Short answer: No. Switching your thermostat to emergency heat or “em heat” just because it's cold outside will just raise your energy bills like crazy. Don't use emergency heat mode unless your heat pump stops
There's no specific timeframe for using the emergency heat setting. If you need it for a few hours, the system should be fine. Or, keep it on until the unit thaws out or is fixed.
It does not damage your unit to run it. What emergency heat is, is heat strips like are in a portable space heater. They are really inefficient at heating, they draw a lot of electricity. But they create heat and work in emergencies. Should you use it?
This can cause concern, as auxiliary heat typically is not supposed to run all the time. While it's normal for auxiliary heat to kick in during exceedingly cold temperatures, running it too long may indicate an issue with the heat pump.
Using EMERGENCY HEAT or AUX mode can significantly increase your electric bill compared to regular HEAT mode. Only use these settings in true emergencies when you need immediate warmth.
This heating method works incredibly efficiently until the outdoor temperature reaches about 35 degrees. At this point, the heat pump has difficulty extracting enough heat from outside to keep up with the thermostat setting. This is when many people assume it's time for switching their heat pump to emergency heat.
High energy bills
The cost of running your home on Emergency Heat would be astronomical. Turning to this setting switches the source of your heat from the heat pump to the electric heat strip, which is significantly less efficient and more costly.
Auxiliary Heat – This is the secondary heat source that turns on automatically. Emergency Heat – This is when you turn on the secondary heat source.
So how fast should a furnace heat a house? On average, once you turn on your furnace, it should take about an hour to increase indoor temperature by 1 degree. Afterwards, it's 45 minutes per degree.
Cost of Energy Bills in AUX Heat Mode
Because your heat pump and backup heat source work together, AUX mode consumes more energy. This leads to increased energy bills — your costs may be up to 50% higher when the device is using AUX heat.
Most standard heat pumps will function at 100% efficiency until the outside temperature reaches about 40° F. However, when the temperature dips below this, most heat pumps are not able to maintain efficiency. They become much less effective at temperatures between 20° F to 30° F.
When the outdoor temps are between 35 and 40 degrees or colder, the heat pump may struggle to pull enough warmth from the air outside. This is where the heat pump auxiliary heat system comes in. The auxiliary system often uses electricity as its main source of power, but auxiliary systems can also use gas or oil.
Short answer: No. Switching your thermostat to emergency heat or “em heat” just because it's cold outside will just raise your energy bills like crazy.
Yes – sleeping with your heat pump on at night means you can keep your room temperature the same while the temperature drops outside.
When the nights begin to get cold, turning on your home's furnace and keeping it running throughout the day and night is expected and fully safe to do. However, many people use other types of heating systems in their homes, including space heaters and electric heaters, which can pose a fire risk in some situations.
In general, 80 degrees is too hot for a house if people are inside. However, if people aren't home during the day or for vacation during the summer, an indoor temperature of 80 degrees can save energy until you return and lower the temperature.
A furnace that's running non-stop is not necessarily bad. During the coldest days in winter, it is normal for a furnace to run almost constantly to keep the home warm. As long as the furnace is running efficiently and not making strange noises, the constant operation is likely nothing to worry about.
Cooling a house from 90 degrees to 72 degrees typically takes about 2 to 4 hours, depending on various factors.
Don't: turn on emergency heat just because it's cold.
While it is true that the emergency heat setting will kick on when it drops to near or below freezing temperatures, as mentioned earlier, it is important to remember to turn your thermostat back to the regular heat setting when this occurs.
Auxiliary heat will come on and off as needed, emergency heat will remain on until you deactivate the setting.
Your auxiliary heat, or secondary heat source, should come on when your heat pump is struggling to heat your home effectively. The thermostat will trigger auxiliary heat when: The outside temperature is below 40 degrees or a set aux heat trigger temperature. The heat pump is in defrost mode.
Switching your system over to the emergency heat or auxiliary setting means your furnace has already been working as hard as it can, lowering its eficiency. Switching it over to emergency heat is always more expensive, so you will likely see an additional spike in your utility bill during that time period.
If someone is at home in the daytime, 72° F (22° C) is a good start, but aim for 68° F (20° C). If everyone is away from home in the daytime or you're asleep at night, we feel 66° F (19° C) to 62° F (17° C) is best.
There are a few possible reasons your heat pump might be blowing cold air: Your heat pump is in defrost mode. There's an issue with your heat pump. It's below freezing, and you need a backup heat source.