Latest crawlspace upgrade

[Donald]

I worked a deal and am able to buy dehumidifiers at wholesale so I bought a Santa Fe Oasis 105 dehumidifier. It's a newer Santa Fe dehumidifier where they have started to use digital controls. It's also about 50% more efficient than almost any other dehumidifier in L/kWh.

So I will have two dehumidifiers on smart plugs and two smart RH sensors.

The plan is to never let the RH get above 45% and be able to fix it with the app on my phone for Smart things.

I also have two non-working dehumidifiers in the crawlspace. So they can fail. And crawlspace ones are not easy to buy locally. One I can get out through the access opening. The other one I am not sure.

The current dehumidifier an Aprilaire E100 and it's using 644 watts almost 24x7 except in the winter.

 

[benjamming]

Do you have a preference on brand for these more expensive dehumidifiers?
I have a Sante Fe Force that has failed. Are they usually worth repairing or not? It needs a new compressor after only 6 years.

 

[doitmyself]

Are other options like crawl space encapsulation feasible? Just wondering.

 

[Donald]

Do you have a preference on brand for these more expensive dehumidifiers?
I have a Sante Fe Force that has failed. Are they usually worth repairing or not? It needs a new compressor after only 6 years.

Well the two main brands in crawlspace dehumidifiers are Aprilaire and Santa Fe. Aprilaire has a 5 year warranty and Santa Fe is 6 years. I have a 5 year old Aprilaire that lost refrigerant and according to Aprilaire when that happens you replace the unit. The Santa.Fe might be 15 or 20 years old before it failed. Obviously not a scientific study.

 

[BMWTurboDzl]

I worked a deal and am able to buy dehumidifiers at wholesale so I bought a Santa Fe Oasis 105 dehumidifier. It's a newer Santa Fe dehumidifier where they have started to use digital controls. It's also about 50% more efficient than almost any other dehumidifier in L/kWh.

So I will have two dehumidifiers on smart plugs and two smart RH sensors.

The plan is to never let the RH get above 45% and be able to fix it with the app on my phone for Smart things.

I also have two non-working dehumidifiers in the crawlspace. So they can fail. And crawlspace ones are not easy to buy locally. One I can get out through the access opening. The other one I am not sure.

The current dehumidifier an Aprilaire E100 and it's using 644 watts almost 24x7 except in the winter.

Surely it's encapsulated?

 

[Donald]

Are other options like crawl space encapsulation feasible? Just wondering.

It has a vapor barrier but is not really sealed. But every encapsulated crawlspace gets a dehumidifier. Do they run as much time per hour as mine? Unknown. And unless you have a smart outlet no one really knows.

 

[Donald]

Surely it's encapsulated?

Encapsulation costs a lot. Mine has a vapor barrier but not sealed. Encapsulation would cost $10K to $15K and all it would do it to allow the dehumidifier to run a little less than 60 min per hour.

 

[Astro14]

Encapsulation isn’t a good idea where we are.

We flood during storms, like hurricanes. Water (salt water) gets in the crawl - well over a foot of it during our last hurricane. Encapsulation would not allow the crawl to truly dry out afterwards, because that flood water would penetrate everything, in addition to shorting out any dehumidifier.

So, we have full vapor barrier, and good vents. The wood (sills and joists) is clean, dry and shows no sign of damage.

 

[Donald]

Encapsulation isn’t a good idea where we are.

We flood during storms, like hurricanes. Water (salt water) gets in the crawl - well over a foot of it during our last hurricane. Encapsulation would not allow the crawl to truly dry out afterwards, because that flood water would penetrate everything, in addition to shorting out any dehumidifier.

So, we have full vapor barrier, and good vents. The wood (sills and joists) is clean, dry and shows no sign of damage.

I guess vents can work in some cases. But if the RH outside is 70% and the RH in your crawlspace 60% then vents won't help.

My vents are all blocked off. I have yet to see any water in the sumps in my crawlspace. Always looks bone dry.

 

[RhondaHonda]

Do all your neighbors run a dehumidifier in the crawl space too? I admittedly don’t know much about crawl spaces as they aren’t really much of a thing here. The house I grew up in had one under part of the house but it had small vents and never caused a problem that I knew of. The dirt was super dry underneath, I do remember that.

It just seems super inefficient to run a large dehumidifier or two year round for the sake of reducing humidity a bit. Would you get mold growth if the vents were open and the RH was basically the same as the outside?

 

[SHOZ]

My crawl space is dirt with a two layers of poly. But the water table is so high here the dirt under the house stays wet. It has a drain too. But as the river comes up the water comes up in the crawlspace through the dirt first. It has a couple of vents, I have power ventilation but it's really a struggle to keep the humidity down under 80%, mainly because the high humidity here in the summer.

I have a Bluetooth fan controller that has temp and humidity settings. It's only 4" though and doesn't do too well.

 

[Astro14]

I guess vents can work in some cases. But if the RH outside is 70% and the RH in your crawlspace 60% then vents won't help.

My vents are all blocked off. I have yet to see any water in the sumps in my crawlspace. Always looks bone dry.

Does your street look like this during flooding?

Are you able to use an outboard or go kayaking down the street?

This is moderate flooding, for us. Severe flooding looks worse.

That water level, while deep enough for boats, is below the crawl, but in severe flooding, like a storm, water gets in the crawl space. The brick veneer isn’t water tight, it can’t be, or it would buckle from the water pressure. You can’t build a dam out of brick veneer.

