humidity

[scott marshall]

We have a 1000 sf basement with 3.75 sides undergrade. We have been experiencing humidity and mold problems since we moved in in July. We beleive all moisture problems from outside source have been solved. We live in Alabama and it has rained most of June and July. We have a 5 ton Trane with varible speed blower. The main level of house is fairly consistent RH at 48-50%. The basement remains between 63-70% even with portable dehumidifier running. I have considered many option from additional unit to control RH to the purchase of dehumidification system. The problem with the portable is the noise and heat. Please make recommendations. I would like to have a neat installation without noise and heat. If one can go into existing ductwork would be a plus.

Thanks,

Scott

[Senior Tech]

Look on aprilaire's website, we have recently put in 3 of their whole house dehumidifiers...seems the customers love them so far, and they are professionally installed in the existing ductwork with some modifications.

[uktra]

How old is the house? Is it finished or unfinished?

[scott marshall]

The house is new construction and is complete.

[uktra]

Are the walls of the basement finished? If so what type of insulation?

[scott marshall]

The walls are 12" cmu filled with concrete and waterproofed on exterior. The interior have 1.5" sprayed cellulose insulation with 1/2" sheetrock. The floors are natural slate over 4" concrete slab with 6 mil vapor barrier. The ceiling is accoutical tile with R13 insulation above.

[uktra]

With new construction, there is a lot of moisture in concrete that dries to the inside. Is the basement heated/cooled by HVAC? Do you have a return in the basement?

[scott marshall]

Yes the basement is heated and cooled with the 5-ton unit that serves the main floor. Yes we have returns in the basement and on the main floor.

[teddy bear]

Originally posted by scott marshall
We have a 1000 sf basement with 3.75 sides undergrade. We have been experiencing humidity and mold problems since we moved in in July. We beleive all moisture problems from outside source have been solved. We live in Alabama and it has rained most of June and July. We have a 5 ton Trane with varible speed blower. The main level of house is fairly consistent RH at 48-50%. The basement remains between 63-70% even with portable dehumidifier running. I have considered many option from additional unit to control RH to the purchase of dehumidification system. The problem with the portable is the noise and heat. Please make recommendations. I would like to have a neat installation without noise and heat. If one can go into existing ductwork would be a plus.

Thanks,

Scott
Several makes of whole house dehumidifiers are available. Check out the Ultra-aire, Santa Fe, and Aprilaire. The Ultra-air and Santa Fe have been around for + seven years. They are ductable and the most efficient dehumidifiers in the world. They remove twice as much water per kilowatt of electricity as residiential units, 45% more efficient than the recently introduced Aprilaire. They are very quiet, more expensive but will maintain <50%RH in your basement without the a/c operating. They are avialable from your local a/c contractor.
http://www.thermastor.com/DesktopDefault.aspx?tabid=245
http://www.thermastor.com/DesktopDefault.aspx?tabid=248

[cem-bsee]

do you have supply vents in the basement?
Are the downspouts extended 10ft?
Does the ground slope 6- 12" away from the house for 10ft?

Was the HVAC system designed to handle the basement?
How old is the house?
What exterior openings into the basement?
Are there wall to ceiling partitions (rooms) in the bsmt?
What does the HVAC contractor state?

[Edited by cem-bsee on 07-28-2004 at 05:56 AM]

[sneezer]

There are a couple of companies that make dehumidifiers (air conditioners) that put the heat into your hot water. Maybe this would work for you. Dehumidifiers work well when their waste heat is not too much of a concern, but you are way South for that to be true most of the year. Maybe a combination of a conventional dehumidifier and the water heater type would help you out.

Nyletherm and E-tech make units that add on to conventional water heaters and ECR International makes a complete unit with a tank.