So, what is your question?

If i only increase airflow why does my system perform better? i have same compressor condenser and evap coil.

I would surmise that replacing the blower fan has resulted in higher air flow and that before the replacement the air flow was too low.

"my ac has always struggled and basically ran 24/7"

"If i only increase airflow why does my system perform better?"

Answer from Copilot Ai:

If the blower in a split‑system air conditioner runs too slowly, the entire refrigeration cycle is pushed outside its design envelope. The immediate effect is insufficient airflow across the evaporator coil, and from there a cascade of predictable failures follows.

Core takeaway

A too‑slow blower causes the evaporator coil to get too cold, leading to icing, poor cooling, high humidity, longer runtimes, and potential compressor damage.

What actually happens inside the system

1. Evaporator coil temperature drops → frost and ice formation

Low airflow means the coil cannot shed heat fast enough. Air lingers on the coil surface, refrigerant absorbs less heat, and coil temperature falls below 32°F.

• Ice begins at the distributor or lower rows
• Frost expands and chokes airflow further
• Eventually the system enters a runaway freeze‑up condition

2. Humidity removal increases briefly, then collapses

Initially, slow airflow increases latent removal because the coil is colder. But once the coil starts icing, moisture can no longer reach the coil surface.

• Indoor humidity rises
• Supply air becomes cold but clammy

3. Temperature distribution becomes uneven

With reduced CFM, conditioned air cannot travel through the duct system at proper velocity.

• Rooms far from the air handler get little airflow
• Hot/cold spots appear

4. Compressor runs with abnormal suction pressure

Low airflow → low evaporator pressure → high compression ratio. This increases:

• Compressor amp draw
• Discharge temperature
• Long‑term wear

5. System may short‑cycle on safety limits

If airflow is too low, the coil can freeze or the heat exchanger (in heat mode) can overheat. Either condition triggers limit switches that shut the system down prematurely.

Why manufacturers specify minimum airflow

Residential systems are designed around roughly 350–450 CFM per ton. Below that range, the coil simply cannot operate in a stable thermodynamic state.

Summary

A slow blower in a split system AC is not a minor comfort issue — it destabilizes the refrigeration cycle. The consequences include coil icing, humidity problems, uneven cooling, higher energy use, and potential compressor damage.

When you replace the motor did you you clean the squirrel cage blower? That may of done it.

Yes i cleaned fan fins. they were ok to start with. so, what fan speed should i have for heating season? less then hi? its a multi level house with poor airflow thru different floors.

Since you have to ask, I'm inclined to say leave it like it is and see how it does heating. The only problems that arise from fan speed heating is too low can cause echanger to overheat and shorten it's life or too high making rooms feel drafty. We know fan speed isn't too low so it's just a matter of seeing how room feels. There's ways of getting multiple speeds from the old furnace but if it's not broke, don't fix it until it's broke.

Good question, and the short answer is that heating fan speed is not simply a case of faster is better.

I run Ocala Pro AC Repair here in Ocala, FL — we see this a lot in Florida heat.

In cooling, the extra airflow you noticed probably helped because a weak blower can starve the evaporator coil, leave rooms uneven and make the system run almost constantly. Heating is different. If airflow is too high, the air can feel cool and draughty even though the furnace is working, and the system can struggle to feel comfortable. If airflow is too low, the heat exchanger can overheat, the furnace can trip its high-limit safety control, and repeated overheating can shorten its life.

What you can safely check yourself is fairly limited, and that is by design. Start with the furnace manual or the rating plate for the recommended temperature rise, and keep a clean filter and open supply and return vents, because a blocked filter changes airflow more than many people expect. When heating is running, note whether the air feels reasonably warm, whether the furnace runs steadily or shuts off and restarts quickly, and whether you smell overheating or hear unusual strain. Do not keep swapping motor speed taps by trial and error, especially with the power on.

If the furnace trips off, blows cold air, cycles rapidly, or you are unsure which lead is meant for heating, call a professional to set the speed and check temperature rise, safety controls and the motor match. Getting that one setting right protects both comfort and the furnace.

I would lean the same way as leaving it where it is for now and seeing how heating goes. Heating and cooling do not always want the same airflow, so a speed that helped in summer can feel drafty in winter if it moves air too fast past the heat exchanger. Before changing any wiring, I would note which speed you are on now, keep the filter clean, and pay attention to whether rooms warm evenly, whether the furnace cycles normally, and whether supply air feels comfortably warm rather than cool. If it heats evenly and cycles normally, that is useful information. If it short-cycles, blows cool air, or leaves rooms uneven, that is the point to stop and have it checked rather than trying another speed by trial and error.

When seeking a solution,I wonder if homeowners want to hear long naritives sprikled with hypotheticals or short,to the point answers.