So, no, placing an electric appliance where it will get submerged in salt water just doesn’t make sense. So, we keep the vapor barrier and vent system that has been working for nearly 30 years.

This is just before forecast coastal flooding, when a local news crew set up in front of our house.

If you haven’t had a news crew set up their camera in front of your house, then, we don’t really have comparable situations.

I had a crawl space guy out here last week, to do a bit of work, and we talked about all the options.

Encapsulation and dehumidifier will not work where we are. Now, he would have made a lot more money selling me that option but even he said, “we can’t put a dehumidifier in there, it doesn’t make sense.”

So, we are sticking with how the house was built, but installing new materials.

 

[SHOZ]

I had some new neighbors who bought 2 acers south of me. It's the highest spot around here but still the water will rise in the soil and fill in the low spots.

They wanted to put in a deep crawl space and put all the HVAC and water softener down there. All the new houses on my side of the pond have crawl spaces and they all flood. Seems they can't figure it out. Took me 40 years. If I were to build a new house where I am it would be on a slab. Any crawl space in a new house here has to have flood vents on them to let the water flow through in times of high water as if it gets high enough the river current comes with it.

This is the highest I've seen it out here in 45 years. it was completely surrounding the house but a slim strip of dirt still above the water. Crawlspace was filled to the floor joist.

 

[alarmguy]

I’m curious about the purpose of keeping a crawlspace more dry than the outside atmosphere.

I’m not understanding the reasoning.
The walls of the house and the attic have the same moisture level as the outside atmosphere why try to keep a crawlspace, lower in humidity than the outside atmosphere/air?

Seems like a waste of energy and effort.
My feeling is, I’m wondering why the vents are closed off to the crawlspace, he has a proper vapor barrier and the most he would need is a humidistat controlled fan to draw the humid air out of the crawlspace if that is a concern of his.

 

[Donald]

I’m curious about the purpose of keeping a crawlspace more dry than the outside atmosphere.

I’m not understanding the reasoning.
The walls of the house and the attic have the same moisture level as the outside atmosphere why try to keep a crawlspace, lower in humidity than the outside atmosphere/air?

Seems like a waste of energy and effort.
My feeling is, I’m wondering why the vents are closed off to the crawlspace, he has a proper vapor barrier and the most he would need is a humidistat controlled fan to draw the humid air out of the crawlspace if that is a concern of his.

The crawlspace needs to have the RH below 50% or you will get mold and eventually rot in the crawlspace. Also if you have fiberglass insulation between the floor joists the fiberglass gets wet and heavy and falls down.

The HVAC is in the crawlspace and high humidity on the outside of the HVAC unit where motors and circuit boards are might not be good either.

 

[Astro14]

The crawlspace needs to have the RH below 50% or you will get mold and eventually rot in the crawlspace. Also if you have fiberglass insulation between the floor joists the fiberglass gets wet and heavy and falls down.

The HVAC is in the crawlspace and high humidity on the outside of the HVAC unit where motors and circuit boards are might not be good either.

Completely agree about the mold and rot, including damage to the insulation. Some of our insulation is “hairy” and getting old. Time for new.

But our crawl space is neither big enough, nor high enough above MSL, to have electric equipment. Our primary HVAC is in the attic. And the condenser, like those of our neighbors, is on a raised platform, well above ground level, and thus, well above the crawl space.

Good circulation and good vapor barrier keep the crawl where it needs to be. The house was built in 1996, and all of the wood is dry and free of rot and mold.

 

[SHOZ]

My crawl space usually stays below 65F in the summer. May get down to the lower 40Fs if it gets cold and windy enough outside. So bring in +80F air it had better be low humidity, which usually isn't the case. The house is65 years old but still standing. Look out for termites. It has redwood sill plates and top plates on the walls. Only thing that saved the house....

 

[Cropduster172]

We've got a foundation crawlspace in our beach house. It's got 4 temperature sensitive mechanical vents. The duct work for the downstairs got taken out by Hurricane Sandy and was replaced shortly thereafter. Had fire and bug retardant foam insulation sprayed on the joists and subfloor. It immediately reduced moisture/humidity levels inside the house by 90%, if not more. No encapsulation...just sand and cobwebs. No issues of rot whatsoever. House was built in 1979 and it's in a flood plain but Sandy was the only flooding in 15 years of ownership. Older CCA PT still plates. HVAC is elevated on a PT deck attached to the house at about 40".

 

[alarmguy]

The crawlspace needs to have the RH below 50% or you will get mold and eventually rot in the crawlspace. Also if you have fiberglass insulation between the floor joists the fiberglass gets wet and heavy and falls down.

The HVAC is in the crawlspace and high humidity on the outside of the HVAC unit where motors and circuit boards are might not be good either.

Too low and you will get dry rot. We all have our interests I guess. Not sure the purpose of needing humidity lower than the outside air in most places. Drawing air through the crawl space will keep things dry. I do not think sealing off the crawl in your area is needed.
However, Im not disputing what you want to do as a project. I just think there are efficient ways to keep mold and moisture in control.
Maybe if you lived in Florida or something I would feel different but that doesnt matter to you. just discussing.

https://crawlspaceninja.com/blog/what-should-humidity-be-in-a-crawl-space/

 

[BMWTurboDzl]

Encapsulation costs a lot. Mine has a vapor barrier but not sealed. Encapsulation would cost $10K to $15K and all it would do it to allow the dehumidifier to run a little less than 60 min per hour.

So vapor barrier on the floor only or up the stem walls? Do you still have crawlspace venting to the outdoors?