A homeowner applies window caulk to the bottom sill on a window's interior.

Air gaps in your home can cause a spike in your electricity bill, as your temperature control system will have to work much harder to maintain a comfortable living environment. Luckily, there’s no shortage of ways to prevent this, including caulking. 

Caulking windows saves energy by blocking cold air from getting into your home. It also prevents cold air from escaping your living space during the summer, keeping your house cooler. 

The following sections will discuss how window caulk saves energy in greater detail. We’ll also take you through how to effectively caulk windows to save energy and how long window caulk generally lasts. 

How Does Window Caulk Save Energy?

Caulking windows saves energy by affordably blocking airflow from leaving and entering a building. This process, in turn, means less energy is required to maintain a comfortable temperature, resulting in a lower electricity bill. You can save an average of 7-8% on your energy bills by caulking your windows.

Caulking also prevents excess moisture from entering your home.

If you’re wondering specifics on how much energy you can save by caulking your windows, you can save between 5% and 10% on each bill. So, it’s worth checking your home for air gaps and filling them as necessary if you want to save some money!

Now, let’s discuss the different ways window caulk saves energy in various weather conditions a bit more in-depth.

Caulking During Warm Summer Weather

During the warm summer months, you want your home to be as cool as possible. Unfortunately, this often ends up running up an expensive energy bill, which is why many strive to avoid having the AC on all the time. 

If you have air gaps in your home, the warm summer air will get in through the cracks. Additionally, the cooler air in your home will escape, making the internal temperature increase—this is when you’ll find yourself using the AC often.

By caulking your windows, warm external air won’t be able to get into your home, and the cool air inside can’t escape. 

The decrease in energy consumption that comes as a result will help you save on your electricity bill and be more environmentally sustainable.

Caulking During Cold Winter Weather

During winter, the main goal is to keep your home as warm as possible without using too much energy. Keeping your home warm will be much more challenging if you have air gaps.

As expected, openings in your home’s structure mean that the cold air from the outside will seep through the gaps, while the warmer air from inside will escape. 

If you caulk any gaps around your windows, you’ll prevent the warm air from leaving your home and cold air from getting in. This results in a lower energy bill and a more comfortable living space.

Caulking Prevents Moisture-Related Issues

Having air gaps in your home allows moisture from the outside to flow in. Unfortunately, this phenomenon can damage your home, as too much humidity can promote mold growth.

Additionally, it may cause your walls or ceilings (or both) to get excessively humid, which may result in water damage. One of the common ways to reduce moisture in a room is by using a dehumidifier. However, these devices are electrical, so they use energy.

To ensure you don’t need to resort to using dehumidifiers all over your home, you should consider caulking the gaps around your windows. 

How To Efficiently Caulk Windows To Save Energy

To efficiently caulk windows for energy saving, you should apply window caulk to any gaps found in your home’s structure. You can do this repair yourself using a caulking gun. 

Closeup on a homeowner applying window caulk to a seam at the base of a window's interior using a caulk gun

It’s essential to search high and low for any possible gaps to increase the chances of an efficient window caulk job. If you miss any holes, outside air will still be able to get in, and the indoor air will still be able to escape.

Now, let’s take a more in-depth look at how to caulk windows to save energy effectively.

Choose the Right Materials

The first step is to find suitable materials. Not using the right materials may hinder the results and may not even help save energy. 

The US Department of Energy recommends using weatherstripping material for all operable windows. However, for gaps that don’t move, you should use regular window caulk material. 

A caulk that works well for windows is the Gorilla White Sealant/Caulk. You can use this caulk indoors and outdoors, meaning you’ll be able to insulate the whole structure in one go. It also dries to a translucent white color, so it’s barely noticeable.

Here are some other materials you may need:

  • A scraper – you’ll need a scraper if there’s any old caulk leftover. 
  • A blade – you’ll need a blade to cut off the tip of the caulk container.
  • A long sharp object – you’ll need a long sharp object to pierce the seal of the caulk container (a nail, for example).

Find the Air Gaps

Locate all the air gaps around your windows before continuing. You may also want to fill in other gaps around your home.

If that’s the case, be sure to examine everywhere, as some cracks can be hard to find. Once you have found all the air gaps, you can begin the window caulk application.

Caulk Using a Caulk Gun

A caulk gun makes it easy to fill in air gaps around your window, so it’s the best thing to use for the job. 

A caulk gun and window caulk tube side by side

Before beginning, you’ll need to scrape away any loose paint or old caulk. Then, you must cut the tip of the caulk tube with a blade before piercing the film seal with a nail or other sharp object.

Once the caulk can exit the container freely, you can begin caulking. Be sure to get all the gaps by moving the gun carefully around the window.

