AUX heat can cost about 2 to 5 times as much as running your heat pump. If there's a wire in the W1 connector, make sure it says AUX heat. **Note that if your Emergency Heat light is on but your thermostat is NOT set to Emergency Heat, this is an indicator there’s a problem with your heat pump and you should call for advice and service.**. At this point, refrigerant gets so cold outside that compressing it becomes nearly impossible, and thus it can’t absorb what little heat is left. All these are great questions! Virtually all heat pump stats, no matter the age, have both an Emergency switch and an automatic Aux mode (although with older stats, the control logic that activates Aux may be poorly implemented). Types of AUX heat (and why it matters) Heat pumps have 2 forms of AUX heat: Electric resistance (default) Gas furnace; The electric resistance option is like the electric coils you see inside your toaster. Continuing to run a heater in these conditions could do tremendous damage to it, so you need to shut it off. Auxiliary heating turns on automatically to help heat your home more quickly if the temperature drops suddenly. Generally, the NTE will use the heat pump if it needs to heat three degrees or less and auxiliary heating if it needs to heat up four or more degrees. It does not support virtually any other kind of heat pump, such as a 1-stage heat pump with separate 2-stage furnace heating (dual fuel) or a 2-stage heat pump with/without AUX heat. heat except when really needed" intelligent algorithm. So on this blog, the experts at Parks Heating & Cooling take a look at both of them and explain the important differences between the two. What is it? Please call to get service when this happens. When you have temperatures that cold, even the slightest amounts of water vapor in the air can condense and freeze, resulting in frost on your outdoor coil that can result in your entire heater freezing over. Emergency Heat is when you use your supplemental heat (2nd stage) by itself, without the use of your heat pump (1st stage heat). Exactly as the name implies, in emergency situations only. Auxiliary heat is the electric heat strip in your air handler that is supplemental heat. The unit outside your home is a heat pump and the unit inside the home is the auxiliary heating system. Sign Up for Our Brand-New Parks Newsletter. Therefore, a heating system stuck in AUX heat will run up an energy bill. Electric heat strip - This electric heat strip is auxiliary heating (or “aux heat” as it shows up on your thermostat). They will work in tandem when the temperatures drop to those cold numbers. AUX heat turns on to keep you warm. The diagram on Nest indicates that W1 and W2 are Aux heat, and OB is "heat pump". Heat pumps need a supplemental heating source. Emergency heating needs to be turned on manually under Settings > Equipment and that will always use your Emergency/Auxiliary heating instead of your heat … Air-source heat pumps work on a novel principle: instead of directly producing the heat that you need to keep warm through the winter, the heat pump will find heat energy in the outside air and bring it into your home, using refrigerant as the medium of heat exchange.. Knowing the difference between your heat pump’s auxiliary heat and emergency heat will help address the question from above. And in that case, you should also call a professional for help.. Aux heat still doesn't start until the difference between set temp and current temp is 4 degrees. Because consumers have many more auxiliary heat options to work with for augmenting heat pumps, this allows them to experience a winter or two in a milder climate zone without the feature before committing to the extra investment, whichever one it may be. Moving heat- In heat mode, your heat pump is like an air conditioner working in reverse to pull heat from the outside to inside your home (the opposite of how it works in cooling mode). So when should you use your Emergency Heat? HEAT" or "EMERGENCY HEAT" instead of "HEATING" (as appropriate) when it is using the electric heating coils. What Is the Difference Between Auxiliary Heat & Emergency Heat. We are always here to help as much as we can! Only run your system in this mode when you truly need it to avoid damaging your central system. Heat pump systems have two units - one outside the home and one inside the home. When turned on, your compressor and heat pump shut off entirely and your radiation heat strips in your system turn on. However, at temperatures in the 20s and 30s or below, your heat pump may not be able to produce heat at all because there simply won’t be enough in the ambient air to extract. How to minimize the use of auxiliary heat with a heat-pump on your ecobee thermostat Question: We have a heat pump and