For Private High School, Simple HVAC is Better

St. John’s Lutheran Church in Mattoon, Illinois – a long standing private religious school serving students from preschool to 8^th grade – is stepping up to meet persistent demand for private schooling in a community that houses corporate offices for businesses like First Mid Bank & Trust and Rural King, as well as factories for Bimbo Bakeries, Mars Inc., and Justrite.

The church commissioned local builder Drake Homes to build the new school, breaking ground in March to open up to students in August. The lightning pace at which the trades came together to build the 36,700-square-foot building can be attributed to the planning of Drake Homes to get the roofs over a complete wing so that the mechanical contractors could start on that wing and, as a team play, move the project along more efficiently.

“I’ve got a lot of metal ducting that has to be hung for the DOAS units, which runs down the length of every hallway and is ducted to each classroom. So long as it was under roof, whether it rained or whatever, our team could make it work,” said Mitch Rawlings, of Varner and Rawlings Heating and Air, noting they were also able to stay out of the way from other tradespeople with the early access.

With the help of Gunn and Pagelow and Capitol Group, the team at Varner and Rawlings was able to install everything in a timely manner.

Rawlings and his team designed and installed the HVAC system, including three Dedicated Outdoor Air System (DOAS) systems, 13 Gree mini-splits (ductless variable speed and variable volume heat pumps) with 42 indoor heads and automated programing to help cut back on operating costs.

Operation of this complete system goes as follows:

• Two of the DOAS units are 100% outside air, supplying conditioned air around 70 degrees to all the classrooms and hallways during occupied hours. They completely shut down during unoccupied hours, saving energy.
• The third DOAS unit is dedicated to the gym. It also brings in outside air but has an energy recovery ventilator, or ERV, wheel included in it for operation during occupied hours. During unoccupied hours, the unit sets back and closes the outside air damper. These units also have controls that will allow 3-hour occupied settings for sporting events and ceremonies.
• The mini-split systems are controlled by a master controller that has set up and set back times and temperatures for 38 indoor heads. There are individual thermostats in each room that can be adjusted within the boundaries set by the principal. This system is also capable of turning selected rooms or areas to occupied settings when there are events after setback hours.

“If you look at it, it’s actually a pretty simple system. Nothing too complicated about it, and it works. That’s the best part,” Rawlings said.

For Rawlings, it’s personal. He has family going to this school. If it was not for his company, Drake Homes, and several others committing financial support to make this school a reality, then his granddaughter would have to attend public schools where there could be bullying, shootings, and other unsatisfactory conditions – a rising concern for the community.

“I see religion and respect for one another being taught here as well,” he noted.

Rawlings said providing clean air and properly exhausting stale air and CO2 by bringing in plenty of filtered and conditioned outside air is a priority. Every filter is easily assessable for maintenance to stay on top of air quality.

Proper air exhaust is another important task.

“I go into a lot of places such as churches, retail businesses, and restaurants that have no outside air coming in. This creates an unhealthy environment in these locations,” Rawlings said, noting this spreads germs, sickness, and results in high CO2 levels. “I have a granddaughter going to school here so clean air is very important to me.”

Band rooms, science rooms, restrooms, offices, storage rooms, common areas, and locker rooms all have exhaust. To save on energy, most have time clocks on them to shut down after unoccupied hours while the locker rooms stay on 24/7.

“This system has redundancies so that if one day a mini-split system goes down, it would only cause up to five rooms to have issues. You still have your DOAS system supplying 70-degree air to that space,” Rawlings said, noting he also installed electric back up wall heaters at the main entrance, side entrance, and incoming water main area as an added precaution.

Rawlings said he was pleased with the quick turnaround on the project, as his granddaughter has already started classes.

“I think this project went pretty smooth with Drake Homes being the builder and them also coordinating with all the trades to make things go as smoothly and as efficiently as possible,” Rawlings concluded.