Cooling vs refrigeration

Cooling and refrigeration get used as though they were interchangeable. They are not, and the distinction is not pedantry — it explains why some appliances make a room colder, some make it warmer, and some make you feel cooler while doing neither.

Refrigeration is a specific process. A refrigerant is compressed until it is hot, run through a coil where it sheds that heat, allowed to expand until it is cold, and run through a second coil where it absorbs heat. Repeat. That is the vapor-compression cycle, and it is the same in every machine that uses it.

Cooling is just the result of something getting colder, by whatever route. Refrigeration is one route. Evaporation is another. Shading, night ventilation and thermal mass are others still, and none of them involve a compressor.

The critical thing the cycle does not do is destroy heat. Heat is conserved. Every refrigeration machine is a heat pump in the literal sense: it picks heat up in one place and puts it down in another, and it adds its own electrical consumption to the pile on the way.

Read the fridge row again. A refrigerator has both coils inside your house: the cold one inside the cabinet, the hot one on the back or underneath. It moves heat from the food into the kitchen, and adds its own electricity consumption on top.

A fridge is therefore, unambiguously, a net heater of your home. So is a freezer. So is anything that makes ice indoors, which is why freezing water to put in front of a fan heats the house more than the ice cools it.

1. A portable air conditioner is a compromised design for a structural reason. Its hot side is a hose rather than a wall, and on a single-hose unit the condenser air comes from the room itself. The hot side is not fully outside, which is the entire problem — single hose against dual.
2. A heat pump is not a different machine from an air conditioner. It is an air conditioner with a reversing valve. That is the whole of the difference, and it is why one box can do both seasons — heat pump against air conditioner.
3. A dehumidifier is not a broken air conditioner. Both coils indoors is the design intent. In a cool damp basement it is exactly right and an air conditioner is exactly wrong — the basement case.

A resistance heater turns one unit of electricity into one unit of heat. Its coefficient of performance is exactly 1, and no manufacturer can improve it, because it is bounded by conservation of energy.

A refrigeration machine is not making heat, it is moving it, so it is not bounded the same way. The certified mini-split field has a median COP of 2.00 at 5°F and a maximum of 3.28 — two to three units of heat delivered per unit of electricity consumed, in genuinely cold weather.

That is the single most useful consequence of understanding the distinction. Heating by moving heat rather than making it is two to three times cheaper, and it is the reason heat pumps exist at all — when that pays for an installer.

One irritating consequence of the same cycle appearing in different product categories: each category has its own rating scale, and they are not interchangeable.

• CEER — room air conditioners. Certified units span 12.0 to 17.6.
• EER2 and SEER2 — mini-splits. EER2 is the full-load figure and the only one comparable to CEER; SEER2 is a seasonal average and is much higher.
• IEF, in liters per kWh — dehumidifiers. A completely different unit, because the useful output is water rather than temperature.
• CFM per watt — fans. Airflow per unit of power, measuring something that is not refrigeration at all.

Comparing across those scales produces nonsense. The most common version is quoting a mini-split’s SEER2 against a window unit’s CEER, which overstates the gap by a factor of ten — how to read them without being misled.