Moisture vapor, pints per kwh...

[tedkidd]

The Ultra-Aire/Santa Fe/Honeywells produce 4-7.9 pints/KWH.
The most inefficients dehus 1.7 pints per KW.
Search "Energy Star dehumidifiers"
Regards TB

If that's the pints per kwh for dehumidifiers, what is cost per pint of say 6-20 seer ac? Anybody know how to figure that?

[beenthere]

If that's the pints per kwh for dehumidifiers, what is cost per pint of say 6-20 seer ac? Anybody know how to figure that?

Look at the units KW rating, then its latent capacity. 970BTUs capacity per pound of moisture condensed.

[beenthere]

I looked up a CZB024 A/C. It removes 2.789 pounds per KWH. At 85 Outdoor temp and 75DB by 62WB indoor conditions.

[dan sw fl]

A 4-ton unit might theoretically produce nearly a gallon per hour (8 #, 16 pints) of condensate in a Very Humid environment. A residence would NOT be considered a Very Humid environment if it consistently maintained < 54% R.H.

4-ton unit would need in the range of 4 kw-hr or 4 pints / kw-hr.

I would guess about 2 to 3 pints/ kw-hr for A/C equipment currently in service.


The SPECS provided by BeenThere are a realsistc expectation.
( Pint = ~ one lb.)

[tedkidd]

So 13 seer = 4 pt/kwh, that means 20 seer = 7 ish?

[beenthere]

An CZH up to 18 SEER line 2 ton in second stage is, 3.436 pounds at 1.5 KW, at same conditions as previous post.

[tedkidd]

!!? Looks about the same!

So were does the higher efficiency make itself apparent, sensible?

[beenthere]

!!? Looks about the same!

So were does the higher efficiency make itself apparent, sensible?

Sorry, fingers got carried a way, that should be 1.0 KW, not 1.5

Its 5.154 pounds at 1.5 KWH.

[tedkidd]

hmmm. Only about 23% more.

Guess the next question is will good dehumidifiers really remove up to 2x that amount per KWH?

[beenthere]

hmmm. Only about 23% more.

Guess the next question is will good dehumidifiers really remove up to 2x that amount per KWH?

Probably not at 50% RH, since their ratings seem to all be at 60%RH.

[tedkidd]

I think you see where I'm going with this...?

[dan sw fl]

So 13 seer = 4 pt/kwh, that means 20 seer = 7 ish?

I CERTAINLY would NOT use a Linear relationship of SEER to extrapolate a Condensate capacity.

[beenthere]

I think you see where I'm going with this...?

I have been in that debate many times before.

[tedkidd]

... So you make me ask the question? Thanks a lot!

Ok:

For people running dehumidifiers 24/7, wouldn't it make a ton more sense to close up and let a/c run?

[beenthere]

... So you make me ask the question? Thanks a lot!

Ok:

For people running dehumidifiers 24/7, wouldn't it make a ton more sense to close up and let a/c run?

I am a proponent of minimizing both natural fresh air infiltration and mechanical fresh air ventilation. Why bring in what you don't want in the first place.

For those homes that need mechanical ventilation, the A/C system can be set up to bring fresh air in when it is running, so that it can dehumidify it before its introduced to the supply air.

Those on the other side of the coin, say it can't.

[teddy bear]

... So you make me ask the question? Thanks a lot!

Ok:

For people running dehumidifiers 24/7, wouldn't it make a ton more sense to close up and let a/c run?

I agree, it makes more sense closing up and keeping the space the temp and %RH you want. When you are in the space you want 75-78^F. You want <50%RH all the time.
When you are not in the space, the temp could vary, especially if you can maintain <50%RH. An air change of fresh air in 5 hours is needed at a minimum when occupied, according the IAQ experts.
All things considered, An air tight home that has a/c that is able to cool down the home to your desire temp during the hottest weather and visitors in a reasonable period of time is important. Maintain <50%RH throughout the various seasons while providing the minimal fresh air change when occupied with a whole house ventilating dehumidifier.
Needless to say, the dehu is not operating when there is a significant cooling load.
If you understand the a/c is unable to maintain <50%RH when there is low/no cooling load and outdoor dew point is +60^F, this solid combination for indoor air quality, comfort, and minimal operating cost. Not cooling when unoccupied will save enough money to provide <50%RH throught the seasons.
The above comments are limited to green grass climates.
Regards TB

[pstu]

So 13 seer = 4 pt/kwh, that means 20 seer = 7 ish?

If you are going to compare standard AC numbers, would not EER be a better one to use than SEER?

Another thing I don't understand well. When you run these numbers, is anyone accounting for the sensible heat gain every dehumidifier has? So while the best dehu might directly draw 7 pints/kwh, there would be some extra kwh required to cool down the house to where it was before. Is that not true?

Thanks -- Pstu

[teddy bear]

As a manufacturer of dehus, we recommend that the a/c remove moisture whenever cooling loads are present. If the a/c is not running enough to keep the home <50%Rh, the dehu operates removing moisture and adding reheat. The added heat makes the a/c a little more, removing more moisture.

On a hot day, a properly set up a/c should maintain <50%RH. On a cool wet day when the home is below the t-stat setting, the dehu is primary %RH control. Therefore the dehu heat is not generated unless the a/c is unable to maintain the ideal %RH. Adding heat to cool wet home also lowers the %RH. +1^F lowers the humidity +2%RH. This always benefical to basement homes or during cool weather.
Regards TB

[tedkidd]

Yep, some older clients will run heat on 70f high humid mornings to cut clammyness.