Basement Humidity - 70% Ok?

[flyboy917]

I have a new home < 1 year old.
The summer humidity level, in my walkout basement, is running 70%. My builder is telling me thats normal. I'm thinking with a 13 Seer/94 AFUE system, if the air was circulated properly the humidity wouldn't be this high. The builder is telling me I need to get a portable de-humidifier unit. I didn't build a new house EVER expecting to need one.
Who's right?

Ps Have not talked with the HVAC installers yet.

[dan sw fl]

Originally posted by flyboy917
I have a new home < 1 year old.
The summer humidity level, in my walkout basement, is running 70%.

GREAT environment for Growing Mold .|. DEHUMIDIFY.

[sadlier]

Do you already have the air conditioner installed?

[cem-bsee]

respritory medics state 35- 55% RH is needed for someone having limited lung capacity -- seems like good criteria for everyone.
read info at CDC.gov & EPA.gov --

go to Indoor Air Quality forum at this site! lots of info there

sizing a hi effeciency unit is critical! this includes the WHOLE system. the system should dehumidify. you should not have to use supplemental appliances.

in short, the RH% must be under 60% always, lower is better. Esp with a new system.

demand that the builder GIVE you a loaner dehum until system is fixed.

Give complaint in writing, now!

[Edited by cem-bsee on 06-11-2005 at 06:51 AM]

[teddy bear]

EPA, American Medical ASS, and ASHRAE recommend <50%RH to control mold and dust mites.
A/c cools to t-stat set point. A/c removes 2 pints of moisture per ton per hour of run. Summer outdoor dew points are +70^F. Infiltrating moisture in fresh air and moisture generated by occupants is approx. 100 pints per day when maintaining <50%RH. Some of the summer in green grass climates, it's rainy and cool during the day . The a/c operates occasionally during these days and seldom over night. We need 50 ton hours of a/c operation everyday to remove the 100 pints to maintain <50%RH. That's a hot day! When we are able to maintain less than <50%RH, we can raise the t-stat several degrees, which also decreases the cost of cooling by 10% each degree we raise the indoor temp. Get yourself a high eff. whole house dehumidifier to maintain <50%RH throughout your home without any a/c operation. I'm involved with Santa Fe & Ultra-Aire which are most eff. dehus made. It's healthy, comfortable, and efficient to maintain <50%RH regardless of the temperature of the home. Several major a/c mfgs. are offering this concept.

[uktra]

Do you have a thermostat and a return in the basement?

[flyboy917]

Originally posted by flyboy917
I have a new home < 1 year old.
The summer humidity level, in my walkout basement, is running 70%. My builder is telling me thats normal. I'm thinking with a 13 Seer/94 AFUE system, if the air was circulated properly the humidity wouldn't be this high. The builder is telling me I need to get a portable de-humidifier unit. I didn't build a new house EVER expecting to need one.
Who's right?

Ps Have not talked with the HVAC installers yet.

Ok, so whats the answer? I'm going to talk with the HVAC contractor Monday morning.
Do I want a system dehumidifier?
Do I want the system itself checked? Is it broken?
Is the ductwork poorly designed?
FYI, been checking my upstair humidity levels over the weekend. 65% average.

I paid big $$$ to upgrade builders grade equipment to 13 Seer/ 94 AFUE. Rheem
I have a 4 ton unit and 1700 sq. feet (3400 in you include the basement). There is very little air flow from any vent downstairs and "yes" they are open. I'm guessing this was intentional since half the lower level is underground.

I'll be damned if I'm going to spend the next 20 years listening to the noise of a portable dehumidifier and dumping the tank once a day.
Especially when the entire house is still under warenty.

Flyboy

[RoBoTeq]

I see high humidity levels in new houses all of the time. During construction the building materials get wet. The block or concrete used for the foundation and basement flooring is very wet. All of the moisture in the building material from the roofing to the first floor wall plates needs to work its way down to the foundation where it eventually is dissapated into the atmosphere.

For this reason it is not uncommon for a basement to be very humid the first cooling season. After the house has gone through a complete heating and cooling season the humidity usually settles down.

See if you can't rent a dehumidifier for this cooling season because you most likely won't be needing it next year.

[Panama]

A relative of mine solved a similar problem in an older (20 years) home by installing gutters and downspouts to get the water away from the foundation.

[flyboy917]

Originally posted by RoBoTeq
I see high humidity levels in new houses all of the time. During construction the building materials get wet. The block or concrete used for the foundation and basement flooring is very wet. All of the moisture in the building material from the roofing to the first floor wall plates needs to work its way down to the foundation where it eventually is dissapated into the atmosphere.

For this reason it is not uncommon for a basement to be very humid the first cooling season. After the house has gone through a complete heating and cooling season the humidity usually settles down.

See if you can't rent a dehumidifier for this cooling season because you most likely won't be needing it next year.

I see your point. However, we moved into the house in July 04.
We have already been through most of summer and all of winter.
So I'm guessing we missed about a month and a half of real cooling.
Still an issue????

[flyboy917]

Originally posted by Panama
A relative of mine solved a similar problem in an older (20 years) home by installing gutters and downspouts to get the water away from the foundation.

It's a new house. It has all of that. What it doesn't have is dry soil. The yard is nothing but clay that never really drys out.

[uktra]

Do yuou have a thermostat and return in the basement? Are the basement walls insulated? With what?

[beenthere]

Your gonna need a dehumidifier for the basement.

Or a whole house dehumidifier.