Energy expert Bruce Harley knows about the "dirty work" in home maintenance.

"My background is in engineering. But when I started in energy efficiency 19 years ago, I spent two years in the trenches -- out in the field fixing energy problems in houses: crawling around in attics and crawlspaces, sealing and insulating houses and duct systems," he said. "It's a messy, difficult job, but it was a great education on all the things that can go wrong and waste energy, even though the house may look and 'feel' just fine."

Harley has written a new book, Cut Your Energy Bills Now (Taunton Press). The guide presents 150 ways to save money and make your home more comfortable and green.

If you've been thinking about going green, here are basic things you can do:

1. Reduce your driving (carpool, bike, walk, use public transit), and/or get a more fuel-efficient car.

2. Buy organic food.

3. Reduce your energy at home.

Saving some energy at home is easy -- replace bulbs with compact fluorescents; shut things off when not in use.

"This includes all the stuff that you leave plugged in -- entertainment centers, game consoles, computer equipment and battery chargers. Put them on power strips," Harley said.

He also suggest using standby or sleep mode for your computer rather than a screen saver. Don't set your furnace fan to "On," leave it on "Auto." Dry your clothes outdoors or on a rack.

"But one of my biggest concerns is that people go ahead and do the easy stuff, like replacing light bulbs, and feel like they are living a 'green' life," he said. "That stuff is important to do, but really addressing energy use in the home, as well as reducing driving and food impact, in a deeper way is probably the biggest way to make a positive green impact.

"And, the best part is, it's 'free,' you actually end up putting money back in your pocket over time," he said.

A few of the notions in the book are applicable for apartment-renters.

"Of course, fixing big energy problems in houses is typically beyond what tenants can do for themselves," Harley said.

"Actually some smart landlords I know make some money by making their properties very energy efficient, and then paying for utilities themselves," he said. "They can charge a bit more for the rental in the form of a 'built-in' fixed energy cost, the property is easier to rent, more comfortable and they pocket the difference. Everyone wins."

Since 2000, Harley has been Technical Director for Conservation Services Group in Westborough, Mass.

"Most of my work now relates to research, technical development and support of CSG's programs, and policy-related work, but I always maintain that connection to the hands-on world of real houses."

As with any household project, a quest to go green may not go as precisely as planned at first.

"I try very hard to watch and listen to other folks and learn from their mistakes whenever I can," Harley said. "Of course, I've made mistakes over the years, some of them in my own home that I built. It's pretty efficient, but I wish I had bought better-performing windows.

"But one benefit of working for a company that services thousands of homeowners through energy efficiency programs is that we have reams of data on 'before' and 'after' results, that show us exactly what works. So we can continually build on and improve our knowledge of what works," he said.

Harley feels there are some misconceptions about going green, such as consumers believing it begins and ends with the easy stuff, like using compact fluorescent bulbs.

"I would say that green stuff like recyclable pens, cloth shopping bags, are so much lower on the impact scale than people realize," he said. "'Paper' or 'plastic' actually doesn't really matter, especially if you drive an SUV to the grocery store.

"Of course they make a difference in the aggregate," he said. "I'm very happy that some computer and cell phone manufacturers, and other consumer electronics makers, are starting to pay attention to the greenness of their products.

"But again, I think some of the 'surface' things actually help fool people into thinking that they are really cutting their environmental footprint in a significant way," he said.

Harley also believes there are overrated green products, like "any insulation products that claim to have special insulation powers derived from 'radiant' or 'reflective' properties," he said. These include foil-faced bubble-wraps and other thin plastics, and even paint. "Like the comic-book superheros, it looks good on paper but they don't stand up in real life." he said.

He also suggests staying away from duct cleaning, "unless you've had a big water-damage event, a plumbing leak, and really think your ducts have mold in them. Duct cleaning is mostly designed to clean out your wallet."

Basic heating and cooling is often an overlooked energy-efficient, green notion. He urges to get them working in good order, not just adequate fashion.

"Plug up holes, hidden in attics or basements, seal every duct seam and connection thoroughly, ensuring a home has a complete and continuous layer of insulation that works properly," Harley said. "A lot of it is paying attention to some simple details."

A whole chapter of Cut Your Energy Bills Now is devoted to heating and cooling.

Harley foresees urgency in the future of the green quest.

"I think we have to go green, real green, in a big way to ensure the survival of life on our planet," he said. "Surface stuff that doesn't really save won't make it in the long run, because it won't make that big a difference in the bottom line. You can't pretend you're not using energy that you are using.

"The proof will be in the gallons of gasoline, kilowatt-hours of electricity, and therms of gas that actually get saved as we collectively make the commitment to truly reducing our environmental impact. And the payoff will benefit us all, and future generations."