recently installed an ecobee thermostat. This indicates that Nest is using its "avoid aux. Both “auxiliary” and “emergency” heat have to do with the operation of these electrical strips. Generally at temperatures below 40 degrees, your system needs to run defrost cycles every few hours to operate. You can choose how much expensive AUX heat your system will use when your heat is running. Auxiliary heat uses electric resistance heating, which is much less efficient than your heat pump. EM heat is an option on your thermostat that you can manually turn on to activate backup heating. For example, if your house is not warm and it’s because something has happened to your outdoor unit, then it’s time to turn Emergency Heat on and call for service. Emergency heat should only be used on very cold days when the heat pump is unable to keep the house warm. The Emergency Heat Switch on a Heat Pump confuses a lot of people. Most of the time, you won’t even notice the switch has happened unless you look at your thermostat and see that the “AUX” light is turned on. *The Nest Thermostat E supports a single stage heat pump with/without AUX heat and a single stage heat pump with separate single stage furnace heating (dual fuel). If you have a heat pump, it is best to increase your heat setting by only two degrees at a time to prevent your auxiliary heat from operating. Emergency Heat is when you use your “second-stage” (supplemental heat)  by itself without using your “first stage” (heat pump). **Note that if your Emergency Heat light is on but your thermostat is NOT set to Emergency Heat, this is an indicator there’s a problem with your heat pump and you should call for advice and service. After making these settings, the Nest "home screen" (showing the current temperature and whether it's heating" will show "AUX. Note: In some cases, your heat pump’s AUX heat could be a gas furnace, but since Phoenix typically has mild winters, some AZ homeowners will have electric resistance as their AUX heat. Important Notes on Nest Thermostats. Yes, as ridiculous as it may sound, your heater can literally freeze, usually at temperatures of around 40 degrees Fahrenheit or below. It has run almost continually the last few nights when the … Different systems and thermostats have different ways of determining when the second-stage heat comes on to assist the heat pump, but it is always done automatically. Supplemental heating sources are known as “second-stage” or “back-up” heating. The Emergency Heat setting locks out the heat pump and forces the auxiliary heat source (in Minneapolis homes, it’s most likely a gas furnace) to provide 100% of the home’s heating. The thermostat will sense this and turn on electric heat strips automatically turning on the “AUX” heat light. It’s used when there’s something wrong with your “first stage” heat. Heat vs Emergency Heat. Both of these wires are needed for Emergency Heat. This is when the outside is around 35-40 degrees and the indoor temperature is around three degrees cooler than the thermostat setting. And that’s not necessarily a good thing. I'm getting an E33 error, and Nest thermostat is telling me that I can only have one auxiliary heat wire. In order to further understand what these modes do, it’s important to know how a central heater works. However, bear in mind that you will be using a considerable amount of extra energy in doing so, thus the name “emergency” being attached to it. Both of these heat modes are designed to work in extremely cold temperatures, and choosing the wrong one could have potentially bad consequences for your heater and for your home in general. I assume that the heat pump's "emergency heat" (or maybe "auxiliary heat"?) So while the heat does turn on at a 2 degree difference, it will blow cool air from that point until the 4 degree swing is met. We’re available 24/7/365! If you’ve taken even a slightly longer glance at your thermostat, you may have noticed it has a couple of extra heat settings: one called “auxiliary heat” and one called “emergency heat.” While most people know these two settings exist, few people actually know the difference between them. Both systems are actually controlled by the device’s thermostat. I have a Lennox heat pump with electric emergency/aux heat, I also have a humidifier. But what happens when you still need heat? In this video we go over the heat pump balance feature in the programming of the NEST thermostat. Once the ice on the heat pump has mostly melted, the heat pump goes back to normal and AUX heat turns off. If you look at the backside of Nest Thermostat, you can see labels (O/B , AUX/E) – which means this thermostat is compatible with heat pumps (O/B) and also compatible for heat pumps with aux/emergency heating (AUX/E). But the house just