To ensure your energy bills drop as low as possible, you should caulk both the outside and inside of your home for the best results.

For a quick tutorial on how to caulk windows, check out this YouTube video.

How Long Does Window Caulk Last?

Window caulk lasts between 5 and 10 years in most cases. However, the precise time can depend on the caulk used and environmental conditions. Nevertheless, since it generally lasts for years, it’s an easy and efficient way to reduce energy consumption.

Although your window caulk will likely last several years, you should still check it every year or two to ensure it’s still intact. 

Since caulk on the exterior of your windows generally lasts the same amount of time as exterior paint, you should consider redoing them both simultaneously.

Replace Caulk To Keep Saving Energy

You don’t need to redo a caulk job too often. However, as soon as you notice a gap or two, it’s crucial to take the proper measures as quickly as possible.

Replacing old window caulk as soon as it becomes a problem will ensure you keep saving money on your energy bills.

If you leave old caulk unretouched for too long, it’ll become inefficient, and you’ll have to use more energy to heat or cool your home. 

Knowing When To Replace Caulk

You now know the importance of redoing a caulk job when it begins wearing away, but how exactly do you know when to replace it?

The biggest indicator that the caulk needs to be replaced is if it rises and chips away. You’ll likely notice chunks coming off the same way old paint does.

window caulk at the bottom of a window's interior that has started separating from the seam

When chipping occurs, the uncovered gaps could lead to a multitude of issues, including mold and water damage. Water can get trapped between the caulk and the wall or window quicker than you’d think, so you want to be proactive.

What Happens if Windows Are Not Caulked?

If windows aren’t caulked, many issues can arise, including mold growth, water damage, increased energy consumption, and higher energy bills. Overall, caulking is environmentally and budget-friendly, so it’s best to caulk all windows if possible.

Additionally, most caulking materials are non-toxic. 

Now it’s time to take a deeper look at what can happen if windows are left uncaulked.

Mold Growth

Mold is undoubtedly an issue that any household would want to avoid. However, by keeping windows uncaulked, there’s a much higher chance of mold growth. 

When moist air gets in through the gaps, it can make your home’s interior excessively humid. Then, mold spores can interact with these wet surfaces, which causes them to grow.

Mold looks unappealing, but it’s also unhealthy to breathe in and can cause allergic reactions.

In short, even though caulking windows doesn’t guarantee that your home will be mold-free, keeping them uncaulked certainly increases the chances of mold growth.

Water Damage

Since air gaps can let moisture and water in from the outside, leaving them open can result in water damage. For example, if your window has air gaps, moisture can get through them and cause water damage to the surrounding walls or ceiling. 

Caulking your windows will help prevent water damage in your home.

Increased Energy Consumption

You’ll need to use more energy if your windows are not caulked, and household energy consumption is one of the leading causes of greenhouse gas emissions. 

Therefore, it’s essential to caulk your windows and ensure every air gap is adequately sealed to reduce emitting these harmful gasses.

Higher Energy Bills

As briefly mentioned, leaving windows uncaulked can significantly increase your energy bills. Having air gaps means you’ll regularly need to use gas or electricity to heat or cool your home.

You can save as much as 10% on energy bills by sealing air gaps around your windows and the rest of your home. 

Given how easy and DIY-able the caulking process is, there’s really no disadvantage to sealing your home’s air gaps.

How To Ventilate Your Home Without Wasting Energy

In this article, we’ve continuously mentioned how vital the caulking process is, as it helps reduce energy consumption by blocking external air from getting into your home. However, you shouldn’t forget the importance of ventilation, too.

Let’s look at different ways you can ventilate your home through your windows without running up a large energy bill:

  • Open windows in the evenings during the summer – the air at night will be cooler, so it should be okay to open windows once the sun begins to set. That way, you can get fresh air into your home without it getting too hot.
  • Open windows for short periods during the day in winter – avoid opening windows at night during winter, as this is when it’ll be the coldest. Of course, it’ll likely be cold during the day, too, but it’s essential to aerate your living space from time to time. Keeping windows open for as little as 20-30 minutes every day will significantly improve the air quality in your home without making it too cold.
  • Open windows when cooking – it’s also essential to open kitchen windows when cooking to allow all the steam and grease to escape. If you don’t open windows, these fumes and residue can cause grime buildup and mold in your home.

So, once you’ve caulked your windows, don’t forget to keep your home ventilated at the same time.


In conclusion, caulking windows is an excellent way to save energy and reduce your bills by up to 10%. It prevents outside air from getting in while also preventing internal air from getting out.

To caulk windows efficiently, you should fill in every noticeable gap around them. If you use a good quality caulk material and apply it correctly, it can last up to ten years.

Finally, while caulking windows reduces energy consumption, it’s still important to promote ventilation by opening windows from time to time.


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