How to put a modern A/C unit in oldest unrestored church in the country

Mission Concepcion in need of new unit

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SAN ANTONIO – Mission Concepcion, the oldest unrestored stone church in the country at 303 years old, needs a new air-conditioning unit. But there’s a problem: If you put a modern A/C unit in the church, it could potentially damage the historical site.

Melissa and Enrique Mejia have been parishioners at the Mission Concepcion for four years.

Enrique Mejia received all his sacraments at the church. The couple was married there, and they also had their 7-month-old daughter, Emery, recently baptized at the church. 

Melissa Mejia said that to have so many special moments in the designated World Heritage site holds a special meaning to the couple.

“It's a beautiful thing,” Melissa Mejia said. “I don't think words can really describe it unless you actually go through it.”

The Mejias hope those moments can be preserved. And preservation is the goal behind a recent University of Texas at San Antonio study of the church.

The church's A/C unit is 30 years old and badly needs to be updated. The hold up: The church wasn’t built to have an A/C unit.

Mission Concepcion isn’t like a modern building, which usually has insulation.

“(The church is) not well-designed for this kind of environment,” said Tony Martinez-Molina, assistant professor of architecture at UTSA, who is leading the study. “This kind of temperature difference we have, probably 30-, even some days, 40-degree difference between the inside and outside, that creates huge stress on the walls.”

One of the areas of the church that has gone through some of the most damage is a room off to the side it, where one of the original frescoes is severely fading. Researchers believe the damage may be caused by a high level of moisture in the room.

“We installed, for example, these data loggers that record the temperature and humidity that record every 15 minutes,” Martinez-Molina said.

He said he hopes by the end of the yearlong study, they can figure out what's creating the deterioration, figure out a design for a new A/C unit and also come up with a solution for all the water gathering outside the building.

Enrique Mejia said he hopes the building can be preserved.

“Making sure we can do what we can to preserve it so that other future generations can also experience it, to have those same kind of moments that we share here,” he said.

The study started in June. UTSA hopes to have all the data collected by the end of the summer.

Researchers hope to have a solution designed by June 2020.

The study is being funded by the Archdiocese of San Antonio.

About the Authors:

Sarah Acosta is a weekend Good Morning San Antonio anchor and a general assignments reporter at KSAT12. She joined the news team in April 2018 as a morning reporter for GMSA and is a native South Texan.