HVAC Repair in Arnold, MO
Homes here need heat from October through April and cooling from May through September. If your system quits, tell us what it's doing and a licensed contractor who covers Jefferson County will get in touch.
Tell us about the job
It takes about a minute.
Arnold runs its system almost year round
Heat runs October through April here. Cooling picks up right after and holds through September. That leaves your furnace and your air conditioner only a few weeks a year when neither one has to work.
Winter nights average 25°F, cold enough that the burner cycles on and off many times a night to hold the house steady. Each start puts wear on the igniter. Summer afternoons average 87°F, and the compressor runs long stretches to keep up, which is hard on the capacitor and the contactor. A lot of homes here heat with electricity, so when a storm cuts power, the furnace stops with it. The area has seen 11 winter storms and 53 damaging wind events over the past ten years, and in 2024 close to one in five Missouri households went at least a full day without power.
- 7 months
- October through April, your system heats
- 5 months
- May through September, it cools
- 25°F
- the average winter night it heats against
- 87°F
- the average summer afternoon it cools against
NOAA nClimDiv, 1991–2020 normals
- Why is my heat not working?
- Start with the thermostat. Make sure it's set to heat and the temperature is set higher than the room. If that's fine, check the breaker for the furnace and, if it's a gas furnace, check that the switch on the unit and the gas valve are both on. A furnace that won't light at all often has a bad igniter or flame sensor, and that's a job for a contractor. With winter nights here averaging 25°F, don't wait on a furnace that isn't heating at all.
- Why is my system running but not cooling the house?
- Check the air filter first. A clogged filter chokes off airflow across the coil and the house won't cool even though the system runs. Next check that the outdoor unit isn't blocked by leaves, grass clippings, or anything sitting against it, since it needs open air to release heat. If the filter is clean and the outdoor unit is clear, the system may be low on refrigerant or have a failing part, and that needs a contractor's diagnosis.
- What can I check before calling for HVAC repair?
- Check the thermostat settings, the batteries in it if it uses any, and the breaker for the system. Check the air filter and replace it if it's dirty, since a clogged filter causes both heating and cooling problems. Look at the outdoor unit and clear away anything blocking it. If the system still isn't working after that, a contractor will need to look at it, and with 53 damaging wind events recorded here over the past ten years, it's worth checking the outdoor unit for storm damage too.