What Temperature Is A Heat Pump Not Effective?

Heat pumps can be a great option for those that want a more environmentally friendly heating source. There are many conditions in which a heat pump will not only be ineffective but will stop working altogether. How low of a temperature is too low for heat pumps?

Although heat pumps are a great heating source, they are not as effective in low temperatures. Heat pumps start to lose their ability to heat a home efficiently when the temperature hits 40 degrees. When the temperature falls to below 30 degrees, heat pumps will lose 100% of their efficiency.

Some regions may need a backup system, while a heat pump would be a waste of money in other areas.

There are many ways to get the most out of your heat pump. Read on to not only find out how your heat pump works but how to keep it working as the temperature starts to drop.

What Is A Heat Pump?

A heat pump is a heating and cooling system that is hooked up outside of your house. Much like an air conditioning unit, some have their heat pump installed next to their house.

It is a fairly simple concept to heat homes, but they are not for every geographic location. There are a few different types of heat pumps, but the most common are:

  • Air sourced
    • These heat pumps will work by moving air between the air in your home and the outdoor air
    • These are by far the most popular
  • Ground source
    • These heat pumps work by moving the air in your home and the air under the ground
    • These are a little more expensive

Your heat pump will have a coil that works as a condenser when trying to cool the air and an evaporator when trying to warm the air.

There will also be a unit inside of your home (much like a window air conditioning unit, but it is attached to a wall) it will have a fan to help blow the air into your home. 

How Do Heat Pumps Work?

To better understand why your pump may not be effective in different temperatures, it’s good to know how exactly heat pumps work. This will help you to know when it is not working to its peak performance.

Heated air is sucked in from outside then flows through the refrigeration coolant, which is then compressed.

When the coolant is compressed, it raises the temperature much higher. Then the air is pumped into your home, warming it. This is the reason why the outside temperature greatly affects how your heat pump will work.

If you still are not sure how heat pumps work, Lennox has a very informative video describing it, and it gives you a nice visual.

Heat Pumps In Temperatures Below 40-Degrees

When the outside temperature reaches 40 degrees, the efficiency will greatly decrease.

The way the unit simply uses outdoor air and warms it a little means if the temperature is too low, it won’t be able to warm your house as easily. 

While it can, and will, blow out air that is warmer than the outside air. It probably won’t make a noticeable difference in your home.

For example, if its 40 degrees out and it can only get your home to 60, that’s still very chilly for most people

Heat Pumps In Temperatures Below 30 Degrees 

When you try and run your heat pump during freezing weather, you will be left with a cold house. Heat pumps may be efficient but cannot handle freezing weather because they are not a heater. 

They only rely on the warmth of the outside air. If there is no heat to pull in and warm, it will only be blowing in cool air. Unless you have a backup heating system, a stand-alone heat pump will waste money in cold climate areas.

The heat pump will still try to run but will use far more power than before, adding to your electric bill and pushing the unit to its limit while still blowing in cool air.

What To Do When The Temperature Drops

It is advised not to turn your machine off when the temperature drops; instead only turn it off when it starts to no longer pump any warm air. If it is blowing cold air, turn it off.

To help your heat pump to operate at its peak during cooler climates, you should:

  • Make sure the outdoor unit to the heat pump is clear of debris for the best airflow. If air can’t flow through easily, the heat pump can’t work properly.
  • Make sure nothing is falling off your roof onto your heat pump, such as water, rain, or leaves.
  • Check the air filter to see if it needs to be replaced

If everything looks good and your heat pump is still not blowing warm air, and the temperatures are around 40 degrees, you may need to call to have your unit checked out.

Heat Pumps Controlling Humidity

Heat pumps can reduce your home’s humidity level when it’s cooling your home and increase humidity when heating your home, which helps create a comfortable home.

If your heat pump is not controlling the humidity level as it should, there are a few things you can do:

  • Check that your coil is clean, free of dust, debris, and frost
  • When it is blowing cool air in warmer months, you may need to raise the fan speed. The quicker the air can pass through, the less likely it is to build up moisture
  • Add an additional dehumidifier in your home. This is not ideal for everyone.
    • There are full home dehumidifiers, but there are also smaller ones to help control the humidity level a little more. The latter is less expensive.

Do High Humidity Levels Outside Effect Heat Pumps?

Higher humidity levels during the winter can absolutely create issues for your heat pump and your nice warm home.

Higher humidity means more moisture passing through the unit. When the air is cold and wet, it makes it harder for your heat pump to heat the air.

It will cool the air even more as it passed through the coils in the heat pump.

As the moisture builds up inside of the heat pump, frost could potentially build up on the coils, which could block airflow, make your heat pump blow cold air, and potentially damage your heat pump.

Some heat pumps will have defrosters that you can hit a button on a remote to the heat pump to trigger the defroster to start working.

More expensive heat pumps have a sensor that will automatically start defrosting any built-up frost. 

Where Heat Pumps Are Most Effective

It is easy to see that heat pumps are far more effective in areas that don’t reach close to, or below, freezing during the coldest winter months.

If your area does not have warmer winters, it will probably not be worth getting a heat pump.

If you live in areas known for decently warmer winters in the 50s–60s, even at night/at the lowest, a heat pump will be the perfect addition to your home.

Are Heat Pumps Expensive – Initial Cost & Upkeep

Heat pumps are one of the most efficient means on the market to heat and cool a home. In the right regions, it can and will work for you all year long. Potentially cutting out the cost of buying:

  • Electric heaters
  • Gas & electric furnaces
  • Oil, gas, or kerosene for heating your home which adds up to hundreds every winter if not more
  • Outdoor AC units
  • Window AC units

Not to mention lowering the risk of fires caused by common fire starters such as tipped over heaters, which are easily tipped over, and the gas, kerosene, and oil-fueled ones are an even bigger risk and put off harmful pollutions into the air.

Heat pumps can cost anywhere from $3,000 to $10,000 for the unit and having it installed. The price depends on many factors:

  • Size of your home. The bigger your home, the larger the heat pump unit you will need
  • Number of stories. If the indoor units need places on the 2nd/3rd levels of your home, it will cost more in material and labor.
  • Type of heat pump
  • How much ductwork. You may need to have ductwork replaced or added to your home
  • The area where you live. Some regions cost more due to supply and demand
  • The brand that you buy. There are brands for every price range.

That may seem like a hefty price, but when you take into consideration that they can save you an average of 40% on your energy bill, it may well be worth it.

Source: Modernize – Heating & Air

Heat Pumps Losing Efficiency 

Heat pumps are a very efficient way to heat your home. No, they are not for every home. If you live in colder climate areas, have freezing winters, or even winters that dip below 40 degrees often, a heat pump is not ideal for you. 

If you live in a region that has warm winters, a heat pump will help reduce your electric bill by almost half. The cost may be a big chunk of money upfront, but the benefits outweigh the one-time big price.