Wouldn’t it be nice to be able to use one unit to provide both your cooling needs and heating needs? In a sense, you’d be able to pay for the price of just one system but get the benefits of two systems! Well, this is what heat pumps provide. But, there is a catch. Heat pumps are effective in outdoor temperatures that are above freezing (32 degrees F). Once the temperature drops below freezing, heat pumps begin to lose their effectiveness and their ability to provide heat.
But why? That’s what we’re going to explain. We will also provide some solutions to improve the heat pump’s effectiveness in colder temperatures.
First off, What is a Heat Pump Exactly?
A heat pump is an air conditioner that can also provide heat all within the same unit. Pretty awesome, right? A heat pump as an air conditioner takes in warm air from the inside environment (home, business etc.) and then disperses that warm air outside. It then disperses the remaining cool air into your home or business.
Related: Heat Pump vs Air Conditioner – What’s the Difference?
As a heater, the heat pump pulls in air from the outside environment and extracts warmth from that air before dispersing it throughout your home or business. It’s like the best of both worlds!
But then, why doesn’t everyone have a heat pump? Great question!
Heat Pump Limitations
While the theory and design of heat pumps are great, there are some drawbacks. The main limitation of heat pumps is their effective temperature range. For producing heat, heat pumps are only effective at temperatures that are above freezing. But, why is this?
Heat pumps are limited because of how they produce heat. Rather than creating their own heat, like a furnace does, heat pumps pull in warm air to use from the outside air. Remember, an air conditioner doesn’t produce cool air. It simply removes the warmth from the air and then disperses the left over cool air back into the inside environment. A heat pump works the same way, just in reverse.
So, the colder it is outside, the less warm air there is for the heat pump to use.
As a heat pump loses its effectiveness to deliver heat, it also begins to drop in its efficiency. This means that the heat pump is working hard trying to produce heat, but it can’t due to the lack of warmth in the outside air.
The Most Effective Temperature Range
As we’ve already discussed, below freezing is definitely not an effective temperature range for a heat pump. But what is?
Well, since we know how heat pumps operate when producing heat, we can conclude that the warmer it is outside, the more effective the heat pump will be. But, noone is going to be running their heat pump for heating purposes in 70 – 80 degree weather. At least I hope not!
So, for cooler temperatures, I’d say around 50 – 65 degrees F is what I would call the sweet spot for a heat pump. In this range heat pumps are very efficient and effective. They are still effective in the 40’s and even down into the 30’s. But, as I stated earlier, once the temperature outside drops below 32 degrees F, you will probably notice a significant drop in the heating ability of a heat pump.
Because of the ineffectiveness of heat pumps under certain circumstances, they are recommended for southern and coastal states. They can be used in our area of Jackson TN, but there might be days when it’s just not enough (wait for the next section on solutions). Instead, think of states like Florida, California, and other southern climates that aren’t regularly below freezing in the Winter months.
But, wait. There’s more! There are options that allow you to have a heat pump in colder climates and for it to actually be effective!
Solutions!
The best option for colder climates is to have a furnace for your heating source. Furnaces don’t have any limitations when it comes to delivering heat. It’s their main function and what they were created for. Remember, they create heat rather than simply passing on heat from the outside air. But, let’s get back to our focus here which is heat pumps. Let’s get into solutions for sufficient heat if you have a heat pump or are wanting one and are located in a colder climate. I’ve listed them from the least expensive to the most expensive.
Related: Heat Pump vs Furnace – Which is Better?
1) The first solution is something known as electric heat strips, or auxiliary heat. When a heat pump is struggling to produce heat, installed electric heat strips can be activated and will begin to add another source of heat to your heating system. These nice additions are sufficient enough to meet your heating needs in most climates.
2) The second solution is a newer product known as dual fuel heat pumps. These heat pumps operate just like the standard heat pumps that we’ve described here, but they have a little secret. When the outside temperature drops to a certain level, let’s say 32 degrees F, the supplemental furnace takes over. So, you have the convenience and efficiency of a heat pump during its optimal temperature range and the heating power of a furnace whenever it is needed. The only requirement is that you will need some sort of gas as your fuel source, not just electricity.
