Proper Crawl Space Ventilation Can Improve Living Space Air Quality Inside Your Home
There are advantages and disadvantages in having a crawl space under your home.
Advantages, perhaps, a slightly elevated home may be more attractive than a home on a slab.
Plus, you can make repairs and modifications to plumbing, heating, and electrical services.
Disadvantages, a crawl space is an area that is never cleaned.
Under the vapor barrier the humidity is always 100% so mold and bacteria are always present.
Termiticides, other chemicals, even rodent droppings may be present, and odors and gases that emanate will migrate into the home's living space unless proper ventilation is installed.
Whether on a slab or elevated, if radon is present, good ventilation is required.
There are several technologies on the market in regard to moisture control.
One is encapsulation, sealing the crawlspace.
Though this might lower humidity, it's costly and there is no dilution or replacement of stagnant, poor quality air.
Again, if radon is present, ventilation is required.
Another technology is to install a dehumidifier in the crawl space.
This can lower humidity, but again will not dilute or replace the stagnant air.
Another point to think about is that the dehumidifier will be costly to operate.
More importantly, using a dehumidifier requires you to close tightly the crawl space.
Thus, the home's living space air quality is going to be lowered because the crawl space air is not diluted and replaced with fresh outdoor air.
Some systems use a dehumidifier control (dehumidistat) to operate a crawl space vent fan.
This sounds like it's going in the right direction.
However, the technology isn't quite right.
Here's why.
Suppose the outdoor air is getting worse (wetter).
Though the dehumidistat control is in the crawl space, it will quickly recognize this wetter air condition and begin ventilation, even though ventilating is going to make crawl space wetter.
Another problem with a dehumidistat control is that most of them are not made for the difficult environment of a crawl space, so their warranties are short, 30 days to 1 year maximum for the dehumidistat.
There is another system that uses special technology different from all the others mentioned above.
This special technology makes a comparison of the actual moisture content of both the air inside the crawlspace and the outdoor air.
The result is that it pauses and does not ventilate when bringing in outdoor air is going to make the space wetter.
Then, as the outdoor air is getting drier and is able to improve the moisture and air quality in the crawlspace, then this ventilator moves a lot of air which dilutes and replaces stagnant air, ultimately improving your home's living space air quality.
This system, called the Smartvent, is made in the USA, is used from Florida to Alaska...
San Diego to Nova Scotia.
This system is a proven system, and it is the only system to have undergone a year long test where crawl space humidity averaged 46%.
Besides the unique technology this system employs, it also has the longest warranty of all ventilators, five years.
Advantages, perhaps, a slightly elevated home may be more attractive than a home on a slab.
Plus, you can make repairs and modifications to plumbing, heating, and electrical services.
Disadvantages, a crawl space is an area that is never cleaned.
Under the vapor barrier the humidity is always 100% so mold and bacteria are always present.
Termiticides, other chemicals, even rodent droppings may be present, and odors and gases that emanate will migrate into the home's living space unless proper ventilation is installed.
Whether on a slab or elevated, if radon is present, good ventilation is required.
There are several technologies on the market in regard to moisture control.
One is encapsulation, sealing the crawlspace.
Though this might lower humidity, it's costly and there is no dilution or replacement of stagnant, poor quality air.
Again, if radon is present, ventilation is required.
Another technology is to install a dehumidifier in the crawl space.
This can lower humidity, but again will not dilute or replace the stagnant air.
Another point to think about is that the dehumidifier will be costly to operate.
More importantly, using a dehumidifier requires you to close tightly the crawl space.
Thus, the home's living space air quality is going to be lowered because the crawl space air is not diluted and replaced with fresh outdoor air.
Some systems use a dehumidifier control (dehumidistat) to operate a crawl space vent fan.
This sounds like it's going in the right direction.
However, the technology isn't quite right.
Here's why.
Suppose the outdoor air is getting worse (wetter).
Though the dehumidistat control is in the crawl space, it will quickly recognize this wetter air condition and begin ventilation, even though ventilating is going to make crawl space wetter.
Another problem with a dehumidistat control is that most of them are not made for the difficult environment of a crawl space, so their warranties are short, 30 days to 1 year maximum for the dehumidistat.
There is another system that uses special technology different from all the others mentioned above.
This special technology makes a comparison of the actual moisture content of both the air inside the crawlspace and the outdoor air.
The result is that it pauses and does not ventilate when bringing in outdoor air is going to make the space wetter.
Then, as the outdoor air is getting drier and is able to improve the moisture and air quality in the crawlspace, then this ventilator moves a lot of air which dilutes and replaces stagnant air, ultimately improving your home's living space air quality.
This system, called the Smartvent, is made in the USA, is used from Florida to Alaska...
San Diego to Nova Scotia.
This system is a proven system, and it is the only system to have undergone a year long test where crawl space humidity averaged 46%.
Besides the unique technology this system employs, it also has the longest warranty of all ventilators, five years.
