It happens a lot. Maybe you’re moving into a new house in a new neighbourhood. So, you come across a unit on the front lawn that looks like the exterior unit of an HVAC system.
However, it’s significantly different from the outdoor units you’ve seen before. Alternatively, maybe you’ve never used a heat pump before.
So, the big unit on the front lawn catches you by surprise. Is it a heater? Perhaps a new kind of furnace? Or, could it be an air conditioning unit. It’s important to understand the difference lest you make costly mistakes down the line.
There is no functional difference between an air conditioner and a heat pump. Both expel hot air from your home while blowing cool, or conditioning, the air inside
Read on to learn the key features of heat pumps and how to tell whether your house has one. We also answer common questions relating to heat pumps in case you become confused.
How Do I Know If I Have a Heat Pump?
The easiest way to know whether you have a heat pump is to head to your thermostat, turn “Heat” ON, and wait a few minutes to see what happens. If you feel the heat coming from the return vents on the air handler (typically on the wall) with the propane/gas line shut, then you most likely have a heat pump system.
What is a Heat Pump?
Heat pumps are heating systems powered by electricity. A heat pump doesn’t require any other energy source to run because it’s not burning fuel to generate heat.
Instead, it transfers heat from a cooler place to a warmer place using the refrigeration cycle. As such, the heat pump is like an air conditioning unit working in reverse.
Instead of extracting heat from your home and dumping it outside to lower indoor temperatures, a heat pump extracts heat from outdoor air and dumps the heat inside your home to raise indoor temperatures.
How Does a Heat Pump Work?
Heat pumps comprise four main parts, i.e., the outdoor compressor, indoor evaporator, and refrigerant lines connecting the two units. Of course, you can also count the electrical wires connecting the compressor and condenser.
The heating process begins when temperatures drop significantly in your area, typically below 68°F to 72°F, depending on your thermostat setting. As soon as temperatures drop below the setting, your thermostat sends a signal to the heat pump’s control board requesting heat.
Upon receiving the request, the condenser (located outside the house) turns on a fan located within it. This fan is responsible for drawing cold air from the atmosphere into the condenser.
At this point, the freon in the refrigerant lines is extremely cold (low temperature) and at low pressure. The fan is strategically positioned to pass the air entering the unit over the cold refrigerant coils, allowing the refrigerant to absorb most of the heat.
Then it passes through a compressor that raises its temperature (turning it to gas) and pressure and passes it to the indoor air handler.
At the indoor air handler (also known as an evaporator), cold air from the house is passed over the high-temperature, high-pressure gas in the indoor refrigerant coils, facilitating the transfer of heat from the coils to the air.
The warm air is then sent back into your home while the low-temperature, low-pressure refrigerant condenses to liquid and flows to the outdoor condenser.
The liquid refrigerant passes through an expansion valve, which relieves the pressure, thus lowering the temperature. Then the low-temperature, low-pressure refrigerant cycles through the outdoor coils where it absorbs heat and the cycle continue.
If a heat pump is the wrong size, it may not keep you comfortable in your home. Oversized units may create bursts of warm or cold air, tricking thermostats or control systems into shutting off the system before the entire house reaches the desired temperature
Key Features of a Heat Pump
Modern heat pumps are made up of four basic components;
The Condenser
The part of the heat pump that you can see when you’re at the gate is called a condenser. Its sole purpose is to compress the refrigerant from liquid to gas while also raising its temperature. This allows the refrigerant to absorb heat which is then transferred indoors.
Evaporator or Air Handler
The part of the air handler that you can see inside the house, usually on the wall, is the air handler or evaporator. The main purpose of the evaporator is to enable the transfer of heat from warm refrigerant coils to cold air from the house.
Refrigerant Lines
You may or may not see the refrigerant lines. however, all hat pumps have them. So, they may just be sealed away. Sealing also protects them from exposure to direct sunlight.
Anyway, the refrigerant lines are responsible for transferring refrigerant from the outdoor condenser to the indoor air handler and back, repeatedly.
Electrical Lines
Alongside the refrigerant lines are electrical wires that connect the indoor and outdoor units, allowing the two units to communicate through electrical signals.
Of course, the electrical wires also power components of the outdoor compressor, including the fan.
How Do I Know I Have a Heat Pump or Central Air?
Unfortunately, the striking resemblance between heat pumps and air conditioners often causes confusion.
The following are four ways to know you have a heat pump;
1. Turn it On and See Whether it gives off Heat
The easiest way to tell whether you have a heat pump or air conditioner is to turn on the appliance and see what happens. Make sure the appliance’s switch it turned ON and select “HEAT” mode on the unit.
Then wait at least two full minutes and place the back of your hand about a foot from the return vents on the indoor unit. Can you feel the blowing air? More importantly, what’s the temperature of the air?
If the indoor air handler is blowing warm or hot air, you have a heat pump. Otherwise, you’re likely dealing with an air conditioner.
Keep in mind, though, that heat pumps can blow cold air due to refrigerant leaks, a bad reversing valve, or faulty components. So, you may need further tests to prove beyond doubt that you have a heat pump.
2. Check the Thermostat for Emergency Heat
Heat pumps have a special feature known as “emergency heat” which steps in if the unit is damaged or overwhelmed.
The reasoning behind the emergency heat feature is that sometimes it gets extremely cold outside to the extent that heat pumps are unable to pump meaningful heat into the house. The emergency heat setting (such as a gas furnace) is meant to relieve the heat pump in such situations.
There are three relatively simple ways you can check to see if your unit is a heat pump or just an air conditioner. First and foremost, you can check to see if the unit says heat pump anywhere on it. Often units will say somewhere on them if they are a heat pump.