3) Lastly, and the most expensive upfront, is the geothermal heat pump. A geothermal heat pump extracts heat from the ground instead of the air. Because the temperature of the ground is much warmer and consistent, this equates to more consistent heat to the heat pump despite colder outdoor temperatures. These types of heat pumps don’t need a back-up heat course such as heat strips or a furnace.
Thanks for Stopping By!
I hope this has given you some clarity on heat pumps and their effectiveness in certain temperatures. Hopefully this information will aid you in the future when it comes to deciding on a heat source for your home or business!
We are a heating and air company located in Jackson TN. If you live in Jackson TN or in the surrounding areas, feel free to give us a call at (731) 300-1030 if you are interested in a heat pump or want more information. We provide professional installation services, offer great rates on new heat pumps, and provide free estimates!
Do you have any experience with heat pumps in your life? What has been your experience? Do you have anything to add to what we’ve shared?
Feel free to comment below. We’d love to hear from you!
I live in north central Illinois. I just bought a heat pump along with a new, 96% efficient, gas, forced air furnace. What temperature do you think is the “break even” point where it is no longer worth using the heat pump? Is running the heat pump while adding heat from gas worth the energy the pump will use?
Hi Denniy! As the blog post mentions above, a heat pump’s sweet spot for providing efficient heat is typically found when the temperature outside is in the 50’s and low 60’s. Heat pumps are usually still pretty effective when the temps hit the 40’s as well, but when the temperature outside starts to get near freezing and below, heat pumps can start to drop in efficiency. So, it’s really up to you. You have information to go on to make your decision. Kicking on the furnace when the temps outside get around freezing is a good place to start I would say.
Some advocates recommend using heat pumps even in Alaska. And in all temperatures . Nonsense.
Set yr emergency or secondary heat to swap over at below 40F. But it should not be cycling btw primary and secondary so if your local temperature is often 40F then adjust to avoid that.
And contrast yr electric and gas bill. Oh these fun eco times.
I would have thought that by now there would be enough heat pump/gas installations in my area that someone would know, at what temperature, does the cost of gas vs. electric cost less to heat with? At what temperature, does the electricity to operate the heat pump exceed the cost of just using natural gas? Natural gas is measured in “therms” instead of B.T.U.’s to further complicate the matter. How many kWh = 1 therm? Doesn’t anyone know the answer to this question?
Hi Dennis. It depends, as you mentioned, where you are located, the cost of natural gas in that area vs the cost of electricity. Therefore the temperature will vary from one location to the next.
1Kwh is 0.034129563407041 Therm
https://www.convertunits.com/from/kWh/to/therm+%5BU.S.%5D
1 therm = 100,000 Btu
1 kWh = 3,412 Btu
The reason natural gas fired heaters are used in many homes is because natural gas is relatively inexpensive, about $2.5 per million BTUs wholesale compared to power. Your Utility probably charge around $1 therm. In most state a kWh of electricity approximately $0.20. It takes about 29 kWh to equal 1 therm.
So heating your house with one therm of gas costs $1 versus $6 for electricity. On a cold winter day the average house might use 20 therms so your heating cost could be $20 per day for gas or $120 for power to heat your home with electricity.
WHAT IS THE COST, PLUS INSTALATION OF GEOTHERMAL HEATING , SAY FOR A 1300 SQ FT HOME WITH A BASEMENT
Hey Cecil! Thanks for your comment. It’s difficult to give an accurate estimate for a geothermal system without an in-person visit due to the many factors involved. It can also vary by location as well. I would recommend having a reputable HVAC company in your local area come out to give you an estimate. Most of them can provide you one for free.
What is a rough % cost for a geothermal well (assuming various well driller prices based on supply and demand and possible pre-existing hand dug well) as it fits into the complete geothermal heating/cooling system’s cost?
Hey James. Thanks for your comment. I would recommend getting a free estimate from a local HVAC company in order to get an accurate % and number. There should be local HVAC companies in your area that will give you a free estimate and you will then have accurate numbers for your area. Hope this helps!