Are the wood floors in other parts of the house and it is just the family room where you feel the difference? If so what is different with what is under the family room? Are you on slab, basement, crawlspace? Sounds like insulation is missing somewhere.

If on basement is the family room over an unfinished area of the basement?

If on crawl space - are you missing insulation under the family room?

The floors themselves should not be any form of insulating and if real wood then some gaps is to be expected as wood contracts and expands some. Part of having a natural product. Also unless on a slab and using engineered wood the floors should have been installed on some form of sub-floors so those tiny gaps shouldn't be a source of the floors being colder.

We got some bs about temperatures changing and shrinkage.

No, not BS. Simply a fact.

New house/ new wood/ heating season. Everything is still drying out/ seeking equilibrium.

Do you have a whole house humidifier? If not, get one. Use it.

No way anyone can tell you why the family room floor is colder. We can't walk around the house, peer into the crawlspace, examine the underside of the floor from the basement....

Shrinkage in winter is so common that almost no one (in the industry) will mention it to homeowwners/buyers. The ONE THING you can check = Relative Humidity (RH) in your home. Go to your thermostat and push the button that lets you adjust the humidity (known as a humidistat). Don't have a button for that? Don't panic. At least you know where to 'add' when looking at your HVAC system (a whole home humidifier is needed for most hardwood floors throughout N. America...and it is OFTEN missing...why? Because it is expensive for the builder).

On to the "cold" in the family room. This has many reasons for being. First and foremost: the HVAC system needs to be checked to see if it's output is appropriate for it's size. Secondly the HVAC venting (the metal tubs carrying the heat) are properly sealed and insulated.

Thirdly the INSULATION under the floor is properly installed/applied.

As you can see, the "cold" probably has nothing to do with the wood floor. In fact, most wood floors add some warmth to a room. Not as much as carpet, but much more than tile or concrete.

You have two things going on here: shrinkage and cold. Both can be related to.....wait for it...the HVAC system (Heating Venting Air Conditioning)!

Start with the HVAC inspection and testing. While the 'guys' are there, go ahead and have a look at the insulation provided in the family room.

Also make sure that the floors guys didn’t cover up returns or outlets on the floor. Mine covered up several when they did my floors.

(a whole home humidifier is needed for most hardwood floors throughout
N. America...and it is OFTEN missing...why? Because it is expensive for
the builder).

Building Codes are stricter north of the 48th, which means newer homes are much tighter. And the tighter the home is, in the winter with windows and doors tightly shut, there is typically enough moisture from ordinary household activities that no extra humidity is required to be added.

More often it is overhumidification that is the problem. There is no reason, according to these leading building scientists, to add humidification if the relative humidity is above 25%.

I didn't bother to add humidifiers to my last home and there was no so-called problem with the wood floors.

My house is a DE-humidification nightmare due to it's tightness and lack of energy usage to dry the air out (i.e. air con).

I am not sure where the statement about needed whole house humidification comes from - certainly not my area in the SE US, either.

Those little "cracks" are nothing. The flooring is sitting on sheets of 3/4-inch plywood. You could prove it with smoke.

If you have a ceiling fan in that room, turn it on. The drafts will disappear quickly (a few seconds). If no ceiling fan you can use any fan. Put it on the floor and aim it upwards. All the drafts disappear almost instantly as the warm air gets stirred in with the cold by the fan. I leave a fan on in our vaulted ceiling living room 24/7, or more like 24/365. All day, all year.

The fan will help but you still might want to put rugs in. We had hardwood in a 1930's house for 25 years. Rugs (and fans) were very necessary. We have cold, ceramic flooring on a slab. The fans help, but we also have runners and rugs where we tend to congregate.

I am not sure where the statement about needed whole house
humidification comes from - certainly not my area in the SE US, either.

Building America/Building Science Corp. often recommends whole house dehumidification in those climes.

Addy T , wood will do that it's normal. The good part is your floors are dark so the gaps will blend in.

If this is new construction you might even hear some pops and creaking from your framing in the cold months, keep that in mind as well, nothing to panic about.

As the other posters noted if this house is on basement/crawlspace you might be able to remedy the situation with better insulation. (I'm referring to the cold feeling)

If the meanwhile take Mark's advice and get you some of those he linked.

worthy wrote:

"Building America/Building Science Corp. often recommends whole house dehumidification in those climes."

EXACTLY!

" I am not sure where the statement about needed whole house humidification comes from - certainly not my area in the SE US, either. "

Where I am (high desert of central Oregon), we'll definitely install a whole house humidifier on our new build. The inside humidity of our current home is typically between 10-15% and the floors show it.

Why should hardwood have roof felt underneath Matt?

OP, where is this house? What is underneath the cold floor room? Is the area underneath conditioned (E.G., is it heated/cooled)?

With cold air coming up like that it sounds like an air pressure problem. Either poorly designed ducts that aren't providing proper return air from the space under the cold floor room or exhausting appliances without proper MUA.

google

I am in Ky, and my floors put in either 1966 or 1968 have what looks to be roofing paper under them, you can see the edges of it, by removing a heat vent cover.

My guess (because we have to resort to that) is the OP is on a slab and the cold is from less than great insulation on the slab side (or underneath). Code is relatively lax here and it isn't a huge energy problem but does become a comfort problem. We have hit some low temps in much of the US so it might be a relatively rare problem.

To any poster mentioning insulation, HVAC or anything temperature or humidity related, it is really helpful to give location. As the desert of Oregon is very different than Miami. And Pheonix is very different than Rochester, NY.

Here we need - location, foundation (type and whether conditioned), HVAC type.

And, no, whole house humidification is absolutely not needed in most of the habited part of the US. Needing it is often a sign of excessive air leakage - in my area of the NC (all areas of NC).