Last Updated on February 16, 2026

Cold weather can slow a jobsite down fast. Freezing temperatures can delay schedules, damage materials and make it hard for crews to stay comfortable and productive. Concrete may not cure properly, paint can fail and frozen ground can stop work altogether.

The good news is that the right jobsite heater can help prevent these problems. This article will help you understand how to choose the right size and type of heater for winter projects. With the right heating solution in place, you can protect your materials, support your crew, and keep work moving safely and efficiently all winter long.

The Importance of Proper Jobsite Heating

Proper jobsite heating is more than a convenience during winter. It is a smart investment that helps protect your workers from cold stress and the project from costly setbacks. Many construction materials are sensitive to temperature changes. Concrete needs consistent warmth to cure correctly, while paint, drywall and adhesives can crack, peel or fail when exposed to freezing conditions.

Heating also plays a major role in worker safety and productivity. Cold crews tire faster, lose dexterity and face higher risks of cold-related injuries.

In addition, construction site heating keeps the ground from freezing, which is critical for excavation, grading and concrete placement. Without proper heat, winter conditions can bring work to a standstill.

Critical Jobsite Heater Safety and Guidelines

Portable heating solutions are a must-have for any construction site in cold weather. Many local and industry safety regulations require temporary heating for maintaining a safe project site and working conditions. But temporary heaters aren’t without their risks, primarily those associated with fire and toxic gas (carbon monoxide) exposure.

Before choosing or using a temporary heater, review all local and OSHA regulations and educate your teams. They need to know how to maintain safety when working with or near a portable heater.

For example, fuel-powered heaters, like direct fired and indirect fired heaters, need to have proper ventilation or ducting to remove exhaust fumes and carbon monoxide buildup. Electric heaters do not need ventilation, but the generators used to power them might.

Similarly, there needs to be a safe zone around the heater to minimize trip hazards and overheating nearby objects. The high heat these machines emit can ignite flammable materials or pose a burn risk to workers and sensitive supplies.

Learn More: 6 Safety Tips for Using Temporary Heating

What Size Heater Do You Need for Your Site?

Choosing the right size heater starts with understanding how much heat your jobsite needs and where the temporary heating equipment will be located. Using a heater that is too small will not keep the space warm, while one that is too large can waste fuel and increase costs.

When people talk about heater sizes, they’re often talking about more than the unit’s height and width. Heater size is also measured in BTUs, or British Thermal Units.

BTUs indicate how much heat the temporary heater will produce. The more BTUs, the more heat it produces.

To figure out how many BTUs you’ll need, and what size heater is right for your project site, use a BTU calculator or simply follow these steps.

1. Find the Total Cubic Feet of Your Space

The first number you need in order to calculate the total BTU is the volume of the area you want to heat up. The volume is also known as the total cubic feet.   

Calculate the cubic feet of the area you want to heat by multiplying the length, width and height of the space. For example, if a room is 10 feet wide by 10 feet long with 10-foot ceilings, the cubic feet is 1,000 ft³.

2. Decide on the Desired Temperature Rise

Next, you need to calculate the desired temperature rise. To do this, simply decide how much warmer you want the space to be compared to the outside temperature.

For example, if it is 30°F outside and you want the space at 60°F, your temperature rise is 30 degrees.

3. Determine the Insulation Factor

The last number you need before you can calculate total BTUs is the insulation factor. The insulation factor accounts for how well the space holds heat. This factor is simply an estimate, and there are generally three different insulation factors to choose from.

• For an average structure with some insulation, use an insulation factor of 1.0.
• For poorly insulated buildings or outdoor spaces, use an insulation factor of 2.0.
• For well-insulated buildings, use an insulation factor of 0.5.

4. Calculate the Total BTUs You’ll Need

Now that you have the total cubic feet, desired temperature rise and the insulation factor, you’re ready to calculate the total BTUs.

A simple way to estimate your BTU needs is with this basic formula:

Total Cubic Feet × Desired Temperature Rise × Insulation Factor = Total BTUs

Using the examples above, for a building under construction that’s not insulated yet, the total BTUs needed would be 60,000 BTU.

