Whole House Portable Dehumidifier

[RustyKnuckles]

I've been looking at this dehumidifier:
Frigidaire FAD704DWD High 70 Pints Daily Output SpaceWise Portable Dehumidifier.

Specs say it pulls 7.5 amps.

I have a couple of questions.
Do these portable humidifiers heat up the room appreciably?
Are they noisy?
Thanks.

 

[Stuff]

7.5 amps is equivalent to a 900 watt heater. I think that is max and run cooler but have never done a real measurement of one.
Noise like a window a/c unit as they have the same internal design.

 

[Sponsor]

 

[Fitter30]

From supplyhouse.com
Many manufacturers rate their pint-per-day dehumidification capacities at saturation, meaning at 100% relative humidity, which gives you a false perception of their true capacity to remove moisture. What the manufacturer isn't telling you is that the unit's performance drops significantly at cooler temperatures, which are typically found in basements and crawl spaces, and at more realistic humidity levels. A better estimate of what a unit is capable of under more realistic conditions is AHAM (80 degrees F, 60% RH). If a manufacturer only gives you saturation or does not state the conditions at which their capacity is rated, divide the capacity stated by 2 and you will have an estimate of the AHAM capacity. What are you tring to accomplish? Big box stores with portible DH will not have one that is rated AHAM.

 

[RustyKnuckles]

Inside my house, the humidity is 85% today, and last summer it would climb to 90%. I'm just trying to stay comfortable. No a/c... yet.
But I don't want something that's going to make the place hotter, nor make a lot of noise. So I will probably not get one of these for now.

 

[Reach4]

Inside my house, the humidity is 85% today, and last summer it would climb to 90%. I'm just trying to stay comfortable. No a/c... yet.
But I don't want something that's going to make the place hotter, nor make a lot of noise. So I will probably not get one of these for now.

An air conditioner will dehumidify and dump the heat outside. The downside is that you can't say you don't use a/c. The mini-splits are efficient, but not portable. The portables with the hose(s) out of a window are not as efficient.

Window air conditioners can be worthwhile. The have become more efficient than they used to be by putting the water condensed indoors on the outside coils to cool them. They are quieter mainly due to different compressor design. I don't know if the mini-splits use the condensed water, or just dump it.

 

[RustyKnuckles]

I'm not at all against A/C, but I don't have any windows that I could easily install a window A/C in. All my windows are french windows. My house has 2X6 walls, with batt insulation in the walls. I've got cathedral ceilings, and the attic insulation is R-50 to R-60. In summer afternoons, the house is 10+ degrees cooler than the outside air. The house is in S.W. Mo. When I lived in Cal., people would have rectangular openings cut into their exterior walls, and put the "window" a/c unit in the rectangular hole. I do have a spot where that would work, but I'm a little hesitant to begin cutting, if ya know what I mean. Thanks for all the replies. If anybody thinks of anything else, please post away.

 

[Jadnashua]

To maintain the structural integrity of the wall to install most through the wall a/c units, you'd have to either remove the exterior cladding or the interior wall to then install proper blocking. But, it's not all that hard to do. That is, unless the thing is designed to fit between the nominal 16" OC stud bay, then it's much easier.

 

[Fitter30]

Dehumidifier will lower the RH but will raise the temp of your house. Window units aren't energy efficient as a central or mini splits but are noisy. Your electric company might offer a energy audit that should include a blower door test and might offer rebates on equipment. Exactly what are you wanting as for as cooling the whole house or just a room or two?

 

[Martin Boring]

You didn't say what your using for heat in the winter furnace with duct work or not. If no duct work I would go with a mini split or cut a hole and frame out for a PTAC unit they have improvement them a bunch. The mini splits are really catching on.

 

[Reach4]

You didn't say what your using for heat in the winter furnace with duct work or not. If no duct work I would go with a mini split or cut a hole and frame out for a PTAC unit they have improvement them a bunch. The mini splits are really catching on.

Are PTAC units (Packaged Terminal Air Conditioners) much more efficient than a window unit installed through a hole in the wall?

 

[Fitter30]

tac units usually have a higher eer plus after 10-15 years there should be a unit that can use the ptac sleeve.

 

[WorthFlorida]

Yes, dehumidifiers will warm the space.

Dehumidifiers are a small air conditioner in one box dumping cool air and heat in the same space. Not only is there heat generated from its power consumption, the latent heat from the moisture in the air is where most of the heat comes from. As the air passes over the cooling coils (evaporator coils) the air is brought down below the dew point (condensate) and the air then releases the heat and it is absorbed by the refrigerant. It is carried away by the refrigerant first to the compressor and put under high pressure, then the condensing coils where a fan cools down the refrigerant from the ambient air.

The house needs to be closed up for it to be effective and in warm weather a AC unit needs to be running. If you have the budget for central air, there are two stage units with a smaller or slower compressor that runs just to dehumidified. They also slow up the airflow over the coils for more time to extract water out of the air. All this is determined by the thermostat/humidistat settings.

 

[Dana]

I've been looking at this dehumidifier:
Frigidaire FAD704DWD High 70 Pints Daily Output SpaceWise Portable Dehumidifier.

Specs say it pulls 7.5 amps.

I have a couple of questions.
Do these portable humidifiers heat up the room appreciably?
Are they noisy?
Thanks.

(This is a bit late on the response but...)

The amount of heating depends on the amount of moisture it's pulling from the air. The heat of vaporization of water is 970 BTU/lb, (approximately one pint, depending on temperature.) There is the additional heat-adder of the compressor motor, figure on at least 11oo-1300 BTU/pint going as sensible heat into the room, depending on the room's humidity. As the humidity drops, the efficiency drops, increasing the total BTU/pint.

If it's pulling two pints per hour it's something like 2500 BTU/hr of sensible heat into the room, which is a substantial heat rate- the temperature will rise pretty quickly. (That is is at typical design heating load of a small bedroom when it's 0F outdoors, 68F indoors.)

If it's only pulling half a pint per hour it's the equivalent to the amount of heat- a somewhat active walking/standing human is adding to the room.

Inside my house, the humidity is 85% today, and last summer it would climb to 90%. I'm just trying to stay comfortable. No a/c... yet.

Without the temperature to which it's relative, the % relative humidity is a somewhat meaningless number.

A reading of 90%RH @ 70F is the same absolute humidity as 65%RH @ 80F. That level of humidity feels clammy to most people at 70F, but only somewhat sticky (not necessarily terrible) to most people at 8oF.

In-between those temperatures comfort at that humidity level varies person to person- it's a bit high, but not swampy.

 

[WorthFlorida]

If you rarely open the garage door and it seals fairly well, it will help with the humidity. As soon you open the garage door, it's all lost. I think spell corrector changed a word on you.

Hi everyone, I have a problem with my garage. When it is raining there is always wet. I have recently painted my car and because of the humidity, the paint appeared different scratches.

I'm assuming when it rains that the garage gets very damp? Wet would be rain water is coming onto the garage floor. Are you saying the the humidity is so high that the car paints gets wet like a film of moisture?

If you are storing a high priced antique vehicle yes, a dehumidifier will work since the door will be kept closed most of the time. Your daily driver it will help a little. Does the garage have a window that can open?

 

[Fitter30]

Any space that needs to RH lowered it has to have a vapor barrier to keep the transfer of the RH down. Just like insulation to heat. High RH moves to lower RH. With most garage doors and their seals RH will just flow from the outside.