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How Long Does It Take to Insulate a House? (Quick Answers)

Are you thinking about insulating your house but don’t know how long it can take? It can get pretty confusing as there are many things to determine. This article will discuss all the factors that affect installing time and things you should know before installing insulation in your house.

How long does it take to insulate a house?

The installation process can take about 5-12 hours, but other things can affect the time. If you need to remove the old insulation, you will need an extra day. Insulation material, experience, size of your house, and other factors can affect insulation time.

Insulating your house is something you must not do in a rush, as it will protect you and your home from the harsh temperature and make your house livable. Sound insulation is also essential for saving energy. If the temperature is leaking, you are wasting energy.

Why is it so essential to be careful? Small mistakes in the insulation process can make your house like a bucket with a hole. If you don’t install insulation properly, you will not get the maximum from your insulation. 

Moreover, once the insulation is set, it’s pretty hard to find out where the temperature is leaking.

But don’t worry. You will have all the necessary information and guidance about insulating your house by the end of this article. Now, let’s focus on the timeline of insulating a house.

The installation process can take 5-12 hours on average. But it is different between a new house and an old house. Installing insulation in a new house is more manageable and needs less time. On the other hand, an old house may need twice as much time to install insulation.

Are you thinking of DIY your house insulation? A professional insulation agency will complete the process within the least time. Naturally, you will need a lot more time to cover all the areas of your house as you don’t have enough experience. 

We are not demotivating the DIY, but it will need more time. Also, you should do some research to learn the proper way to install insulation by yourself. 

You must be careful as a properly installed insulation can protect you from cold and heat for 10-80 years, depending on the material you choose.

The size of your house does matter. A bigger home will take longer to add insulation. While if you have a smaller place, you can expect to cover all the areas within one day.

No house is similar. There are parts of the house that are harder to add insulation. Such as attics take a lot more time compared to the walls. If your home has large places that are hard to add insulation, you will need more time to complete the installation process.

We will discuss those factors in detail in the latter part of this article. Now, let’s compare the installation time difference between an existing house and a new house. 

Existing house: 

If you want to remove the insulation of your existing house and then apply new insulation, you will need more time. The removal process usually takes one day at least. And the installation process will take about 5-12 hours, depending on your house size and other factors.

New house: 

A new house will take 6-12 hours to add insulation. It’s easier to insulate a new home as you don’t need to undergo the removal and cleaning process.

How long does it take to insulate with Sprayfoam?

Spray foam insulation takes 2-5 hours to cover a small to a mid-sized house. Spray foam takes less time to apply, but it takes the most time if you count the overall time. 

After applying the spray foam insulation, you can’t stay in the house for at least 24 hours. Newly applied spray foam has an odor, and the chemicals can be harmful to human health. For sensitive people, the issue can be more crucial.

So, it’s essential to stay away from your house for at least 24 hours. It’s best to stay away from home for 72 hours, but you can stay in the place after 24 hours without any significant risks. 

If there are children and older adults in the house, it’s recommended to keep them away for 72 hours.

So, as you can see, spray foam is quite a hustle, and it is pretty costly too. But considering its benefits, it’s more than worth it to take the hustle. Spray foam is the best insulating option, and it can last over 80 years if properly installed.

4 factors that determine insulation time of a house

Some factors can affect the installation time of your home. The necessary time for installing insulation depends on the following factors.

The size of your house:

The size of your house plays a significant role in the installation time. It can take up to twelve hours to insulate a large double storied home. It’s possible to wrap up a small house within 3-6 hours in general. 

Read the other factors to get a good idea about the timeline.

Hard to work areas:

Some areas are difficult and time-consuming to install insulation. Attics and the basement need more time than other places in a house. If your home has a large basement and attics, you will need more time to install insulation. 

Sometimes one may need a whole day to cover all the areas of an attic.


If you choose DIY methods to insulate your house, you may need over 40-50% more time to cover your home with insulation. Professional insulating services also have a minimum chance of making mistakes.

Insulating materials:

There are two types of insulating materials, and both take a different amount of time to install. The spray foam needs less time to install, while the radiant barrier takes more time. 

A radiant barrier is more suitable for DIY projects and also less costly. But it only lasts for ten years.

How much does it cost to insulate an existing house?

It can cost between $1.50 to $5.00 per square foot. If you have a house of 3,000 square feet, the cost will be between $4,500 to $ 15,000, depending on the material you choose and other factors. 

If you hire professionals and need to remove the old insulation from an existing house, you will have to spend at least $1 for every square foot. You can save quite a lot by doing it by yourself, but if you choose to DIY,  you must be ready to work hard patiently. 

Check out the DIY guide to the installation process in the following part.

What is the proper way to insulate a house?

Learning to apply the insulation process is not a 10-minute task. You need to research for multiple hours to understand what to do and what not to do. Different types of insulating materials involve different installation methods. 

Different materials have their pros and cons, and you should learn them all to choose the best one for you. You will have to go through R values and other required information that needs some time to absorb. Let’s talk about the proper steps of insulating a house with spray foam.


There are various brands of spray foam, and they can have different instructions that you should know. So, first, read them carefully.

Prepare the instruments:

Prepare the instruments you will need for the job. Wear a respirator, protective glasses, hand gloves and protective clothes.

Cover the area:

Cover the area around where you will add insulation.

Start spraying:

Start spraying the foam and find out a good rhythm and pattern. Spray ¾ of the total height of spray foam, the foam will expand the rest. 

Be careful:

Be extra careful while spraying foam near electrical outlets, doors, dryers, heat, air vents etc. Keep in mind that the foam is highly flammable. 

If you over apply foam in a place, you can cut off the extra foam after drying.

How long does it take to finish a house after insulation?

Some insulation does not require extra time after the insulation process, but spray foam insulation needs at least 24 hours before you can stay in the house. Read the instructions for more accurate information.

Spray foam can contain toxic fumes that can cause respiratory problems. But after 24 hours, the harmful effect reduces dramatically, and after 72 hours, the effects go entirely away.

Final Thoughts

One day is enough to install insulation in a small to mid-sized house. A larger home or a place with a larger basement or attic may need two days to add insulation. Spray foam takes less time, but you can’t stay in the house for at least 24 hours after installation.