These frequently asked questions are essential for homeowners to ask themselves when maintaining their indoor air quality.
If you have questions about your air conditioner or need professional service, working with a trusted local HVAC company makes a difference.
Thomas Hoffmann Air Conditioning & Heating LLC provides reliable AC repair, maintenance, and installation services for homeowners throughout the St. Louis metro area.

Most homeowners should replace their air filter every 1 to 3 months. However, the exact timing depends on several factors:
- Number of people in the home
- Pets in the household
- Indoor air quality
- Type of filter used
A dirty air filter can cause:
- Reduced airflow
- Higher energy bills
- Frozen AC coils
- Increased system wear
Changing the filter regularly is one of the simplest and most important AC maintenance tasks homeowners can perform.
The ideal thermostat setting varies by personal comfort, but many experts recommend: Around 78°F while you’re home. This temperature helps balance comfort and energy efficiency. You may want to set the thermostat slightly higher when you’re away to save energy. Using a programmable or smart thermostat makes this process easier and more efficient.
If your air conditioner is running but not cooling your home, several issues may be responsible. Common causes include:
- Dirty air filter
- Low refrigerant
- Frozen evaporator coil
- Thermostat problems
- Dirty condenser coils
If changing the air filter doesn’t solve the problem, professional AC repair may be necessary.
Most central air conditioning systems last between 12 and 15 years. However, lifespan depends on:
- Maintenance history
- Installation quality
- Climate conditions
- Usage levels
Regular AC maintenance can help extend the life of your system and reduce the likelihood of unexpected breakdowns.
Air conditioners are sized based on cooling capacity measured in tons or BTUs. Choosing the right size system requires evaluating factors such as:
- Home square footage
- Insulation levels
- Window placement
- Ceiling height
- Local climate
There are several ways homeowners can reduce cooling costs. Helpful tips include:
- Changing air filters regularly
- Sealing air leaks around doors and windows
- Using ceiling fans
- Scheduling annual AC maintenance
- Installing a programmable thermostat
Energy-efficient upgrades may also help reduce monthly utility bills.
Deciding whether to repair or replace your air conditioner depends on several factors. These include:
- Age of the system
- Cost of repairs
- Overall system condition
- Long-term energy efficiency
A professional HVAC technician can help evaluate your system and recommend the most practical solution.
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At Thomas Hoffmann Air Conditioning & Heating, we pride ourselves on being a locally owned and operated HVAC company. With more than 30 years of experience and a master technician and mechanical engineer as our owner, we can replace, repair, and maintain your business or home’s HVAC system.