If your house feels uncomfortably warm during summer—even with the air conditioning running—you’re not the only one struggling. Many homeowners deal with overheating indoors, often due to hidden HVAC or insulation issues. We spoke with certified HVAC professionals who shared five simple, fast-working solutions to keep your home cooler when the temperatures rise.

1. Your AC Unit Might Be the Wrong Size

An air conditioner that’s too small for your home’s square footage may never cool your space effectively. If your system runs non-stop but fails to hit the desired temperature, it might be undersized.

“Older homes often have outdated or incorrectly sized HVAC systems, especially if they were installed without energy efficiency in mind,” says Phil Oliver, owner of Air Treatment Heating and Cooling.

The fix: Consider upgrading to an AC unit that’s appropriately sized for your home. A licensed HVAC technician can calculate the correct tonnage for maximum cooling efficiency.

2. Poor Insulation and Air Leaks Let Cool Air Escape

Insufficient insulation or poorly sealed air gaps allow heat to creep in and cool air to leak out, which forces your system to work overtime. This issue is especially common in attics, around windows and doors, and in older duct systems.

“Leaks can cause 20–30% of conditioned air to be lost before it reaches the living area,” Oliver explains.

The fix: Schedule a professional inspection to improve insulation, seal leaks, and address inefficient ductwork.

Explore more solutions at Energy Star, which offers homeowner guidance on sealing and insulating homes.

3. Dirty Filters and Condenser Coils Reduce Efficiency

Clogged air filters and dirty condenser coils are common reasons for poor HVAC performance. These block airflow and prevent your AC from releasing heat properly.

“I’ve seen outdoor AC units so clogged with dirt and debris, they couldn’t breathe,” Oliver adds.

The fix: Replace air filters every 1–3 months and gently clean your outdoor unit with a hose to improve airflow.

4. Leaky or Imbalanced Ductwork

Faulty ductwork may not distribute cool air evenly across your home. This often results in hot spots, especially on upper floors or in remote corners.

“Uneven airflow can be caused by duct leaks or blocked vents,” says Randy Fuller, owner of Fuller HVAC.

The fix: Get your duct system inspected and balanced by an HVAC professional. Make sure vents aren’t blocked by furniture or closed in rarely used rooms.

5. Outdated Windows Let the Heat In

Older windows can significantly impact your indoor temperature, particularly if they face direct sunlight. Without energy-efficient glass, your cooling efforts might go to waste.

“To manage indoor heat better, install energy-efficient windows or use reflective blinds,” advises Elizabeth Shavers, general manager at Oncourse Home Solutions.

The fix: If replacing windows isn’t in the budget, invest in blackout curtains or solar shades to reduce heat gain.