Contrary to what you have been told in the past, in the Pacific Northwest, leaving crawl space vents open in summer can actually create moisture problems in your crawl space instead of preventing them.

Why?  Because warm air holds more moisture than cool air ( the moisture is called humidity – you have heard of it). When the warm air enters your crawl space and meets the slightly cooler air, moisture is produced.  This moisture can lead to mold, mildew and other problems.

In terms of fundamental thermodynamics, heat follows cold—meaning warmer air, being less dense, moves toward cold air and eventually warms the colder air. When your crawl space vent is open and it is warm outside but cooler in your crawl space, the warm air will enter (follow) your crawl space vent and heat the air under your home.

The warm air is humid.

Your crawl space is usually slightly cooler than the outside air in the Summer (because it is shaded and partly underground, i.e., in your crawl space).

When the warm air enters (follows) your crawl space it cools down, it can’t hold as much moisture. The excess moisture condenses on cooler surfaces like wood framing, pipes, and insulation and can create mold and/or mildew.

That process is basically the same physics behind condensation on a cold drink when it is sitting outdoors in the warm summer.  Eventually, your glass of cold beverage will sweat, resulting in excess moisture on the outside of the glass.

This is what happens when you keep your foundation vents open in the Summer – the warm air enters your crawl space and meets the cooler air in your crawl space… the end result is the creation of excess moisture in your crawl space.

You do not want excess moisture in your crawl space.

Excess moisture in your crawl space:

When you close foundation vents in summer:

  • You reduce the amount of humid outside coming into your crawl space
  • Humidity (moisture) levels stay more stable inside your home resulting in more interior home comfort for you and your family
  • Critters are kept out of your crawl space… they can be a big problem all by themselves. Ask anyone who has had a family of racoons move into their crawl space.

In the Pacific Northwest, where summers are mild but you can still have humidity swings, closing vents during warmer months often reduces this condensation risk.

If you have the money, one alternative is to seal/encapsulate your entire crawl space.

Crawl space encapsulation is the process of sealing a home’s under-floor area from the outside environment using heavy-duty polyethylene plastic, or vapor barriers, on walls and floors. It often includes sealing your crawl space vents, installing a dehumidifier, and even adding sump pumps to turn your damp crawl space into a dry, conditioned space.

The problem with encapsulating your crawl space is the cost $$$.  A typical cost is about $23,000 for a 2,000 square foot home. Ouch!

A fantastic, inexpensive, long-term alternative to encapsulation are Vanity Vents Crawl Space Vent Covers. Vanity Vents allow you to seal your crawl space vent openings. Vanity Vents save you money, keep the interior of your home comfortable, all while creating instant curb appeal for your home!

With Vanity Vents, you can insulate your home, save on heating and cooling bills, and minimize crawl space dampness in three seconds – all while boosting your home’s curb appeal. Open foundation crawl spaces are inefficient, unappealing, and attract moisture. In the winter, cold air fills the space beneath your home. As a result, your heating system must work double-time to keep your home comfortable. In summer, your crawl space becomes a heating pad, and your air conditioner is forced to work harder than necessary. Both these scenarios have the same result: skyrocketing energy bills.

Vanity Vents can fix these problems for you almost instantly… usually for as long as you live in the home.

The only real alternative to Vanity Vents is the styrofoam crawl space vent inserts that every homeowner loves to hate – lol.  In a very short time the styrofoam crumbles, gets dirty, and look messy. That’s where Vanity Vents come in. Vanity Vents are long-lasting, USA-made home weatherization solutions that pay for themselves in energy savings. They are robust and do not bend, break, or warp.

If you already have the Styrofoam vent inserts you can prolong their life at least a little bit by covering them with Vanity Vents Vent Covers.

The best option for almost every home (short of paying $20,000+ for encapsulation) it the Vanity Vents Combo Pack… a combination of Vanity Vents Vent Covers and their Vanity Vents Insulation Blocks. This gives you two times the crawl space insulation.

Designed with the most discerning homeowners in mind, Vanity Vents crawl space vent covers and insulation blocks are practical, innovative, and gorgeous. Install yours in just three seconds – no tools required.

Please note: You must measure your vent opening before ordering to determine if you need the Standard Size or the Custom Large Size solution. Also, please note that your vent opening must have a vertical center panel in the middle of your crawl space vent for Vanity Vents to work.  Vanity Vents products only work in Oregon, Washington and Idaho.

If you are the kind of person who likes to save money on utility bills while having the most beautiful home on the block then visit vanityvents.com

With nearly 100% 5 Star Ratings on Google, you cannot go wrong.

Please call or text if you have any questions or if we may be of any further assistance.

Back