Why is my Basement Hot in the Summer?

build in wall unit and luxury staircase in basement remodeling project vaughan

If you’re like most homeowners, your basement is one of the coolest places in your house during the summer. However, if you’ve been noticing that your basement has been unusually hot lately, there may be a problem with your cooling system.

In this blog post, we’ll discuss some of the possible causes of a hot basement and how you can address them. We’ll also provide some tips for keeping your basement cool during the summer. Keep reading to learn more!

Hire a Professional

If you find yourself wondering why is my basement humid in the summer, there are a few different factors at play. One common cause is poor ventilation. If your basement is not well-ventilated, the air will become stagnant and humid. This can be a problem in both summer and winter, but it’s especially noticeable in the summertime when the air is already warm and muggy.

Another possible cause of basement humidity is a leaking water heater. If your water heater is leaking, the water will evaporate and add moisture to the air. This can also lead to mold and mildew growth, which can be a health hazard.

Finally, if your home has a sump pump, it may be causing your basement humidity problems. Sump pumps are designed to remove water from the basement, but if they’re not working properly, they can actually add moisture to the air. This is because the pump will evaporate the water as it tries to remove it from the basement.

Modern Family Room in Basement Renovation Project Woodbridge

How Does Moisture Get into the Basement?

There are a few different ways that moisture can make your basement humid. One common way is through the foundation. Foundation cracks can allow water to seep into the basement, and this water will add moisture to the air.

Another way that moisture can get into the basement is through condensation.

This can happen if the temperature in the basement is lower than the temperature in the rest of the house. When warm air hits a cold surface, it will condense and form water droplets. This can happen on the walls, floors, or ceilings of the basement.

Finally, moisture can also enter the basement through evaporation, making your basement humid in summer. This can be caused by several things, including a leaky water heater, a humidifier, or even just the humidity in the air.

How to Control Basement Humidity in Summer

If your basement is hot in the summer, try the following techniques to reduce humidity:

Amazing Basement Kitchen Design Woodbridge


One of the best ways to control basement humidity is with a dehumidifier. Dehumidifiers work by removing moisture from the air. If you don’t have a dehumidifier, you can also try using a fan. Fans will help circulate the air and prevent the air from becoming stagnant. You can also reduce basement humidity by opening windows and doors. This will allow fresh air to circulate and will help to remove moisture from the air. Finally, you can also try using dehumidifying paint on your walls. This type of paint is designed to absorb moisture, acting as a sort of dehumidification method.

Interior drainage 

Another way to reduce basement humidity is to install an interior drainage system. This will collect water that seeps into the basement and redirects it to a sump pump. The sump pump will then remove the water from the basement, which will help to reduce humidity levels. You can also try using exterior drainage to help manage the humidity in the basement. This involves installing a drainage system around the perimeter of your home. This will collect water before it has a chance to seep into the basement. Finally, you can also try waterproofing your basement. Waterproofing will help to prevent water from seeping into the basement.

Seal foundation cracks

If you have cracks in your foundation, water can seep into the basement and add moisture to the air. To reduce basement humidity, you’ll need to seal these cracks. You can do this yourself with a concrete sealer, or you can hire a professional to do it for you. You should also check for cracks in your walls and floors. These cracks can also allow water to seep into the basement, so it’s important to seal them as well.

Basement Renovations Stouffville

Leave windows shut

In the summer, you’ll want to leave your windows shut as often as possible to prevent hot, humid air from entering the basement. If necessary – and as noted above – it may be beneficial to open them a few hours each day to allow fresh air circulation, however, be wary of leaving them open too long as it will lead to increased chances of temperatures rising.

Don’t irrigate the garden

If you have a garden, you’ll need to be careful about how you water it. If you water the garden too close to the house, the water can seep into the basement and add moisture to the air. To prevent this from happening, you should water the garden in the morning so that the sun can evaporate the water before it has a chance to seep into the basement. You should also avoid using a sprinkler system. Sprinklers can also add moisture to the air, so it’s best to avoid them if possible.

Small Basement Music Room Design Stouffville

Grade the yard

One of the best ways to prevent water from seeping into the basement is to grade the yard so that it slopes away from the house. This will ensure that water drains away from the foundation and doesn’t have a chance to seep in.

Maintain gutters and downspouts

One final way of maintaining basement temperatures in the summer is by ensuring that your gutters and downspouts are in good working order. If they’re not, water can build up around the foundation and seep into the basement. Clogged gutters can cause water to back up and seep, making it very important to keep them clean on an ongoing basis.

A Humid Basement Solution

If you find yourself wondering why is my basement hot in the summer, there are a few potential causes, most notably, improper ventilation, excess moisture in the air, and cracks in the foundation. In order to reduce basement humidity, homeowners should invest in more effective ventilation, install an interior drainage system, or waterproof their basement.

It’s the middle of July so why is my basement hot? Contact Harmony Basements to help with your summer woes. We’re a team of basement experts – helping clients with renovations, maintenance, and everything in-between for years. Reach out to our professionals today to learn more about our team, and services, or to request a project quote!