Learning Center
Learn, compare, and decide with confidence
Honest, plain-English HVAC answers for O'Fallon homeowners, organized the way you actually shop: understand how systems work, compare your options, then take the next step.
Learn · how systems work
Understand the equipment in your home
Plain-English explainers for the systems Swiss Air sells and services, written for humid summers, cold snaps, and real St. Louis-area homes.
How central air conditioning works The cooling loop, humidity, and when to repair or replace. Interactive diagram
How furnaces / gas heating works Combustion heat, AFUE, and Missouri cold snaps. Interactive diagram
How heat pumps work One all-electric system for heating and cooling. Interactive diagram
How ductless mini-splits work Zoned comfort without ductwork. Interactive diagram
How indoor air quality systems work Filtration, purification, and humidity control. Interactive diagram
How tank water heaters work Storage heat, recovery, and the tankless path. Interactive diagram
How smart thermostats work Sensors, schedules, and compatibility. Interactive diagram
How dual-fuel systems work Heat pump + furnace hybrid for St. Louis winters. Interactive diagram
Browse all guides & articles
Compare · weigh your options
Make a confident, informed choice
Repair or replace your system? An honest framework, plus a free second opinion. Heat pump vs. furnace in Missouri Efficiency, cost, and climate fit compared. Dual-fuel vs. heat-pump-only Cold-snap strategy for St. Louis winters. Central AC vs. ductless Whole-home ducts vs. zoned mini-splits. Single-stage vs. two-stage vs. variable-speed Comfort tiers and furnace AFUE context. Tank vs. tankless water heater Upfront cost, hot-water capacity, and lifespan. Should I…? Honest decision guides Verdict-first frameworks, repair or replace, heat pump fit, zoning, and more. How much does a new system cost? Installed ballpark ranges, with furnace, AC, water-heater, and mini-split guides. Rebates & financing Verified Ameren Missouri & Spire rebates + low monthly payments. Build & price a comfort system Transparent low-to-high pricing, instantly.
Learn · homeowner Q&A
Troubleshooting, lifespan & permits
How long does a furnace last in Missouri? Lifespan, warning signs, and when to plan a replacement. Why isn't my AC cooling the house? Common causes, from airflow to refrigerant, and quick checks. Why AI doesn't know how to price equipment Bad vs. good prompts, then get a Free Second Opinion. HVAC permits & code What O'Fallon and St. Charles County homeowners should know. Home safety, season by season CO safety, freeze protection, humidity control, and storm-season surge defense. Seasonal HVAC maintenance checklist Season-by-season homeowner tasks, check items off as you go. Homebuyer HVAC inspection checklist What to check before closing, the things a general inspection skips.
Glossary · HVAC terms defined
Speak HVAC like a pro
- SEER2
- The current U.S. seasonal cooling-efficiency rating for air conditioners and heat pumps. A higher SEER2 means lower cooling energy use.
- AFUE
- Annual Fuel Utilization Efficiency, a furnace's heating efficiency as a percentage. 95% AFUE means 95% of the fuel becomes heat.
- HSPF2
- The seasonal heating-efficiency rating for heat pumps. Higher HSPF2 means more efficient heating.
- Heat pump
- An all-electric system that moves heat to both heat and cool a home, replacing a separate AC and furnace.
- Tonnage
- An AC or heat pump's cooling capacity. One ton equals 12,000 BTU per hour.
- BTU
- British Thermal Unit, a standard measure of heating or cooling energy.
- MERV
- Minimum Efficiency Reporting Value, an air-filter rating. Higher MERV captures smaller particles.
- R-454B (A2L)
- A newer low-global-warming refrigerant phasing in to replace R-410A under the 2025 federal transition.
- Manual J
- The industry load-calculation method used to correctly size equipment for your specific home.
- Variable-speed
- Compressor or blower technology that adjusts output for more even temperatures and higher efficiency.
Permits & Code
Do I need a permit for that?
What O'Fallon and St. Charles County homeowners should know about HVAC permits and inspections and how Swiss Air Heating & Cooling handles the paperwork for you.