doesn't warm up until it gets above freezing, indicating that the emergency heat is never coming on. I have a 20 year old Carrier 3 ton split unit. When the temperature inside your home drops about two or three degrees below the temperature the thermostat is set to, auxiliary heating kicks on to help warm your home more quickly. ** Auxiliary Heat. That means it has to reverse the flow of refrigerant again in order to allow the hot fluid to flow through your coil and melt off any condensed or frozen snow or ice. Do I turn it on when it’s really cold? EM heat is NOT the same thing as AUX heat: AUX heat signifies that your heat pump has automatically switched over to backup heating because temperatures are too low. No-frills heat pump systems without the auxiliary heat capability sometimes make that feature an add-later option. Here's the long and short of it. AUX heat can also start if the pump can’t handle the outside heat on cold winter nights. Thus,when your heater has been on for a few hours, your system will have to defrost itself in order to continue functioning. Auxiliary heat/ Emergency heat helps the heat pump keep up when cold outside or the temperature differential on the thermostat is large. Your auxiliary heat supplements your heat pump’s heat––it doesn’t replace it. and (2) When the thermostat is set to Emergency Heat only (brown wire on E). AUX/AUX1 and AUX2. Especially when the weather is below 40 degrees. Auixiliary Heat will turn on automatically when heat can no longer efficiently transfer heat from the outside air to heat pump. During freezing weather, the outdoor heat pump will be too cold to quickly heat your home, which is when the auxiliary heating system would kick on. Emergency Heat Hello, It's going to be really cold here in Alabama the next few nights and I'm trying to decide what is the best approach to handle the cold nights. The outlet temperature with and without Aux heat depends on outdoor temp, wattage of electric heat strips and CFM setting. So the signal will either come from the White Wite on W2 or the brown wire on E to turn on the heat strips. When you turn on Emergency heat, this will only turn on the indoor unit and back-up heat. When turned on, the heat pump shuts off entirely, allowing you to receive heat without damaging your outdoor heat pump system. First “Auxiliary Heat”, “Strip Heat”, “Emergency Heat”, “ Radiant Heat ” are all used to reference the same heating mechanism; your electric heat strips that come with a heat pump. The emergency heat setting has to be manually switched on and should only be used in temperatures below 30 degrees. The important thing to remember is that “AUX” heat is fast and dependable but it’s also more expensive than heat … heat pump balance doesn't seem to do anything other than raise the outside temp level that the aux heat is able to kick in. Otherwise, just keep your thermostat set on “heat.” There is no temperature to switch it over to emergency heat, even if your heat pump is running constantly due to cold weather. Simple: during this period, your system turns on a series of electrical radiant heat strips that can still provide you with heat, but while consuming more energy. Having Emergency Heat on can and will be more expensive to run. If the walls of your home are too cold and your heat pump is not powerful enough, AUX heat may be needed in order to make up the degrees. You’d only use this setting when the heat pump malfunctions or is damaged and fails to provide heat . This happens sometimes when it’s colder than average and on the verge of extreme temperature drop like Nashville experienced this last spring. The emergency heat setting has to be manually switched on and should only be used in temperatures below 30 degrees. Now I keep on getting alerts that the Aux heat is running. Auixiliary Heat will turn on automatically when heat can no longer efficiently transfer heat from the outside air to heat pump. The E wire normally connects to the ecobee’s W1 terminal. This will provide additional heat as needed. The Auxiliary heat gets automatically turned on by your HVAC system to supplement the heat pump output when your system can’t keep up. Your heat pump only is the “first stage” heating. This is known as running on “auxiliary heat.” Generally, this can’t be controlled manually, but is instead switched over to automatically when your system either senses that it has been running for too long, or too much ice has built up on the outdoor coil and it needs to begin a defrost cycle. However, during cold weather this cycle can actually build frost on your outdoor coil. Call Parks Heating & Cooling today at (704) 313-1443 or contact us online to schedule a heating service with our team. 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