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.

Another one in the books! Call for a free quote 314-598-1658. This is an 18.5. Seer heat pump system. Super efficient
08/11/2026

Another one in the books! Call for a free quote 314-598-1658. This is an 18.5. Seer heat pump system. Super efficient

A little commercial action this afternoon!! nice to switch up a little bit from residential to commercial.
08/04/2026

A little commercial action this afternoon!! nice to switch up a little bit from residential to commercial.

We just wrapped this install up today, give us a call for a free quote 314-598-1658These units are extra popular and onl...
08/04/2026

We just wrapped this install up today, give us a call for a free quote 314-598-1658

These units are extra popular and only going to get more popular! This is an inverted modulating communicating system 18 seer. This customer is already happy happy happy.!!!

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

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

Alerts

Be the first to know and let us send you an email when Siefert Mechanical posts news and promotions. Your email address will not be used for any other purpose, and you can unsubscribe at any time.

Shortcuts

Share