Q: I’m really confused about the whole green building movement. There seem to be conflicting messages, especially when it comes to products advertised as being green. They appear to be the same products I saw 10 years ago. If it’s so important to be environmentally friendly, why didn’t companies push this agenda decades ago? After all, we’ve been concerned about the earth since the 1970s, right? I want to be a responsible person but don’t want to get hoodwinked.

A: First, let me say that it’s impossible to discuss every facet of the green building movement in this tiny column. The subject is too broad and deep. As much as I hate to say it, thousands of trees have given their lives to publish books on the topic. I’ve always thought that was pretty ironic. One would think that every book or magazine that covers the topic would use 100 percent recycled paper.

Many who attach themselves to eco-friendly building try to cast their participation in an emerald shade of green. Many should use packaging that’s a murky olive hue instead. Some products that purport to be green are in fact impostors.

I’m all for being a great steward of the planet. It’s our job to try to minimize our environmental impact. But greed and personal gain are swirling around this popular movement. I can see why consumers like you are struggling to make wise investments. That, by the way, is one of the real challenges when trying to make green choices.

One of the biggest mistakes people make when they rush to buy green products is not doing their homework. When you’re comparing two products, it often happens that the one that does not toot its own horn about being green is the better product.

A good example is the tankless water heater, which has been on the market for well over a decade. I’ve written extensively about these products and have received lots of feedback from consumers who have bought them. One of the selling points of these devices, according to the manufacturers, is that they provide an endless quantity of hot water.

Many of these heaters are touted as being green and earth-friendly. But homeowners often find that their fuel bill goes up because they, or family members, end up using more hot water than before with a traditional tank storage heater. How green is that? Some would argue that they’re causing more pollution and hogging more of the finite energy that powers the heater.

Another way that green intentions can lead to grief is when you purchase products that contain lots of recycled materials. Some of these can be a headache down the road. Just ask the thousands of homeowners whose homes contain recycled fly ash from Chinese power plants. This fly ash, used as filler in some brands of drywall, is a byproduct of burning high-sulfur Chinese coal. The fly ash inside the drywall is off-gassing chemicals that corrode wiring and plumbing, as well as causing health issues for some of the occupants of the homes that used this drywall. It’s a green nightmare, if there is such a thing.

Trying to use earth-friendly materials can backfire in other ways. Who would ever think that using limestone dust would cause problems? After all, limestone is a very common rock and has been around for millions of years. But when you mix limestone dust and asphalt to add weight to roofing shingles, you create an environment favorable to algae called Gloeocapsa magma. Perhaps you have an ugly black-stained roof that has some of this earth-friendly limestone on it.

As you can see, there can be some unintended and unwelcome consequences when you try to be green.

Tim Carter is a column ist for Tribune Media Services. He can be contacted through his Web site, www.askthebuilder.com.