known carcinogens, possible carcinogens, and to top it all off, workers had to be fully covered and masked to spray it.  Once sprayed, though, it becomes inert, so that was reassuring!   We ultimately went with spray foam insulation because nothing else would provide enough insulation in the walls that were already built.

Other options we looked at, and might be more appropriate for existing homes, were recycled cotton denim insulation (better for interior walls), blown cellulose, and the cotton-candy looking (but not feeling) fiberglass (which you can get formaldehyde-free, though I wouldn’t recommend fiberglass at all).

There are other great resources on the web about insulation, and there is not one right answer — except that any insulation is better than no insulation!

blower door test on our home

specifically trained and certified to be a residential energy auditor — which means he probably knows more than you do about the mechanics of your house.  He will come to your home for 1 1/2 -3 hours, depending on the type of audit you request, and he’ll have some cool equipment like a big huge fan for the blower door test and infrared camera.  Second, it’s easy: all you have to do is pick up the phone and schedule it; and most utility companies make it pretty inexpensive.

If you do an internet search for energy audits, you will find many, many companies that offer this service — for an average price of $700, according to the ServiceMagic website.  But both Xcel Energy and Centerpoint Energy, who serve the majority of the population in this metro area, offer extremely subsidized energy audits.

There are various levels of energy audits, and the one that is right for you depends on how much you know already about leaky windows, insulation, and your HVAC system.  Also, if you have ice dams, condensation or moisture issues, or troubling cold spots in the house, a more extensive energy audit would be recommended.  Since I am located in Minneapolis, I’ll give examples unique to this city.  Here’s what I found on the two utilities’ websites:

*must be a temperature differential of around 30 degrees or more between the inside and outside, so spring and fall doesn’t usually work…even this winter of 2012 doesn’t work!

The other benefit of doing this through your utility company is that the utilities themselves offer rebates for most upgrades.  Examples include up to $400 for a new central air conditioner or a tankless water heater.  Most options can be found under the Database of Incentives for Renewable Energy (DSIRE) under State Utility Rebate programs.  Unfortunately, federal tax credits for energy efficiency (with the exception of solar, wind, and geothermal heat pumps–which classify more as renewable energy) all expired at the end of 2011.

Getting an energy audit in and of itself, however, won’t save you any money whatsoever — you have to act on their recommendations.  So, this advice comes early on as low cost thing to do, but really belongs in the bucket of increasing your awareness of how you consume energy, and what you can do to reduce your energy bill.  (I had an energy audit conducted on our old condo, and felt very frustrated by the fact that they leave you alone with their recommendations  — like a consultant that tells you what to do, but doesn’t help you do it!)  Several of my later posts this quarter will address what most likely will be the energy auditor’s recommendations.

We’ve all seen recommendations to bicycle or walk to work, carpool, or take public transportation.  All good things to think about and do.  But that just doesn’t fit into many people’s lifestyle.  So what else can we do besides buying a plug-in electric car (or a regular hybrid, or a diesel, or just a more fuel efficient car), which might not be within our means?

Recently I found out that for every 100 pounds you carry in your car, you lose one mile per gallon in gas efficiency.  As we all probably carry too many unnecessary things around in our car most of the time, I thought that was one of the best motivators to cleaning out my car!   (I actually believe it is ridiculous that every car is equipped with a spare tire to tote around.  Honestly, how many times does that ever get used?!  Re-Go Electric, a Minneapolis based company that converts hybrids to plug-in hybrids, removes the spare tire to make room for the extra large battery.  Nobody has complained.)

Another easy thing to do is make sure there is enough air pressure in all of your tires, as that can cost you a few percentage points in fuel economy as well.   (The owner’s manual or doorjamb will have the recommended tire pressure.)

And finally, for those of us who are hybrid drivers, we have already become aware of how much more gas we burn when we gun it out of a stop light.  Becoming less of a maniac on the road is not only safer, it will save you money.