It’s a Problem to keep your Crawl Space Vents open all year round!

In 1982 your local building codes started to require crawl space vents to be installed in new “crawl space” home construction.  The idea being that the crawl space under your home needed to be aired out so that fresh air can circulate and dry any moisture that may occur in the mostly enclosed crawl space area.  The problem is that they forgot to consider that moisture comes from the outside air… so rather than drying out the crawl space it is allowing moisture into your crawl space… along with pests, dirt, humidity, heat in the Summer and cold in the Winter.

After 40 years of observation, it is clear that the one size fits all “100% year-round open vent strategy” has its flaws.  Consider this…

The Reasons to Close your Crawl Space Vents!

Winter can bring freezing temperatures and the rain/snow can take a toll on your home. Your open crawl space won’t be spared. During this time, everyone turns up the heat.  Some homeowners ignore or overlook the need to close off their crawl space vents.  You don’t want to have to deal with expensive and frustrating repairs if the pipes under your home freeze – it only takes one really cold night.  And you don’t want to pay higher heat bills because your home is sitting on top of an ice cube (the air in your crawl space is the same temperature as it is outside when your vents are open).

Summer brings the hot, hot temperatures.  Open crawl space vents once again will take its toll when your crawl space fills up with hot outside air.  With open foundation vents, if it’s 90 degrees outside it is pretty close to 90 degrees in your crawl space.  In the Summer, leaving your crawl space vents open is like sitting your home on top of a heating pad… and air-conditioning bills go much higher than they need to be!  If you don’t have air-conditioning then you are still sitting on a heating pad and heat rises…

Most people think closing your crawl space vents is for the Winter only.  They are losing money 50% of the year.  Close your vents in the Summer heat too.  If you want to air out your home… do it in the moderate weather of Spring or Fall.  The rest of the year you want to close those vents.

Why they were wrong when they required foundation vents in the first place…

While venting the crawl space theoretically sounds good… I mean with the vents open the air outside can come right in and keep everything nice and dry.  WHAT?  When you open the window, and it is raining does any rain come in your home?  When it is 80% humidity outside do you go around your home and open all your windows?  When it is freezing cold outside do you keep your front door open?  NO!  YOU DON’T!

Yes, moist air that is already in your crawl space could escape through an open vent but the problem is that much more moist air comes in the open vent then goes out. 

  • It doesn’t rain under your home so why not close your vent and keep the moisture out… close your vents.
  • In the hot Summer, the sun doesn’t shine under your home so why let the 90-degree temperatures in – close your vents.
  • It doesn’t have to be 30 degrees under your home in the Winter – close your vents.

The unabated airflow caused by open crawl space vents can ultimately lead to these problems: 

Low Energy Efficiency – Higher Utility Bills. Leaving the crawl space vents open during winter months makes your home less energy efficient. Close your vents and save $$$ on heating and air conditioning bills.

Frozen/Burst Pipes – When temperatures drop below the freezing point, water pipes in the crawl space are bound to freeze if the vents remain open. Deal with it now or deal with it later.

The Stack Effect – Another reason you’d want to close the vents is to prevent the stack effect. In the Winter, when warm air leaves your home when you open the front door… the stack effect results in your home pulling cold air out of your crawl space to replace the warm air that leaves your home every time the front door opens.  Leaving vents open promotes this effect, meaning cold air will continue flowing into your home. 

Rotten/bowing floor joists. With moisture building up, wooden structures like rim joists and beams will soak up some of the moisture and start decaying. This winter moisture can end up weakening your subfloor and wooden supports. 

Insect infestation. Moisture makes the crawl space an attractive nesting place for insect, pests and vermin, including termites and other wood-destroying insects. 

Insulation damage. If your insulation is defective, evaporating moisture can collect on it and destroy it. 

Crawl space condensation. Many homes built on crawl space foundations experience condensation due to open vents and poor moisture management. 

How to Best Control Your Crawl Space Temperatures / Moisture? 

Many people have many opinions on this topic.  Generally, this is a topic where one answer doesn’t fit every situation.  It is best for you to make your own determination because you know your home and your climate the best.  Most people find it most beneficial to close their vents in the cold Winter months AND the hot Summer months.  You can put your Vanity Vents on in literally less than 3 seconds and they come off even faster.  Easy peasy.  Some customers leave their Vanity Vents on all year – of course they check each year to make sure everything is working fine.

The absolute easiest on/off crawl space vent cover on the market is Vanity Vents.

Recommended Crawl Space Vent Solution – Vanity Vents! 

Vents on the outside of the crawl space allow air, water, and pests into your home. You can prevent these nuisances with durable vent covers. Vanity Vents are built to last and you won’t need to repaint them or worry about rotting or rusting. They’re simply installed over existing your existing vents.  VERY IMPORTANT:  Please measure your vents before you order Vanity Vents!  

Are you ready to get smart about controlling the comfort level and weatherization of your home?  Get Vanity Vents today!