Dehumidification

Kevin_30 · August 2005

Hi everyone. Many people use dehumidifiers to remove humidity from their basements. I have 2-50 pt./day in my basement and the do a good job with the humidity but, of course they put off heat into the room because they have to cool the coil. They make my basement very warm because my basement is warm already. Will an airconditioner remove as much moisture as dehumidifiers? Does it matter how many BTU's of heat they will remove? In other words, will a 5000 BTU air conditioner remove much less humidity than a 15,000 BTU air conditioner?

Mitch_4 · August 2005

air conditining

The beauty of an A/C system (whether you use a central system, or a window unit) is it not only dehumidifies, but it cools as well.

As to whether 5000 vs 15000. it depends on the application. If the AC is too large, it will cool, without properly dehumidifying.

soit would be best to consult a pro for proper sizing.

Window shakers will have a room size chart ie. "this unit is sufficient for "x" sq ft.

A dehumidifier is essentially an AC coil that doesnt reject the heat from the home.

Mitch

Steve Garson · August 2005

I use a window AC along with a dehumidifier. The dehumidifier only comes on if the AC isn't removing enough humidity. Makes the space more comfortable and it actually uses less electricity!

vtheat · August 2005

unico

installing unico cures both problem easily a/c and humidity

enthalpy · August 2005

2006 Band Aids for 10 SEER units

Professor,
Profound thought with the 2006 changes for SEER ratings. Is it going to be a possible issue to match older 10 SEER A/H with 12 SEER condensing units,is it possible to say that it will be no different than the issues of miss matching units like a 3.5 A/H with a three ton condenser.
Don't get me wrong with your new equipment and ECM motors and circuit cards it is done but what about standard units and NO frills.
Can the issues be considered somewhat the same,including either lower or higher than normal suction pressure that can enevibily shorten the life of a compressor; and from these issues come the box of band aids that will really control an A/C system like a refrigeration system, not that it is not done.
The more frequent use of low pressure controls and others like it will be the continuing life support these systems will rely on until equipment is all changed.
What are your thoughts!

Eugene Silberstein 3 · August 2005

There will be issues

Yeppers, there will be issues when half of a 10 SEER system is replaced. Quite often, it will be the 10 SEER condensing unit that is ripped out while the old air handler (tucked away nicely in the attic) remains in service.

Just as with any other system mismatch, the performance of the system will be affected.

It is the job of the contractor to provide the customer with all of the required information sist he customer can make a wise decision. Unfortunately, it ismy prediction that we will be seeing a number of additional system "accessories" added to existing control schemes to prevent evaporator coil freezing and other conditions that will arise as a result of the 10SEER/13 SEER mismatch.

Unfortunately, customers are more willing to replace the condensing unit while leaving the air handler alone, primarily because the air handler cannot be seen. Trust me, if the air handler was located in the front yard, it would be getting replaced as well.

Contractors would also be willing to replace only the condensing unit in an effort to salvage the sale and deal with any system "problems" that would arise from the mismatch situation. Of course, the contactor should informt he customer about the pros and cons of repalcing all/part of the system. For this reason, the contreactor must do his homework and be prepared to answer a lot of questions.

So, as I mentioned before, my prediction is that we will all be seeing an increase in the number of additional control goodies, such as evaporator mounted temperature sensors that will disable the system when the evaporator starts to freeze, that will be installed to keep the system functioning in a relatively acceptable manner.

By the way, Dawn. If you are going to post a new question (one that does not relate directly to the thread being discussed), please click on "NEW THREAD" so we can keep the topics organized. Thanks much and have a great night.

Mike T., Swampeast MO · August 2005

A dehumidifier only adds heat because (like everything mechanical) it is not perfect. The condensing unit fan adds heat as does the compressor mechanism. The process itself is unity gain as you're adding just as much heat back to the air as has been removed from the evaporator coil.

Actually, the heat it adds serves to lower relative humidity. As air gets warmer it holds more water vapor thus relative humidity drops.

Basements are almost always naturally cooler than the outdoors because of their contact with the relatively cool and deep ground. This tends to make the relative humidity in a basement higher than the outdoors.

If you use an air-conditioner (alone) to dehumidify a basement you can have a problem since the air is already relatively cool and humid. To get the humidity level low, you have to cool the air significantly--often to the point of discomfort. (Rather stupid to wear a sweater in the basement in the winter.)

Combine the dehumidifier with a SMALL amount of air cooling and you should achieve good comfort.

Are you getting excessive heat in the basement from your domestic hot water production process? If so, do you best to limit this with insulation.

Dehumidification

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