Furnace Repair in Florissant, MO
Furnaces here run from October through April. If yours quits, tell us what it's doing and a licensed contractor who covers St. Louis County will get in touch.
Tell us about the job
It takes about a minute.
Seven months of work, twenty-six degree nights
Your furnace runs from October through April here, seven months of the year. On nights that average 26°F, it cycles on and off many times to hold the house steady, and every cycle puts wear on the igniter and the parts that start the burner. Most homes in the area heat with gas, so when the igniter or the flame sensor gives out, the burner won't light and the house goes cold.
St. Louis County sees its share of winter storms and high wind, and Missouri households lost power often enough in 2024 that furnaces went down with them. A furnace that will not restart after an outage usually just needs its power resupplied or its switch reset, but if it stays off, that is worth a call.
- 7 months
- October through April, your furnace is on duty
- 26°F
- the average winter night it heats against
- 75%
- of homes here heat with gas, so most furnaces here burn gas
- 9 winter storms
- in ten years, the nights a failure hurts most
NOAA nClimDiv, 1991–2020 normals
A new furnace would cut about $180 a year off heating for a typical St. Louis County home.
Estimates for a typical St. Louis County home, compared with an older unit built to the previous federal minimum, from EIA household energy data, Missouri fuel prices and NOAA climate normals. Your home will differ.
Repair makes sense when one part has failed and the heat exchanger is sound.
Replacement makes sense when the heat exchanger is cracked or the furnace keeps needing parts.
- Why won't my furnace turn on?
- The most common reason is the thermostat, the power supply, or the gas supply to the unit. Check that the thermostat is set to heat and the temperature is above room temperature, and check the breaker for the furnace. If those are fine, the igniter or the flame sensor may have failed, and a contractor will need to test them to know for sure.
- Why is my furnace blowing cold air?
- Furnaces blow cold air for a few seconds when they first start, while the burners light and the heat exchanger warms up. If cold air keeps coming, the igniter may have failed, the gas valve may not be opening, or the thermostat fan setting may be set to "on" instead of "auto", which pushes air through even when the burners are off. A contractor can check which of these is happening in your furnace.
- Why won't my furnace pilot light stay lit?
- A pilot light that won't stay lit usually means the thermocouple has worn out. The thermocouple sits in the pilot flame and tells the gas valve it is safe to keep the gas flowing. When it fails, the valve shuts the gas off as a safety measure, even though the pilot was burning fine a moment before. It can also mean a draft is blowing the flame out or the pilot orifice is dirty, so a contractor will need to look at it to know which one it is.