This type of post is a bit of a snoozer, UNTIL you have to purchase engineered hardwood floors. Only then will you be happy our crackpot team of researchers (okay, just me) did the work for you. Like most things, you have to decide what works best for you in terms of the look and function of your new flooring.
What exactly is engineered hardwood flooring? And why choose it?
This type of floor starts with a bottom core (a "substrate" if you're fancy) of pressed plywood or manufactured wood layers, and is then topped with a nicer wood veneer; this top "wear layer" is the part that's seen once installed. The invisible bottom layers make natural movement easier, which prevents buckling or warping when temps fluctuate. It also makes it more affordable. The top layer gives it the look and warmth of solid hardwood vs. the cheaper, plastic-y feel of laminate.
Here's a rundown of some of the terms and considerations you'll encounter when shopping around for engineered hardwood floors. There are TONS of options and brands out there these days; you have to find the one that has the combination of features you desire.
Aesthetics
Finish: You can choose either pre-finished boards, or choose to finish them once they are installed. In addition to a clear protective coat, pre-finished boards come in all sorts of stain colors, with names like "harvest" and "smoked oak." With unfinished boards, you get the control of choosing the perfect shade. You also get the extra work.
Plank Lengths: Floor boards will come in a box, in varying lengths, ranging from about 49" to the dreaded little 12". There's no way to control what lengths you receive, so don't be fooled by the nice long floor sample. Some brands do give you the upgrade option of longer length boards, so be sure to ask. Otherwise, you can buy more than required and attempt to cull out the very short boards.
Plank Width: This is pretty straightforward. What width you choose just depends on what look you are going for.
1-strip, 2-strip, 3-strip: This refers to the number of grooves on a single wide board, giving the appearance of multiple planks. This makes the floor quicker to lay, but still has the visual effect of smaller width boards.
Wood Grade: Select or Quality grades will have less variation in the grain of the wood and fewer knots. Builder's or Value grades will have more. What you choose depends on how much you care.
Installation
Floating: This is an increasingly popular method of installation, where the boards "float" above the subfloor vs. being affixed. Floating floors are less prone to warping than the glue down method.
Click Lock: This refers to the method of joining the boards together as they are installed over the subfloor. Individual pieces literally lock together in a special tongue and groove system. This makes for easier (and faster) installation, which you should think about if you are doing it yourself, or paying someone by the hour. If it's not a click lock floor, boards might need to be glued to each other first as they are installed.
Underlayment: This is the soft layer, usually foam or plastic, that lies between floating (not glue or nail down) hardwood flooring and the subfloor. Spend a little more on a thicker pad, and you'll reduce noise considerably. Cork is the Ferrari of underlayments.
Glue Down: With this method, the boards are glued directly to the subfloor, most likely concrete. Note that the glue itself can be expensive, so make sure to factor that into your budget. It can also be toxic, so choose carefully and plan for ventilation during installation.
Nail /Staple Down: This is just what it sounds like. The floor boards are nailed down to the wood subfloor. It isn't recommended for your average DIYers.
Durability
Top Layer Thickness: Here we're talking about the thickness of the top wear layer of veneer, which ranges from .6mm to 6mm. Really this number is all about sanding. How many times can you refinish your floors before you hit the "engineered" part of the floor? Stick to top layers with a thickness of over 4mm if you want your floor to last a lifetime (or more).
Janka Scale: This refers to the hardness of each wood species. White Pine is one of the softest, and is easiest to damage. On the other end of the spectrum are more exotic hardwoods like Brazilian Walnut. Choose accordingly depending on expected foot traffic, and your tolerance for worn-looking floors.
Environmental Considerations
It's said that engineered floors are greener due to the comparatively fewer trees used to produce them. However, adhesives used in cheaper manufacturing processes can produce higher formaldehyde emissions. Before you buy, ask about the companies' environmental ratings. Similarly, buy finishing and adhesive products with zero or low VOCs.
(Image: Kitchen from Babypoint Residence by Chroma Design via Houzz)
Dirty Little Secrets of Tidy Families
Hillary & Michael's Refined Roost
Good Food to Share 
The Big Book of Small, Cool Spaces 
Apartment Therapy Presents 
The Eight-Step Home Cure 
Nomade Express Slee...
How To Cook Fluffy, Tasty Quinoa
How to Make Buckwheat Soba Noodles from Scratch
I love my engineered hardwoods! You cant tell the difference and they are much more durable than normal hardwood. Thats why they are often used for home with kids and pets. AND they are easier to lay in uneven basements and dont warp as easy.
One thing to consider. They can't be sanded and refinished because the veneer is typically only 3/8" thick.
The other is issue is the expansion and contraction of the material during the seasons. During dry season you can have gaps between your boards up to 1/4." I recommend installing them during the dry season (winter) with enough room at the ends for expansion of the boards.
I can't imagine what could possibly make me HAVE to buy engineered wood floors.
@textiles, in many buildings, either there is a concrete sub-floor or a rule from a Board about installing floors that require sanding to finish. Engineered hardwood is the only viable option in those instances.
@Obleak1, it is not the only option. A traditional hardwood floor can be installed over a concrete floor - note that the thickness of construction will be larger.
@duane hill - good installation tip - thanks for throwing that in.
it's my understanding that they can be finished provided the top wear layer is thick enough, although i've never done it myself. has anyone else heard otherwise?
@Dabney, I don't recommend refinishing the floor if the veneer is 3/8" or less. I talked to a floor refinisher recently and he typically sands down +/- 1/4" which falls in the 3/8" range.
