The Differences Between Heat Pumps and Air Conditioners
When your heating and/or cooling system starts to malfunction, getting the unit fixed quickly can be the difference between comfort and misery. You can probably guess that the metal box outside is responsible, but is it an air conditioning unit or do you need heat pump repair? It may seem like an obvious answer; an air conditioning unit cools, and a heat pump pumps heat. Or does it? While the names may make the function sound straightforward, they are actually misleading, and share more similarities than it sounds at first glance.
What is an Air Conditioner?
An air conditioner is a unit that cools down an area. They are able to lower the temperature of the room by several degrees depending on their power, and are a boon in hotter climates or regions.
How do air conditioners work?
It seems simple; an air conditioner blows cool air into a room and reduces the overall temperature. But this is actually incorrect. Have you ever noticed that home air conditioners have vents on the outside that blow out hot air for some reason? This hot air might appear to be a byproduct because of how hard the unit has to work, but it’s actually the goal of the a/c unit. Because heat travels one way–from an area of higher heat to one of lower heat–the air conditioner doesn’t blow cold air into the room, but pulls the hot air from the inside and blows it out.
There are several different ways the air conditioner can achieve this, depending on the specific cooling method. A swamp cooler or evaporative cooler uses the unique properties of water and cools the air of the room by the evaporation of water. Other units function similar to a refrigerator, using chemicals called refrigerants that evaporate into gas and condense back into liquid over and over again, using the heat pulled into the unit to cause this phase change and absorbing the unwanted heat in the process.
What can go wrong?
Since each part of the air conditioner is essential for it to function properly, if one of the pieces malfunctions, it could cause the air conditioner to be less efficient or stop working entirely. A hole in your refrigeration system can cause the chemical to leak out, and if the leak is big enough, the air conditioner won’t work. This can also potentially cause health problems, as the chemicals can evaporate into the air and then be breathed in by people in the room.
Another common issue is a lack of air flow. Have you noticed that sometimes, even on very hot days, that the outside of an air conditioning unit can freeze over? This can happen even in temperatures of 100 degrees or more. One major reason this happens is because there isn’t enough air circulating through the unit. Air conditioners have an air filter that can get clogged by air contaminants, dirt and more. If enough of these contaminants get stuck to the filter, it can block the air from entering and circulating, and if the unit is at high power, then cold air on the inside can become trapped and freeze the coils. This can cause them to stop working or stop the fan from rotating, meaning that even though the air conditioning unit is cooled extremely well, your room won’t be.
What is a heat pump?
As the name suggests, a heat pump works by pumping heat. But the name is also deceiving, as a heat pump does more than simply heat up your house–it can cool it down as well.
How do heat pumps work?
Heat pumps take heat energy from a source and move it to another area. Like air conditioners, heat pumps have similar parts including fans and refrigerant chemicals. A reversible heat pump is in essence both a heater and an air conditioner; it can heat or cool your room depending on your needs. The same principles apply to both devices: the refrigerant changes states and absorbs heat, but releases it in a different area depending on user input. Usually, all this involves is a simple flip of a switch to change whether the heat is transferred from inside a room and taken out (cooling) or taken from outside and brought in (heating).
What are some common issues?
Since heat pumps normally operate during both summer and winter times, they share some common problems with air conditioning units but have unique issues that can occur in winter too. A little bit of ice dusting the surface of a heat pump during winter is normal, and many units come with a built-in defroster to combat freezing. However, the coils can still freeze up and cause the unit to malfunction. Since these units are generally outside, in winter, other, seemingly unrelated problems such as a leaky gutter can drip too much water onto the unit and cause it to freeze.
A problem related specifically to reversible heat pumps is failure to switch modes. This can cause the uncomfortable mistake of increasing the heat in summer or cooling in winter. First, make sure you switched the mode! If it’s in the right mode but still doing the opposite, the unit may be dirty. If not, then it may be a bigger problem such as a refrigerant leak or the compressor not working.
How can I tell if I have a heat pump or A/C unit?
The easiest way is to see if the label on the compressor says that the unit is a heat pump. If there isn’t a label or it’s not obvious from the label, check for a reversing valve, a small tube with four copper pipes connected to it. You can also check your thermostat and see if it has a setting for emergency heat. Emergency heat is a setting to still get heat into your home if your heat pump isn’t working properly, but requires significantly more energy. Getting it fixed right away will save money in the long run, often in a matter of months. Because these and other complicated problems can come up with these advanced units, if a simple DIY repair like cleaning the air filter doesn’t solve the problem, always make sure to call a professional, reliable heat pump repair company to make sure the job’s done right.