When the outside temperature plummets, homeowners rely on their heat pump systems to keep their homes warm and comfortable. Heat pumps are great at extracting heat from the outdoor air and pumping it indoors. However, the temperature outside is unbearable during extreme cold snaps, or your heat pump fails.
You may need to turn on your thermostat’s emergency or auxiliary heat setting. You can use the emergency heat to help provide backup heat, yet it comes at a cost.
Emergency heat is a backup form of electric resistance heating element, similar to space heaters. It is much less efficient and uses more expensive electricity than the primary heat pump. That’s why emergency heat should only be used in an emergency, as it can lead to a significantly higher energy bill.
Emergency heat mode is designed for emergency situations only when your heat pump can’t maintain your desired indoor temperature. In our guide, you can learn why to use emergency heat while you wait for your heat pump to be repaired or the cold snap is over. By the end, you’ll better understand how emergency heat works and what using an emergency heat setting means to heat your home. (Read What Size Duct Do I Need For A 12×12 Room)
What is Emergency Heat?
To understand the higher cost of emergency heat, it helps first to understand what emergency heat is and how it works compared to your normal heat pump system.
Heat Pump Systems
Heat pumps work well as very efficient heating and cooling systems that move heat rather than generate it directly.
During the winter, the outdoor unit extracts heat from the outside air and pumps it indoors to the indoor unit to warm your home to the desired temperature. The initial investment in a heat pump system may be higher than natural gas or oil, but they pay for themselves over time with lower energy bills.
Backup Heating System
While very efficient, heat pumps have limitations. At freezing outdoor temperatures, typically below 30°F, they can struggle to extract enough heat from the outdoor air. That’s where the emergency or auxiliary heat system comes in and powers a heat strip to produce warmth.
Emergency heat is a supplemental heating system setting on your HVAC system. This uses electrical resistance heating when the primary heat source can’t keep up, or you have a problem with your heat pump. It ensures your home can stay warm even in frigid winter conditions.
When to Use Emergency Heat
You switch to emergency heat on your heat pump thermostat to offer a backup heat source. It is expensive to run and should only be used in emergency situations:
Heat Pump Failure
Emergency heat can keep your home warm if your outdoor heat pump unit stops working because of a mechanical failure or power outage. Switch the thermostat to emergency heat and call an HVAC technician if your heat pump may require repair. Using emergency heat for a short time can be less expensive than allowing your home’s temperature to drop dramatically.
Emergency heat is electric and doesn’t use other components. So, your compressor and heat pump shut down entirely; thus, you can produce heat without damaging your outdoor heat pump system.
Extremely Cold Temperatures
When temperatures plummet below where your heat pump stops working efficiently, you may need a boost from the emergency heat until your heat pump can be fixed. Check the outdoor temperature displayed on your thermostat. If it’s below about 25°F, you can turn on the emergency heat to supplement your heat pump to combat cold in your home. (Learn How Fast Does Spray Paint Dry)
Why Emergency Heat Costs More?
Emergency heat is essentially a secondary heat source to supplement the heat from your HVAC. Now you know when the temperature drops. You can see why running an electric heat pump on emergency heat rather than regular heat setting has higher costs when you turn on emergency heat:
Less Efficient System
Heat pumps move existing heat rather than produce heat directly, like furnaces. This makes them 300-400% more efficient than when you use the emergency heat on your thermostat. Emergency heat systems rely on electric resistance coils or electric heat strip – the least efficient type of electric heating.
More Expensive Energy Source
Emergency heating type of heating uses electricity as the energy source. Electricity costs 3-4 times more per BTU of heat than natural gas or heating oil. And electricity is usually the most expensive fuel to begin with. Together, this leads to high bills when you use the emergency heat setting.
Estimating the Cost of Emergency Heat
It’s hard to pinpoint precisely how much a standard heat pump running emergency heat will increase your bill. Here are some factors contributing to the cost:
Higher Electric Bills
You can expect your electric bill to be about 3-5 times higher when relying on emergency electric heat than your heat pump. The increase depends on your electricity rate and how often you run the emergency heat.
Compare to Regular Heat
Homes heated with natural gas or heating oil will see an even more dramatic cost jump by switching to electric emergency heat from a gas furnace or oil boiler. You may spend 6-10 times more compared to regular use.
Note: Varying costs of emergency heat include the size of your home, the number of doors and windows, etc. (Read Ductwork For Wood Stove)
Saving on Emergency Heat Costs
Since emergency heat comes with high costs, here are some tips to minimize costs when you need to use your emergency heating system:
Only use emergency heat when necessary, when your heat pump needs to be fixed, or when temperatures are well below freezing. And don’t overheat your home – keep the temperature set on the thermostat at a moderate 68°F when you use this setting.
Upgrade HVAC Unit
If emergency heat to keep warm is used frequently, consider upgrading to a more powerful and efficient heat pump system to increase the amount of heat in your home. A dual-fuel system with gas or propane backup may also save on costs.
Conclusion: Maintain Heat Pump & Limit Emergency Heat Use
Prevention is the best medicine regarding when emergency heat is used and to keep costs down.
Keep your outdoor heat pump unit well-maintained and inspected yearly to reduce failures requiring auxiliary heating.
A modern, ENERGY STAR-rated heat pump uses less power and is the most advanced and reliable on the market. Investing in upgrades to an aging or underpowered heat pump system can pay dividends through lower emergency heating costs.
With some vigilance and preventative care, you can keep your reliance on emergency heat to a minimum, and you have confidence in your heat pump’s performance.
FAQs: How Much To Run Emergency Heat Setting?
How much does it cost to run emergency heat per hour?
On average, emergency electric heat can cost $3-$5 per hour to run, compared to $1-$1.50 per hour for a heat pump system. This can add up quickly over a full day or week of use.
Is it cheaper to use space heaters or emergency heat?
Space heaters are more expensive to operate per unit of heat provided. But they allow you to heat a smaller area vs. the whole home. Used wisely, they may cost less than full emergency heat.
Should I turn down the heat at night if on emergency heat?
You can save by lowering the temperature at night and when away from home. Aim for a minimum of 60°F to prevent pipes from freezing. (Read Convert Home To Propane)
What temperature is too cold for a heat pump to work?
Most heat pumps have difficulty extracting enough heat below about 25°F-30°F. Check your owner’s manual for the recommended temperature to switch on emergency heat.
How much higher are my bills if I use emergency heat all winter?
Suppose you relied solely on electric emergency heat all winter instead of the heat pump. Emergency heat may cause your bills to be 200-300% higher from higher rates and constant operation.