Before assuming a higher energy bill is just “the way things are now,” it’s worth checking whether your HVAC system is quietly working harder than it should. Here are the most common causes we find.
1. A dirty or clogged air filter
The single most common — and easiest to fix — cause of reduced efficiency. A clogged filter forces your system to work harder to move the same amount of air.
2. Leaky or poorly sealed ductwork
Ducts running through unconditioned spaces like attics or crawl spaces can lose a significant portion of heated or cooled air before it ever reaches your rooms.
3. An aging system nearing the end of its life
Efficiency naturally declines as components wear, even with good maintenance — this is one reason older systems cost more to run than their rated efficiency suggests.
4. Incorrect thermostat settings or an old, inaccurate thermostat
A programmable or smart thermostat set correctly for your schedule can meaningfully reduce runtime without sacrificing comfort.
5. Refrigerant issues in your AC
Low refrigerant (usually from a slow leak) makes an air conditioner run longer to reach the same temperature — increasing both wear and energy use.
6. Poor insulation working against your HVAC system
Even a perfectly efficient system fights an uphill battle in a poorly insulated home — this is worth addressing alongside, not instead of, HVAC maintenance.
7. Skipped maintenance
Dirty coils, worn components, and unnoticed small issues all compound over time into a system that costs more to run than it should.
A maintenance visit can usually identify which of these is driving your bill up — often for less than the cost difference shows up on a single month’s statement.