According to Epson's own specs on the 7900/9900, the lower operating limit for relative humidity is 40%. Essentially impossible in a northern U.S. climate in the winter time. One will need to build a special vapor proof interior room (using drywall with an aluminum foil backing) and with no adjoining outer building walls which would cause potential condensation and then humidify just that room, or tent the machine and humidify the tent, or something like this approach in order to hold Epson's specification during the winter months. When outdoor temperatures go below freezing, indoor humidity levels plummet at ambient indoor temperatures in the human comfort zone. Furnace humidifiers can get you back from below 10% to maybe 20-25% RH, but trying to pump any more moisture into the building and you'll have water running down the walls and windows. Canon's humidity specs are 10% RH on the x100 series printers, and Hp's specs call for 20% minimum on the Z series. How rigidly one should adhere to the manufacturer's environmental operating recommendations, I don't really know, but personally I take them seriously.
Best regards,
Mark
http://www.aardenburg-imaging.com
Mark, I'm not going to beat a dead horse here so this will be my last reply on the subject as well. You telling me about house design and humidity would be like me telling the Pope about Catholicism. House design, building and renovation has been my vocation for about 30 years. I'm not highly specialized in swimming pools and hot tubs per se, but inside a home they push the envelope for humidity control.
Anyhow, above is your first comment regarding humidity, read what you wrote, as I stated before it's inaccurate and almost completely off base, you subsequently changed the rules and before long you will be stating If you live within the Artic circle you will have a difficult time maintaining 20% humidity.
You stated
"When outdoor temperatures go below freezing (approx. below 0 degrees C or 32 F), indoor humidity levels plummet at ambient indoor temperatures in the human comfort zone. Furnace humidifiers can get you back from below 10% to maybe 20-25% RH, but trying to pump any more moisture into the building and you'll have water running down the walls and windows."
This statement is 100% false.
I stated that achieving 40% humidity at 0 is a little more tricky, but certainly not close to impossible. I am not misleading anybody. High humidity and moisture issues are not that difficult to isolate, are your windows wet? Are your outside walls inside wet?
We are speaking about cold climates here, slightly different discussion in Florida, Houston, NO etc.
Epson might engineer and write a specification to cover their asses, imagine that? Epson might know that 25%-35% humidity will take care of 95% of all their printers and so they spec it at 40% and they are covered for any type of warranty claim. When I design a house all structural supports are designed at plus 50% minimum and I read a lot of warranty cards regarding various products and the manufacturers allow themselves a lot of wiggle room. The rule of thumb for controlling humidity in a home especially the wet locations is keep it below 55% and that will keep the water off the walls and between 40%-45% is ideal.
Remember it's a double edge sword, too low humidity will do just as much damage if not more than too much humidity. Wood doors, windows, flooring, furniture are ALL affected by humidity as are many other items.
"That is my cautionary advice to those who would buy an Epson 7900 for a home or office for use in a cold northern wintertime climate. If you locate the printer in a room with at least one adjoining outer wall, and then simply turn on a humidifier to meet 40%RH, you are going to get into trouble with damage to your home or office (if indeed you don't see water running down the windows first)"
And this is the type of blanket statement is just plain misleading and inaccurate. You can't say cold northern wintertime climate. There are a lot of variables and before you do any damage to your home you most definitely will see ice on your windows, more than likely ice instead of water because if they are that poor of a window the cold transfer will keep the water frozen unless you have the heat so high inside the house, but that brings up another problem, furnaces have to be speced correctly to heat a home properly.
And remember, you don't want to completely seal a home, it has to breathe, it's alive!!
"Others can choose to run a humidifier in a cold northern climate for 35-40% RH output and ignore my advice. They will discover for themselves how long they can go before calling in a mould and mildew abatement company."
They wont have to call a mold and mildew mitigation & remediation company, their windows and walls will tell them if they are set too high. The problems with mold and mildews tend to be more in hidden areas below grade, i.e. basements or in houses where old school builders sealed the houses so tight that it trapped the moisture in the walls, we never fell into that trap since we always knew better. Have you ever seen a steam shower inside a home? How about a sauna? There are actually products on the market that will help almost eliminate mold and mildew from growing, special wall boards and paints to name a few. The reason why our clients call us and not you to design and build them a home is because we know what we are talking about.
"I repeat: the typical American home or office building is simply not constructed adequately to do what you are suggesting if it's located in a cold winter climate that routinely falls into subzero temperatures."
You repeat? Read your 1st post which is what I replied to, it never mentions subzero temperatures. I don't even know how you can state unequivocally that the typical American home or office building is simply not constructed adequately to do what I am suggesting, how in the heck do you know this? And what was I suggesting? I suggested that having humidity at 25%-35% inside a home when the temp outside was 0 degrees F was NOT a problem, but that hitting 40% was a little more of a challenge.
OK, enough about humidity inside a house?
Ok, please don't fire back that Antartica ..............................
