A common complaint about hardwood floors in arid zones is checking and splitting due to low humidity. Many people believe running a humidifier in arid zones in summer is futile. This is largely due to the fact that an AC unit is a de-humidifier. These will counter act each other but not totally as your AC does not run continually and this counter reaction by the AC unit can be neutralized to a point. However some checking should be expected in your wood flooring as nothing can be 100% effective. I expect to see some verbage to this effect in all manufactures requirements like this for arid zones soon..

In my zone anyway (Southern Arizona) it is still very dry during the summer months down into the single digits until the rains (monsoons) come in mid July to August. Even though one may think it is useless, a humidifying system attached to your HVAC system is still working to keep up the Rh in your home, lessoning the chance your hardwood floor will check.

There are other options such as using a stand alone humidifier with the one in installed with your HVAC system, or even two or three stand alone humidifiers depending on the size of your house. Speak with a qualified HVAC salesman.

Also, quite a few houses like mine have dual cooling systems. I am able to run an evaporative cooling system (MasterCool II) which easily raises the Rh of the home to any manufactures requirements. Then when the rains come I switch to AC.

Humidification of your house in arid zones like Arizona will also help your wood furniture as well as your sinuses. In fact it is very healthy and typically called a healthy relative zone of 35 to 55 % for wood and people too!

After a discussion I had with a consumer who had a bad experience with their wood floor checking I called a Steinway Piano dealer I put a hardwood floor in for last fall. He humidifiers his entire store, winter through summer. In fact he freaked out when I was installing some solid maple in his showroom cus I left the door open when transporting tools in and out. His $100,000 Steinway he had near the entrance needs a constant ambient temp and Rh or the wood will__________ you fill in the blank.

Needless to say I don't have to worry about that maple hardwood flooring. So you see, there really is no excuse for not maintaining your hardwood floor close to manufactures ambient zone requirements. If you really want hardwood and you live in one of these zones you must make an effort to comply with the manufactures requirements if you want your warranty, otherwise if you make a claim an inspector will sjhow up with his hygrometer and that will be the end of that.

G'day!

Editied version from My Blog: http://flooringinstaller.ning.com/profi ... 8lfcapw60f

What humidity level constitutes an "arid zone?"

If I'm thinking about moving to a totally new area, I'd like to know what areas could give me problems with wood flooring. I'd kind of like to pick the flooring before I move there. While running a humidifier 24/7 seems like a solution, the idea that you can't ever turn if off makes me uneasy.

Also, what high humidity level is considered problematic?

All humidifiers have an on/off switch. Even ones built into the HVAC system

Arid zones IMO are areas with less than 20 to 25% on a regular basis and that do drop into single digits like Tucson does. If you look out the window and see giant cactus, best bet is your in an arid zone.

I have heard that high Rh above 65% can easily allow mold to grow. Pretty most all of southern cal is an arid zone.

Second page down. I think Ken may have the moisture map on his site somewhere.

http://www.nofma.org/Portals/0/Publicat ... mation.pdf

Only the inland areas.

How much rain does San Diego get Gary?

The ocean influences the humidity quite a bit. I am about 50 miles from the ocean, yet the humidity I have is almost always the ideal 45 to 50%. Sometimes higher, sometimes lower. The city of San Diego is right on the coast and consistently has RH levels above 60%.
http://www.cityrating.com/cityhumidity. ... =San+Diego
Now San Diego County extends further inland where the RH is lower and less influenced by the ocean. Ca. does have it's deserts ( Death Valley and the Mojave) where the RH can be extremely low at certain times of the year, similar to Nevada. They are way inland, far from the ocean influences.

Yeah I know the humidity is high along the coast, but rainfall? You can be in a arid zone where there is high humidity so this may confuse some people.

Ya, you confused me for sure.

Makes no sense, what so ever.

What, you've never seen a desert next to the ocean?

This was your definition of an arid zone. Now, when you said "less than 20 to 25% on a regular basis", I took that to mean 20 to 25% relative humidity. Is that what you were referring to?

Thinking of San Diego just reminded me of a a show on history channel...no maybe it was some wilderness channel where the topic was deserts and arid zones. I thought I remembered them saying the entire southern Cal was a desert of some degree.
Course without all that Colorado river water they use and water their lawns with there would be no LA or San Diego would there?

Las Vegas has been doing a pretty good job of sucking up all the available water as well. Even though Vegas has the Hoover Dam and Lake Mead (by damming the Colorado ) now they want to suck the aquifer dry as well. Has ranchers in an uproar.

There is a difference between an area's rainfall and available fresh water, and that same area's relative humidity. Since this forum is about wood floors, it is the relative humidity that we are concerned about and has the most effect on wood floors. As exhibited by the coastal regions in S. CA, an area can have low rainfall and little fresh water supply and still be high in RH, due to the ocean's influence. Consider the Pacific Coast areas of Mexico, like Acapulco, Puerto Vallarta and Manzanillo. These areas have a short rainy season and are considered "dry". But the humidity is quite high year round, due to the Ocean's influence. Any homeowner considering wood flooring is well advised to become aware of their particular region's RH averages to learn what steps need to be taken to protect their wood floors, including purchasing an inexpensive humidistat.

I thought that water from the Colorado was collectively shared by four states. Cal sucks up the most and they flood their dang yards to water grass! Talk about a waste.

But your right on thewood and Rh side of things. Which could be really confusing to people who live in arid zones nest to the ocean.

Also, there is alot of misleading info out there telling people to not run a humidifier. But thats for back east and the south, not out west.