@duanehill, I have been told (many times) that gluing hardwood plank flooring to concrete will inhibit its natural tendency to expand and contract, and can cause problems. Is this inaccurate?
I hate my engineered floors. They came in a beautiful brazilian walnut but let me tell you, I wish I went hardwood. It's horrible and I would never recommend it. They are beautiful, sure, til you drop something on them and leave a hole... and those holes multiply til you have a speckled look to your floors. NOT for kids and NOT for high heels or pets dropping bones (my big problem) or visitors dropping things (which happens more than you realize when you're nervous about your floors.)
@vbird, it could happen regardless. I put walnut in a model home, hosted an event when it was finished, and found the floor riddled with pock marks from high heels. Some woods are softer than others.
Our engineered wood floors have been great! They can be refinished one time according to the manufacturer. It is a great question to ask at the floor store.
My favorite thing about the wood surface is that it behaves like wood. I have touched up color with furniture markers and ironed dents out with a little steam. They look great 6 years later and I'd absolutely buy them again.
I'm guessing the counters are quartz? Does anyone know the color/brand?
@vbird - how were they installed? if they are the click and lock variety, i think individual pieces can be replaced. so if you have a particularly bad hole, the option is there. again, i've never done it myself...
We got engineered hardwood installed throughout our whole house (1100 sq ft) except for the tiny bathroom and kitchen... and we LOVE it.
I don't think ours can be refinished technically as we went with a real handscraped wood (actual human hands doing each board - no machine scraping so no weird repeating pattern to the scraping when you view in a large room) and it has a slight bevel on the edges, so not sure how that would work.
Considering that we don't plan on being in this house for the next 50 years (maybe another 15?) I'm not worried about the refinishing anyway.
It was a glue-down install since we have a slab foundation, and they were done in 2 days, and the glue used acts as a vapor/moisture barrier as well.
I researched the heck out of the brands and we went with a Southern Traditions/Alamo Hickory (http://www.southerntraditionsfloors.com/hardwood-flooring/Alamo/Hickory/Fannin-flooring.aspx) since the finish was guaranteed for 50 years, it's a US company that is environmentally friendly and the floors are really, really beautiful. The finish is also matte instead of gloss, so it doesn't show footprints or smudges hardly at all... but the cat hair is pretty obvious (probably a good thing since it makes me clean more often!)
It's been 1.5 years .. and other than me stupidly dragging a few heavy pieces of furniture across it when we were putting our house back together after they finished the install, (felt pads on EVERYTHING heavy now!!) it has not scratched or dented. No heel marks, no dents from dropping things, no scratches from pets or anything.
I think you mean "crack" team of researchers. A "crackpot" is someone who's eccentric.
@sypage - ha! you're totally right. thanks for catching the typo. although, maybe it's appropriate here too. :)
Sure, you can choose between white pine and brazilian walnut using durability as your only metric, but some thought given to renewability, speed of regrowth, old-growth forests, transport footprint, ethical labour, American agriculture, and Amazonian rainforests might be nice too.
There's a balance of issues in play.
A few tips from someone that had actually installed and lived with Engineered Hardwood flooring:
Janka hardness means much less with engineered flooring. Often the lower ply layers are less dense wood like pine or even MDF. Because the veneer layer on engineered wood is so thin and the substrate layers are usually softer, these floors are more easily dented. Try to find oak or maple cores if possible.
Floating floors sound hollow and produce more noise than glue down floors (even with a noise reducing underlayment) Keep this in mind with people under you.
Glue down produces better results in my opinion, but remember that this is essentially a permanent installation. If you are going to glue, get the best material you can with a thick veneer that can be refinished at least once.
Hmm we just bought engineered click lock walnut floors for our condo literally yesterday, so not sure what the verdict will be with marks from pets and heels- yet. However from what I have been obsessively researching the thicker your top layer is the better chance to refinish it at some point once maybe even twice, also the thickness helps with it feeling more solid. We are not gluing them on the concrete because our HOA requires underlayment (boo). While I am a bit of a clean freak and neither my wife and I wear shoes in the house, we do have two little doggies, so just in case any accidents happen through the years and the floors need fixing we purchased an extra box as a spare. The beauty of engineered click lock floors is that you can pop out any puzzle piece that needs changing and lay a perfectly new one right back it.
Thank you, Sypage; I literally could not get past that same error. It's so nice to not be the only language geek. :)
Is there a source for the picture? I love the chevron wall...tiles?
Great article! It is excellent advice from professional to newbie home owners who plan installing hardwood floor. Thanks for tips!
Hello: We got a deal on some black engineered hardwood (including the underlay) so we decided to install it in our whole main floor (excluding kitchen and bath). It looks very nice and I really don't mind the added noise from it, however, I do find that it will mark easily and the edges will pick up even with the swiffer vacuum. So needless to say a black sharpie, black floor stain pens and crayons have become our friend. My question is: Can you put a finish on the top of the floor to help to prevent damage to the floor and areas lifting up? It is a floating floor (click, no glue) so I am concerned that this may change the properties of the floor and perhaps make it buckle or some other bad side effect of a top finish. Any help on this idea would be welcome ... if you think this is a dumb idea, I would like to know that too :) Thank you.
In order to put a new, different finish on your floor you'll have to take the existing one off. This is not possible on a floating floor, as the sander would not make even contact with your floor. Unfortunately you're a bit stuck with the finish you have on there.
Most of your comments are spot-on except the bit about janka. An engineered wood uses the exact same hardwood as with solid floors, except it acts as a veneer. The surface denting tolerance remains completely unaffected.
That floor is beautiful! What was the price per sq ft?