Secondly, AC units don’t have an emergency heat setting because they don’t need one. Therefore, if your indoor unit has an “emergency heat” setting, it’s definitely not an air conditioner.
Fortunately, it’s not difficult to confirm the presence of emergency heat on an appliance. First, check on the thermostat for “EM,” “EMER,” “EM Heat,” or “EMERGENCY” settings.
Alternatively, check the thermostat screen for the same phrases. If the heat pump has emergency heat, you’ll find the evidence in these two locations. But, remember that not all heat pumps have emergency heat.
3. Check the Outdoor Unit’s Label for Further Evidence
The outdoor units of both air conditioning units and heat pumps contain two important labels that can help you determine whether you have a heat pump or air conditioner.
First, locate the manufacturer’s label. It’s typically white and contains many specifications of the appliance, including size, model, and serial number.
If it’s a heat pump, you’ll likely find the terms “Heat Pump” or “HP” on the label. Meanwhile, cooling system labels usually have the terms “AC” or “Air Conditioner.”
If that doesn’t work, check the yellow Energy Guide label. The Energy Guide label is mandatory on all HVAC appliances as per DOE regulations. Although this label rarely contains the words “heat pump” or “air conditioner” or their initials, the energy efficiency data will give you a clue about what you’re dealing with.
Heating systems must have the term “HSPF” on the yellow label. The term refers to a heating appliance’s “heating seasonal performance factor” which gives a heat pump’s overall energy efficiency during a heating season.
If it also has the term SEER (Seasonal Energy Efficiency Ratio), it’s a dual-function heating and cooling system, also known as a split system. However, it’s best to focus on the HSPF rating.
4. Try to Locate the Reversing Valve
You should have found out whether you have a heat pump or air conditioner by now. However, if you’ve been unlucky thus far, the one evidence that will never fail you is the presence of a reversing valve inside the outdoor unit.
The reversing valve is only found in heat pumps. More importantly, it’s present in all heat pumps. Therefore, any appliance without one isn’t a heat pump.
The purpose of the reversing valve is to control the direction of refrigerant flow. It’s a cylindrical metal tube with four valves and a slide inside the tube that moves back and forth when your heat pump changes modes.
Changing modes is important during defrosting when the heat pump functions almost like an air conditioner, drawing heat from your home and sending it to the outside unit to thaw frosted condenser coils.
This is a critical process without which the heat pump cannot work. Of course, the reversing valve also enables the heat pump to switch to air conditioner mode in reversible units. Nevertheless, it must be present in a heat pump.
Advantages of a Heat Pump Over Traditional AC
If you’re shopping for a space cooler, a heat pump may be a wiser buy compared to an out-and-out cooling unit because you can reverse it to heat your home during the cold season.
Meanwhile, a traditional air conditioner only functions as a cooler and become unhelpful during the cold season.
When to Consider a Conventional AC Over a Heat Pump
It makes more sense to opt for a conventional air conditioner over a reversible heat pump if don’t need heating (live in a tropical climate) or don’t need additional heating sources because you already have enough cover.
For instance, it makes little sense to buy a heating system if you already have a sufficient furnace plus electric room heaters for emergencies.
How Do I Know If I Have a Heat Pump or Furnace?
It’s very easy to know that you have a heat pump and not a furnace. All you need to do is check outside the house for an outdoor component of the heating system. If it has an outdoor component, you have a heat pump. Otherwise, you have a furnace.
What’s the Lifespan of a Heat Pump?
The average lifespan of a heat pump is 12.5 years as most units last between ten and fifteen years. However, keep in mind that some heat pumps can last up to three decades with good maintenance. On the same note, you may sometimes need to replace your heat pump after eight years or less.
How Much Does a Heat Pump Cost?
A new heat pump costs $3,875 to $10,000, thus $6,938 on average. However, the actual price of each unit depends on several factors, from size to brand and efficiency rating. Meanwhile, heat pump installation costs range from $68/hour to $150/hour, depending on the heat pump’s brand, your location, and time of the year.
FAQs
How can you Tell Whether you have a Two-Stage Heat Pump?
It’s easy to know whether you have a single-stage or two-stage heat pump. If your heat pump works at the same speed throughout, it’s a single-stage model. However, if it heats less on milder days and more on colder days, it’s a two-stage unit.
Is it Normal for a Heat Pump to have Frost on it?
Yes, it’s completely normal for heat pumps to have frost on them during the cold weather. It happens when the temperature of the air surrounding the outdoor unit drops below the freezing point. Fortunately, all heat pumps have built-in defrosting mechanisms to thaw the unit.
What’s the Difference Between SEER and HSPF on a Heat Pump?
SEER stands for Seasonal Energy Efficiency Rating, which measures the appliance’s cooling efficiency during the summer. Meanwhile, HSPF stands for Heating Seasonal Performance Rating, which measures the appliance’s heating efficiency during the winter. If your appliance has both, it’s a reversible heat pump that doubles as an air conditioner.
Do I Need to Cover my Heat Pump in the Winter?
No, you don’t need to cover your heat pump during the winter. if you’re worried about the snow and frosting, the appliance’s built-in defrosting cycle will take care of that. If the frosting persists, the defrost mechanism is overwhelmed or may have failed. However, a quick diagnosis by an HVAC professional will set things right.
Summary
It’s not too uncommon for users to confuse air conditioners for heat pumps and vice versa. Similarly, it’s possible to wonder whether your home heating solution is a heat pump or a furnace. Now you know how to know that you have a heat pump.