FM Articles

Unit Heater Size: Why Does It Matter?


When the days become shorter and the temperatures start to fall, having the right heating solution is paramount for your facility. Whether it’s to keep your workers warm and comfortable or to protect precious equipment and supplies, heating units are necessary to maintain optimal conditions. However, finding the right unit for your facility can be difficult with so many options available.

According to Grand View Research, the global HVAC systems market size was valued at $136.3 billion in 2022 and is projected to grow at a compound annual growth rate of 6.3% from 2023 to 2030 with there being a gradual shift in focus to energy-efficient units. The same report states that as of 2022, the heating segment of the market captured over 28.2% share of the market.

With the options for heating solutions being vast, it’s not only important to pick the right type of solution, but it’s also important to pick one that is properly sized for your heating needs. For facilities that utilize a boiler system, selecting a unit that isn’t the right size for your facility could be detrimental to your potential energy savings and the unit.

Hydronic Unit Heaters and Boilers
A building’s central heating system plays a major role in determining the right solution for your facility. If your facility utilizes a boiler system, it’s important to find the right hydronic heating unit. Hydronic unit heaters provide facilities with a permanent heating source that ties into the boiler system. When supplying heat to a space, the unit extracts heat from the boiler’s hot water to deliver warm air to the area.

Hydronic unit heaters are also an optimal selection for facilities because of their relatively small size and easy installation. Thanks to their ability to be hung from the ceiling, these units can save floor space by being tucked away and out of sight while still providing an efficient heating source. For facilities, having sufficient floor space for operation can be critical, so unit heaters are a terrific choice.

Picking the Right Size
Now that you have found the right hydronic unit heater for your facility, it’s time to find the proper size for your heating needs. This is important because having a unit that is too big or too small can have adverse effects on a unit’s ability to warm the space.

Looking at the downside of having a unit that’s too small, this can create heat cycles that are long. As a result, the system may have trouble keeping up with heat demands once the colder months arrive. In addition, efficiency will suffer because the unit will be forced to run much longer because it’s trying to warm a space that is too large for it – increasing your energy consumption.

On the opposite side of the spectrum, having a unit that is too big for the space can also be detrimental to your facility. When the heating source is too large, it can result in the unit “short cycling” because the space is heating up too fast. This can also cause an issue with larger airflow because the unit will have a larger fan motor.

There are several factors that should be used when determining what size unit heater to select for your facility. Those include the desired temperature, the climate in the region, the size of the space and insulation. First, you must calculate the heat load by looking at the average outdoor temperature in the coldest months, the desired temperature, and the size of the building. After this is determined, facility managers can reach out to a contractor for recommendations on a properly sized hydronic unit heater.

Keep Your Facility Warm
Preparing your facilities for the fast-approaching winter months shouldn’t be a last-second process. Having the proper heating solution in place to create the desired atmosphere is a necessity. In addition, it’s just as important to have one that is properly sized for your building. This helps avoid the troubles associated with “short cycling” or prolonged energy consumption. When it comes to efficiently heating your facility, size matters!

Jamie Tuinstra is a product manager at Modine Manufacturing. He has been in the heating and cooling industry for 25 years and with Modine for 16. Building on more than 100 years of excellence in thermal management, we provide trusted systems and solutions that improve air quality and conserve natural resources. Modine is a global company headquartered in Racine, Wisconsin (USA), with operations in North America, South America, Europe and Asia. For more information about Modine, visit