Garage Humidity is Destroying Your Tools and Electronics

I think everyone can agree that humidity makes US miserable. Heat is bad enough by itself, but humidity makes everything that much more miserable.

But how bad is it for the stuff you store in your garage?

As it turns out…pretty bad.

One of the reasons that humidity is so damaging in your garage is that your garage is home to your tools, personal items, exercise equipment, toys and (of course) your car.  

Does humidity affect tools and electronics? Tools and vehicles that are constantly exposed to high humidity levels can be at risk for rust. Electronics, even those that are water resistant, can be damaged by high humidity levels in your garage.

In addition, personal items can be damaged or even destroyed by humidity if not stored in air-tight containers. Papers, cardboard boxes, and fabrics are easy targets for mold and mildew.

I’m going to get a little sciencey in this article, because I think it’s important to show that this isn’t just my opinion. There are facts to back this up.

If you don’t care about the science, feel free to skip down to the section titled “Summary” to see the summary and some recommendations.

But if you’re still on board, let’s keep going.

Humidity is bad for your tools

Water and metal don’t mix. Got it. We’ve all seen rusty steel tools before, so this shouldn’t be a surprise.

Fair point, but hang on a second because it’s worse than you think…

Did you know that stainless steel can rust?

I didn’t.

To make steel ‘stainless’, additional metals are added to the mix. Some of these, like Chromium, help make the metal resistant to rust, but it’s still possible.

Cougartron, which is a US-based company that makes stainless steel coatings, sets the record straight:

“The reality is that stainless steel does rust. The word “stain-less” does not imply free from stain or “stain-impossible”. It simply means that the alloy stains less.”

Given the right set of circumstances, any metal can rust or corrode – even in your garage. It’s important to keep moisture and humidity under control if we want to make our tools last as long as possible.

Humidity is bad for electronics

This makes sense, right? Water and electricity don’t mix.

When I say “electronics”, I mean literally anything with circuitry or wiring.

So this would include big things like your garage TV, a sound system or speakers that you keep in your garage, or any exercise equipment that you store or use there.

It also includes any power tools that you keep in your garage or your classic car sitting under a car cover.

Now do I have your attention?

The challenge is that even electronics that are designed to be water-resistant are still exposed to the air. If humid air can get in, it can bring water vapor with it.

Water-resistant and water-vapor resistant are NOT the same thing.

When water vapor in the air cools down, it changes back into a liquid. This is how we get dew on grass in the morning, or frost in the winter.

Semikron, one of the largest semiconductor manufacturers in the world, released a study on the effects of humidity and condensation on electronics back in 2016. (link to pdf)

They found that condensation poses a more serious threat to electronics because the water molecules are attracted to the electrically-charged circuits inside the devices.

As they put it: “the resulting failures from these effects are usually catastrophic and it can be very difficult to identify humidity as the root cause.”

In this case, an ounce of prevention is worth a lot more than a pound of cure.

Condensation breaks down lubrication

We’ve all heard the saying that oil and water don’t mix. That also applies to any lubricants that you may be using in your garage as well.

One key element in maintaining our tools and lawn mowers is lubricating any moving parts with some sort of oil.

When water vapor (in the form of humid air) condenses and turns into liquid water, it eventually starts to break down any oils that it comes into contact with.

We all know how destructive it can be when sand or metal shavings get into your gearbox.

Consider what J. C. Fitch and Simeon Jaggernauth said in their paper on the effects of moisture on machinery:

“Moisture is generally referred to as a chemical contaminant when suspended in lubricating oils. Its destructive effects in bearing applications can reach or exceed that of particle contamination.”

According to their study, moisture can be as damaging – or MORE DAMAGING – than any physical particle rattling around in your gearbox.

Summary (for those that skipped ahead)

So we learned that a high amount of water vapor in the air is the same thing as a high relative humidity level. That water vapor will eventually condense back into liquid water and start destroying our tools, electronics and any lubricants we use on our machinery and tools.

So what do we do about it?

High humidity in your garage
This is far too much humidity in your garage

The obvious lesson here is to try to control the humidity level in your garage.

Here are seven tips that I recommend:

1. Use a Dehumidifier

This is the most effective (and cheapest) option. Most dehumidifiers are less than $200 and can lower the humidity level in your garage and keep it there. For my recommendation on what I consider the best garage dehumidifier, check out my detailed article.

2. Moisture absorbers are quick fixes

A lower cost option would be to use a moisture absorber like Damprid. They’re commonly found for around $5 each and last for about 45 days. They’re not a long-term solution, but they’re a great option if you only have a few high-humidity days each year.

3. Seal your garage door and windows

Try to make your garage as air-tight and water-tight as possible. This means replacing any damaged seals around windows (if you have them) and your garage door. Also look at a garage door threshold seal to act as a water barrier and keep moisture out of your garage.

4. Increase air-flow with a fan

Any kind of air flow in your garage will help spread out the humid air to other parts of the room. It’s not a perfect solution, since it still relies on that air going somewhere. If the entire garage is filled with humid air, just moving it about won’t help. But the thought is that a good garage fan circulating the air towards an open window or exhaust fan will help lower the overall humidity in the room.

5. Seal your concrete floor

Did you know concrete sweats?

Concrete is a very porous substance, meaning it absorbs water extremely well. Unfortunately that works both ways. When you see beads of water on the surface of your concrete floor, that’s called concrete sweating. A great way to fix this (and also stop that moisture from evaporating into the air) is to seal or epoxy your bare concrete floor.

6. Waterproof your concrete walls

If you have bare cinder block walls, it’s a good idea to paint them with a water-repelling paint. I used Drylok to paint my concrete garage walls to add an extra layer of protection and keep any moisture outside where it belongs.

7. Air conditioning

The best solution is (of course) the most expensive. Installing an air conditioner in your garage will help keep the relative humidity level low. Portable air conditioners start at around $300 and go up to around $1K for a mini-split air conditioner.


Like I said at the beginning, humidity can be catastrophic for your stuff.

When relative humidity levels stay over 50% for extended periods of time, it becomes a breeding ground for mold and mildew. Condensation can form on your metal tools and inside your electronic components.

Eventually that moisture damages everything it touches, so it’s a good idea to take precautions and lower the humidity levels in our garages.