residential/mold /prevention/dehumidification

[fastfred]

1--My a/c (cooling/filtering) cycles as needed to maintain the temperature setpoint.
2--My dehumidifier, SantaFe made by Therma-Stor cycles as needed to maintain basement RH setpoint.
My point is the standard less complicated,stand alone systems designed for the specific application seem,in my opinion to be the logical choice.

[dash]

Variable speed blowers and the good controll systems that dehumidify,just aren't that complicated.


They work just fine in humid Florida.

[uktra]

Both are good points. A lot of it has to do with climate, house construction/HVAC sizing & configuration, and individual response to humidity levels. The one thing I like about dehumidifiers is that in mild climates where ther is little temperature call, this unit will keep humidity in the proper range.

[Carnak]

Originally posted by dash
Variable speed blowers and the good controll systems that dehumidify,just aren't that complicated.


They work just fine in humid Florida.

Properly sized AC with a fresh air intake works just fine in the Caribbean. Pressurize and keep the humid air out in the first place.

Positive preesure is not a good winter ventialtion strategy in the North.

[teddy bear]

It,s raining for a week and the highest temperature is 70^F. How does the trickedup a/c remove the 6 gallons of water per day to maintain 50%RH and not turning the home into a walk-in cooler with sweating in the walls behind the drywall.. Give me the details of providing 50,000 btus of latent removal everyday. You need reheat or dehumidification which allows 50,000 btus of latent removal while maintaining the desired inside temperature. Outside ventilation will mean even more latent load in the wet, cool conditions. We owe the truth to our non-teck visitors to this site.

[dash]

Originally posted by teddy bear
It,s raining for a week and the highest temperature is 70^F. How does the trickedup a/c remove the 6 gallons of water per day to maintain 50%RH and not turning the home into a walk-in cooler with sweating in the walls behind the drywall.. Give me the details of providing 50,000 btus of latent removal everyday. You need reheat or dehumidification which allows 50,000 btus of latent removal while maintaining the desired inside temperature. Outside ventilation will mean even more latent load in the wet, cool conditions. We owe the truth to our non-teck visitors to this site.

Some of us are telling the truth!

[Carnak]

Originally posted by teddy bear
It,s raining for a week and the highest temperature is 70^F. How does the trickedup a/c remove the 6 gallons of water per day to maintain 50%RH and not turning the home into a walk-in cooler with sweating in the walls behind the drywall.. Give me the details of providing 50,000 btus of latent removal everyday. You need reheat or dehumidification which allows 50,000 btus of latent removal while maintaining the desired inside temperature. Outside ventilation will mean even more latent load in the wet, cool conditions. We owe the truth to our non-teck visitors to this site.

The answer to humidity control depends on your climate.

In a hot, humid environment, humidity can be successfully controlled with Auto Fan (cycling with compressor) and a fresh air intake. The outside air does add a latent load to the cooling coil but it does not add humidity to the space. The positive pressure elimnates natural infiltration of humid air. It won't over power exhaust fans. Infiltration is the main source of humidity in the space.

Raise your scenario to a week of rain and a high of 80 and you are describing what it is like when a tropical storm/ hurricane passes by. A fresh air intake works well in this situation.

A week of constant rain with a high of 70 the air conditioning will not run unless there are a lot of lights turned turned on, there is a party and a lot of people are home, or some one is baking up a storm in the kitchen.

All rain means no solar gain through windows, high of 70F means no conduction through the building envelope. So in that extreme situation yes run a dehumidifier to control humidity.Is this a consistent climate somewhere, maybe summer in the Alaska pan handle?

Are there over night lows in the 50s?

Let's put things in proper context then, we owe that to the non-tech visitors here.





[Edited by Carnak on 07-15-2004 at 03:40 PM]

[ac4me]

The technically challenged are listening.

I’m building a very tight house with “ICF” concrete walls.
Do you have recommendations for me on a new not yet build house? I live in Tennessee , thanks.

I forgot to say it is single story on slab with the air handler in a large closet.


[Edited by ac4me on 07-15-2004 at 05:23 PM]

[fastfred]

Originally posted by fastfred
1--My a/c (cooling/filtering) cycles as needed to maintain the temperature setpoint.
2--My dehumidifier, SantaFe made by Therma-Stor cycles as needed to maintain basement RH setpoint.
My point is the standard less complicated,stand alone systems designed for the specific application seem,in my opinion to be the logical choice.

With due respect to Dash and teddybear,these guys without
doubt know this subject well.However,I stand by my earlier post. The V/S multistage systems elicit many questions at this forum. Instead of a standard blower motor
"ECM,ICM" test adaptors and expensive to replace. Expensive
therm/hum stats,as well as circuit boards. Relays and contactors are easy to diagnois and less expensive to replace. With stand alone systems if the dehumidifier quits
you can still run the a/c. In low heat load conditions the
dehumidifier can run if the humidity level requires it.
The standard a/c systems,when service is needed,can be repaired by most of the techs in the crew.
As long as we can discuss these subjects we can learn from one another.

[uktra]

ac4me--ICF construction presents items that must be done properly to reap the rewards. First is sizing of the HVAC system. Find someone who knows how to size this type of construction. The old 600 sq. ft. per ton rule of thumb won't work here at all! The second item is the roof. This must be built as air tight and well insulated as possible, or this is the weak link in this type of constuction. Last is that you must have mechanical ventilation if ICF construction is done properly.

P. S. You might want to look at Structural Insulated Panels as an alternative to ICF---it is cheaper and faster and shares almost all ICF's benfits.