Does insulation keep your house cool?

Author: Tessie Tromp  |  Last update: Saturday, December 27, 2025

The short answer, yes, insulating the attic is an effective way to keep your home cooler during the summer months. While it's a given that the insulation in your attic will keep the home warmer during the winter, it isn't immediately obvious that insulation can also help to keep the home comfortable during the summer.

How much cooler does insulation make a house?

How many degrees of difference insulation makes on its own depends on the type of home you have, what the weather is like and what kind of insulation you have. Depending on what you choose, you could see a five- to 20-degree temperature difference just based on the insulation alone.

Does insulation affect air conditioning?

Increased AC wear and tear: The hot air that enters your home due to poor attic insulation increases the strain on your air conditioning system, leading to increased wear and tear, more frequent breakdowns, and costly repairs.

Why is my house colder after insulation?

Even with new insulation, your home might feel cold due to air leaks and drafts around windows, doors, and vents. A reason can be gaps or compression in insulation can limit its effectiveness, diminishing thermal resistance.

Does cavity wall insulation make a house cooler in summer?

Cavity insulation will help keep the house cool in the summer (as well as keeping it warm in winter) because the sun is overhead in the summer and the roof is a major path of heat gain. Cavity insulation will help block this heat gain from attic to inside.

How to keep your house cool in the summer without AC

Why is my house so cold even with cavity wall insulation?

This is another symptom of your cavity wall insulation's deteriorating health. Your boiler and radiators are working overtime to try and warm your house up, the heat wants to escape, and your insulation is allowing it! If your insulation can't even hold itself up, then there's no chance of it holding your heat in.

Why are people removing cavity wall insulation?

One of the main reasons as to why people decide to have their cavity wall insulation removed is because their property isn't suitable for it. For instance, if your property is often subject to wind-driven rain, then it is not recommended that a cavity wall is in place.

Does new insulation help keep house cool?

Insulation plays a big role in controlling the transfer of heat into your home. It keeps your home cooler by blocking outside heat from seeping in through walls, ceilings, and roofs.

Why does my house feel cold at 73?

If you're cold even though your thermostat indicates you shouldn't be, your furnace likely isn't the problem. In most cases, it's working just fine. It's your home that needs attention. Lack of insulation, severe air leakage, and/or unbalanced ductwork are frequently to blame.

Why is my house so cold even in summer?

A common reason for a cold house is often insufficient insulation. Insulation serves as a barrier, preventing heat from escaping and cold air from entering. In homes with inadequate insulation, this thermal barrier is compromised, resulting in heat loss and difficulty retaining warmth.

Does insulation make it cooler in summer?

Insulation helps keep your home warm in winter, but it also keeps it cool during summer. A properly insulated house stays cooler for longer in summer and warmer for longer in winter and uses less energy to keep at your desired temperature. This leads to a more energy-efficient house and savings on your power bill.

How much does insulation help with air conditioning?

According to the U.S. Department of Energy, proper insulation can reduce heating and cooling costs by up to 20%. This can result in significant savings on energy bills, making it a worthwhile investment.

What happens if your house is not insulated?

The lack of insulation in homes can lead to condensation and mould growth, creating unhealthy living environments and potentially causing structural damage. Insulation slows the movement of heat through the walls, roof, and floors, maintaining a more consistent indoor temperature.

Can you put too much insulation in a house?

It is possible to over-insulate your house so much that it can't breathe. The whole point of home insulation is to tightly seal your home's interior. But if it becomes too tightly sealed with too many layers of insulation, moisture can get trapped inside those layers. That's when mold starts to grow.

What happens if your house is too hot?

“Pipes can expand in high temperatures, leading to leaks or even bursts, especially in older systems. And when it comes to electricity, the increased power consumption during hot spells can overload your system, potentially causing circuit issues or, in worst-case scenarios, electrical fires.”

Are 90% of homes under insulated?

Based on new research, the North American Insulation Manufacturers Association (NAIMA) estimates that roughly 90% of existing U.S. homes are under-insulated. That means that the occupants are less comfortable, and both energy and money are being wasted.

Is 74 too hot for a house in summer?

The recommended thermostat setting for summer is 72 to 78 degrees. On long, hot summer days it's tempting to push your air conditioning to the max — but be careful. Heating and cooling typically makes up the largest energy expenditures in a household.

Why am I hot but my house is cold?

Rooms Are Cold Even With Heating On

This problem often points to inadequate circulation of warm air. It could be due to blocked vents, a failing HVAC fan, or issues with the furnace itself. Ensure that furniture or drapes are not blocking your vents.

Is 78 too hot for a house?

Whenever you're not at home or are asleep, consider increasing the temperature to between 78 and 80 degrees for even further savings. It's advisable to keep your home below 80 degrees throughout the summer. A house that's too warm can be dangerous to people, pets, and the soft surfaces in your home.

How often should a house be re insulated?

Most forms of insulation can last for decades under ideal conditions. However, various issues inside your home can make retrofitting or replacement necessary much sooner. Some homes have the original insulation for upwards of a century, while others may require upgraded insulation in as little as 15 years.

What insulation keeps rooms cool?

Highly reflective foils in radiant barriers and reflective insulation systems reflect radiant heat away from living spaces, making them particularly useful in cooling climates. Other less common materials such as cementitious and phenolic foams and perlite are also available.

How do you keep a poorly insulated house cool?

How to Keep Your House Cool Without A/C
  1. Invest in the Right Ceiling Fans. ...
  2. Optimize the Fans You Have. ...
  3. Flush Out Hot Air in the Evening. ...
  4. Update Your Insulation. ...
  5. Weatherize Your Windows and Doors. ...
  6. Switch to No-Heat Lightbulbs. ...
  7. Install a Whole-House Fan. ...
  8. Create a Crosswind With Multiple Fans.

What is the downside to cavity wall insulation?

This means that there will be a moisture build up in your walls. The moisture will transfer to your cavity insulation, and damp and mould will begin to develop inside your walls. This really does become a hindrance for you when the mould starts growing inside your home, and damages your things.

How much does it cost to remove old insulation?

Expect costs of between $1 and $2 per square foot to remove insulation, with blown-in varieties near the lower end and rigid types near the top end. Keep in mind that those prices are for dry and in good condition non-asbestos insulation.

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