Siefert Mechanical

Siefert Mechanical Providing both light commercial & residential service in St. Louis!

Specializing in new system installs, System replacement, indoor air quality products such as humidifiers, EAC electronic air cleaners, ductless systems (mini splits) & Wi-fi thermostats.

Happy Fourth of July from Siefert Mechanical 🇺🇸As we celebrate our nation's independence and America's 250th Birthday, w...
07/04/2026

Happy Fourth of July from Siefert Mechanical 🇺🇸

As we celebrate our nation's independence and America's 250th Birthday, we're proud to keep our communities comfortable all summer long ☀️

Have a Happy and Safe Independence Day!!

Give us a shout if you’re in the market for a new HVAC system 314-598-1658. Thank you!
06/17/2026

Give us a shout if you’re in the market for a new HVAC system 314-598-1658. Thank you!

Couple of our latest installations Call for a free quote!!!!
06/13/2026

Couple of our latest installations Call for a free quote!!!!

05/30/2026
This is a 25-year-old Goodman Unit I installed that is still purring like a kitten. I think maybe we put a couple of cap...
03/31/2026

This is a 25-year-old Goodman Unit I installed that is still purring like a kitten. I think maybe we put a couple of capacitors in it in those years that’s it

Another one bites the dust! Call for a free quote 314.598.1658
03/31/2026

Another one bites the dust! Call for a free quote 314.598.1658

Before and after, give us a call for a free quote 314-598-1658 thank you
03/21/2026

Before and after, give us a call for a free quote 314-598-1658 thank you

New AC system call for a free quote 314-598-1658
03/11/2026

New AC system call for a free quote 314-598-1658

Couple of installs we just wrapped up give us a call for a free quote 314-598-1658
02/27/2026

Couple of installs we just wrapped up give us a call for a free quote 314-598-1658

Address

O'Fallon, MO
63366

Opening Hours

Monday 8am - 4:30pm
Tuesday 8am - 4:30pm
Wednesday 8am - 4:30pm
Thursday 8am - 4:30pm
Friday 8am - 4:30pm

Telephone

+13145981658

Website

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