[012abc]

Sorry if this thread is in the wrong sub. I'm not quite sure where else to put it. Just feel like this sub would fit best for this question.

Single home located in northern Virginia. The home has a walk up basement. Basement is fully underground, and has an exit to the outside. Builder recommend getting a dehumidifier and run it during the summer months. If we do not do this, we will start seeing mold build up in the basement space.

The home has HVAC systems, and is a brand new home. The square footage size of the entire basement space is 1,690.

I was able to find the following dehumidifier. It's rated for 1,500 square feet space. Is this more than sufficient? Is this overkill? If it is overkill, what should be a good size for a dehumidifier for a 1,690 square feet basement space?

Dehumidifier: https://smile.amazon.com/dp/B07JNZFRC8/


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To keep it simple, my best understanding is that mold will start growing at above 50% humidity. Is this correct?

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Thanks.

 

[stick\shift]

1700 ft² is a pretty big basement. I think I'd go with the model larger.

 

[u3b3rg33k]

Thats a tiny machine. usually people get 50/70 PPD units. once you pass 100PPD they start to get way more efficient, the little ones are power hogs.

 

[diyorpay]

Also important:
1.Get a model that continually drains. Many drains are in a corner in the basement, so
2.Provide air movement/circulation

Maybe pay attention to noise rating if that's a consideration.

 

[ktownskier]

Plus one on bigger is better. At least to a point. If it is too small, it will ice over before it removes enough humidity. A dehumidifier is basically an air conditioner, it just doesn't pump the hot air outside the room.

Airflow is very important. If you put it into a room and close the door, it will work primarily on that room. Keep it out in the open and run fans on slow speed to keep the air from becoming stratified.

As well as making sure that you can add a hose that will run to a floor drain. If you don't have a floor drain, but you do have a sink you can drain into, get a condensate pump. You can run your dehumidifier into the pump and then run a tube from the pump into the sink, even if you have to run it in the rafters.

 

[Bud9051]

Hi abc. Brand new so you really don't know what level of humidity you will be seeing.

You have ac, is it circulating through the basement.

Built right the house should be tight enough to limit outside air leaking in, often a major source of moisture in humid locations.

I'm concerned that the builder is advising to install a dehumidifier as HE should have air sealed sufficiently to avoid moisture problems.

Is the basement dry?
Is the basement finished?
I assume the basement has a concrete floor, did he install a plastic barrier below?
Ask him?

Pick up a couple of inexpensive humidity gauges that read both RH and temp. Start recording temp and humidity in the main house and in the basement plus weather reported outside. This will tell you how much humidity you are dealing with and where it is coming from.

Personally, if the house is brand new I would wait to get those numbers.

Bud

 

[surferdude2]

It is possible to sufficiently mitigate a basement humidity problem by providing a/c to the area from an existing system, if it has the capacity. The extra heat load is comparitively small.

Unless you get a dehumidifier that exhausts to the outdoors, it'll heat the area up quita a bit and they can also be noisy and expensive to operate. I have seen that method fall short of customer expectations and approval so many times that I hesitate to recommend it unless there is no alternative.

I'd get full data on the existing conditions and then consult with an HVAC expert for a professional opinion.

 

[user_12345a]

A basement in a new house if well air sealed and properly waterproofed should not require much dehumidification after the first year or two.

Sq ft should not be use to size a dehumidifier - there are other factors.

Fortunately, oversizing dehumidifiers is not that detrimental as long as you don't go like 50% over.

Actual capacity is much lower than stated, as they're rated at 80F/60%rh. A 30 pint can easily only be able to pull 15 pints per day out at 50%/68F.

50 pint is the minimum I would put in most basements.

Properly sized A/C with a return in the basement can adequately dehumidify and it's for the damp days the a/c doesn't run that a dehumidifier is required.

If it is too small, it will ice over before it removes enough humidity.

This is completely wrong, if there's icing the air temperature is too low or there's something wrong with the unit like low refrigerant or plugged coils/filter.

Normally the coil stays above freezing.