Exploring Modular Building HVAC Systems
In the process of constructing a new modular office, classroom, or any other modular building, you’ll need to make decisions about incorporating an HVAC system. Modular building HVAC systems are responsible for heating, cooling, and distributing air through the entire space. These operations account for over 25% of a building’s energy use, so making wise decisions about the system you choose for your modular construction project has the potential for big savings in energy costs.
How HVAC Systems Work
If you’re unfamiliar with modular HVAC systems, here’s how they work:
- HVAC systems are designed to tie directly into a modular building’s ductwork.
- Warm air is drawn out from the building, cooled through a cooling coil, and redistributed back into the building.
- HVAC systems utilize economizers that pull in cool outdoor air and reduce the need for mechanical cooling operations.
- Outside air is harnessed for better ventilation and fresher air.
Choosing an HVAC System for Your Modular Building
When you’re choosing a modular HVAC system for your new construction, consider these elements of each option.
Humidity control — In addition to stable temperatures, humidity control is also essential to create a comfortable work or study environment.
Outdoor air intakes — Incorporating outdoor air into the heating, cooling, and ventilation processes not only provides fresher air, but it also lessens the dependence on the mechanical operation and can substantially lower your energy costs. Some HVAC systems have options for pulling in 100% outside air as the weather allows. In fact, this is a requirement of modular building HVAC systems in many school districts.
Unit size — The size of your HVAC unit will be dependent on the square footage of your building. If you undersize your HVAC unit, it may not keep up with the demands of your space. But if you oversize your HVAC unit, you can create a lot of wasted energy.
Sound — In the past, modular HVAC options were condemned for being noisy and distracting. However, modern systems offer sound reduction systems that cut down on the noise created by vibrations and energy transfer.
Programmable thermostats — Your building’s heating and cooling can be controlled through a basic thermostat. However, upgrading to a programmable thermostat will allow you to conserve energy by changing your HVAC setting based on prime occupancy hours.
Maintenance — Monthly, seasonal, and annual maintenance can prolong the life and efficient operation of your HVAC system. An easy first step is to upgrade to high-efficiency pleated filters. They use an electrostatic charge to grab the smallest particles of debris to keep air quality cleaner and system operations running more smoothly.
Efficiency — Modular HVAC systems are available in both gas and electric operation. Gas HVAC systems are more efficient because they heat faster. Therefore the burners are instantly hot when they come on. This makes gas a better option in colder climates. Gas also tends to be cheaper energy than electric energy.
On the other hand, electric HVAC units are more affordable than gas and they often require less maintenance. Electric HVAC systems are a better choice in warmer climates where they are used less often, requiring less maintenance and maximizing affordability.
In summary, gas HVAC units offer savings from energy costs and efficiency, while electric HVAC units provide savings from a more affordable unit cost and less preventative maintenance requirements.
Life expectancy — Typical life expectancy for an HVAC system is 15 — 20 years, depending on a regular maintenance plan and your geographic location. For example, HVAC systems will have a reduced life expectancy when located in a coastal region, near bodies of saltwater. Additionally, electric systems tend to have a longer life expectancy than gas systems, and they require less maintenance.
Installation Options for Modular Building HVAC Systems
There are two installation options for modular HVAC units: wall-mount and root top. Wall-mount HVAC systems are installed at the modular building factory, while rooftop units are attached by a crane at the final job site. Below we outline the benefits of each installation option.
Wall-mount units are the more traditional installation method, where units are attached to an external wall of the building. Their benefits include:
- Fewer man-hours for installation, already tied into a building’s electrical system and ductwork when delivered to the site, saving construction schedule time and cost
- Designed to withstand the strain of delivery and relocation
- Easy accessibility for maintenance
- Installation consistency because they are installed on an assembly line
- Safer installation, no roof walking is required and units are installed within a controlled environment
- Major cost savings because no crane installation is required
- No additional cost or effort when the building is removed from the site or relocated
- Uncomplicated to replace, although replacement is rarely required
- Affordable unit cost
- Often can be set to condition only occupied rooms, depending on building layout
Roof Top Units (RTUs)
Rooftop units are often used when there is limited space between buildings or for conditioning larger permanent buildings. Their benefits include:
- Take up less space
- Create less noise
- Less grass and debris gets into the system
- More attractive building exterior
- Designed to heat and cool large areas efficiently
- More efficient because system balancing is more accurate. Wall-mount units condition from one side of the building to the other while RTUs condition the spaces centralized below them.
- Less accessibility for vandalism