Example: 1,000 ft³ × 30 degrees × 2.0 insulation factor = 60,000 BTU

5. Consider the Site Layout and Workflow

You can narrow down your choices quite a bit once you know how many BTUs are needed. However, to make a final decision on the right size of heater, you also must consider the site’s layout, ventilation and how people will use the space.

How you answer the questions below will help you and your equipment rental provider determine which size(s) and type(s) of heater will work best.

• Is the site well-ventilated? You may need to place the heater and its generator outside, or add ventilation, to minimize the risk of carbon monoxide poisoning. Interior spaces may need an electric heater, which does not produce any exhaust.
• Is there enough room to maintain a safe distance between the heater and sensitive materials? Check all safety regulations and manufacturer requirements to make sure you can fit the heater safely in the space.
• Will the heater be able to heat the room adequately without getting in people’s way? Large, powerful heaters may take up too much floor space or be too loud for some spaces. Instead, placing multiple smaller units may be a better way to get the BTUs you need. 

Comparing Different Types of Construction Heaters

There are many types of heaters available, and each type comes in different sizes and total BTUs. The most common construction heaters are direct fired, indirect fired, and electric. Each type works best in specific conditions.

Direct Fired Heaters

Direct fired heaters burn fuel to create an open flame. The open flame heats the air, which is then blown directly into the workspace. Because the flame contacts the air directly, these heaters are very efficient and provide quick, powerful heat.

While they are nearly 100 percent fuel-efficient, they are not suitable for enclosed or occupied indoor spaces. This is because they run on propane or natural gas and, as such, produce exhaust that contains carbon monoxide. Since exhaust is released into the heated space, strong ventilation is required.

Best For: Direct fired heaters are best for open or well-ventilated areas such as outdoor construction frames, warehouses or large workshops.

Indirect Fired Heaters

Indirect fired heaters, like direct fired ones, run on propane or diesel. However, they separate the flame from the heated air. Instead, the burner heats a sealed combustion chamber and clean air passes over it, which warms the air. Then, indirect heaters duct the clean, warm air into the workspace and vent harmful exhaust outside.

These heaters are commonly used for interior construction, temporary enclosures and areas with limited airflow. Indirect fired heaters provide clean, safe heat when proper venting is used.

Best For: Indirect fired heaters are ideal for enclosed areas or jobsites where people are working for long periods.

Learn More: What Is the Difference Between Direct and Indirect Fired Heaters?

Electric Heaters

Electric heaters use heating coils and fans to produce dry, exhaust-free heat. Since they run on electricity, they are simple to operate and do not create exhaust. Simply plug it in and turn it on.

Electric heaters do not require ventilation, making them the safest indoor option. However, electric heaters usually provide less heat than fuel-powered models and require access to adequate electrical power.

If the project site is not yet powered by an electrical grid, then you’ll need a generator to operate an electric heater. The generator will produce exhaust, so the generator needs to be placed outdoors to keep the worksite’s air safe and clean.

Best For: Electric heaters are best for smaller enclosed areas, finished spaces or sites where fuel fumes or moist air are not allowed.

Learn More: Heat Cold Spaces Quickly, Efficiently and Safely with Portable Electric Heaters

Benefits of Renting vs. Buying Temporary Heating Solutions

For many contractors, renting temporary heaters is the most practical choice. Renting eliminates maintenance and storage concerns, since the equipment is returned after the job is complete. It also allows you to choose the exact heater size and type needed for each project, instead of relying on one unit for every situation.

Renting is often more cost-effective for short-term or seasonal heating needs. Reliable, high-quality rental providers also offer valuable time-saving services such as delivery, setup support, and quick repairs and maintenance, helping you get the right solution without added stress.

Buying a temporary heater usually only makes sense for companies with a constant and predictable heating need over a long period of time. For example, if the same size and type of heater is used year-round, then ownership could be cost-effective in the long run. For most projects, though, renting offers greater flexibility to adapt to changing needs and fast-paced projects.