What is a heat pump and what are its benefits?
Let’s talk heat pumps.
They are common enough to be recognized and talked about, even in Central Ohio, where they are not as prolific as they are in warmer climates.
Heat pumps sit outside of your home, and can be the workhorse of your HVAC system, since it both heats and cools. That means it can run for most of the year.
But it can also work in conjunction with your furnace, which sits nice and cozy indoors. And it can have different stages of use, which can save you money.
Consider this article Heat Pump 101. I’ll cover the basics of the appliance in order to give you a better understanding of it.
We’ll cover the heat pump’s heating/cooling cycle so that you can be better informed when you choose HVAC partners.
- What does a heat pump do in the winter?
- What does a heat pump do in the summer?
- What are the various types of heat pumps?
- How are heat pumps’ efficiency rated?
- Heat pumps paired with a furnace: which does the most work?
- Can I manually switch between my heat pump and furnace for heat?
- Can I use my furnace as the primary heat source and let the heat pump stay idle?
- If propane gets expensive, can I use the heat pump for my primary source of heat?
- What if you have solar panels?
- Why might I have to replace my heat pump along with my furnace?
- Why are heat pumps relatively rare in Columbus?
- Why are heat pumps so popular in warmer climates?
- Why do heat pumps not last as long as other HVAC equipment?
- What is the Cost of a Heat Pump Replacement?
By the end of this article, you will better understand how heat pumps work.
You will also learn the different types of heat pumps available, and the benefits and drawbacks are for each of them.
In the summer, your heat pump is an AC
That’s all it is: an air conditioner with a reversing valve that automatically switches the unit from producing heat to producing cold.
During the summer, a heat pump squeezes the heat out of the outside air and transfers it to the inside of your home.
If you’re looking at a heat pump, it can look exactly like a simple AC. Without knowing the model or seeing the inner workings, there’s often no way to tell the difference between the two.
In the winter, your heat pump is a furnace
In the winter months, the unit’s reversing valve switches, which means the heat pump squeezes the heat out of the outside air and transfers it to the inside of your home.
If it’s an all-electric HVAC system, the heat pump’s warmth can be complemented by heat strips inside the furnace. Heat strips are wire elements in your air handler that are heated by electricity, which in turn heat the air that flows over them. Heat strips are similar to the inner workings of a toaster. They are pieces of conducting metal that get very hot.
The heat is pushed throughout the ductwork by an air handler or a furnace’s blower, and cool air is sucked into the air handler through return ducts to be warmed.
What are the various types of heat pumps?
Entry-level air heat pumps are typically single-stage. This means that they’re either running at 100% capacity or they’re off. While single-stage systems can reliably cool your home, they may struggle with multi-story or large homes. Single-stage air conditioners are going to be the cheapest to purchase and have installed. The good news: A one-stage AC can cool your home adequately, provided it’s sized properly and installed correctly.
Two-stage heat pumps can run at 100%, or at its second stage, which is generally around 70% of capacity. This allows the heat pump to not work at full blast all of the time, saving wear and tear, and ultimately, energy.
Two-stage air conditioners are going to provide more efficiency compared to a single-stage air conditioner.
A variable-speed air conditioner can have up to 700 distinct compressor settings that correspond to varying levels of airflow. Variable-speed air conditioners are going to run the most efficiently, and will generally be the quietest as well, since they’re often operating as low as 40% of their maximum power capacity. You’re also going to save the most on energy costs, and have the greatest degree of control over the temperature in your home. The primary downside is the initial cost. The systems don’t come cheap, even if they largely make up that cost in the long run.
How are heat pumps’ efficiency rated?
Since heat pumps provide both cooling and heating, manufacturers use two different ratings to score heat pump efficiency:
- Seasonal Energy Efficiency Ratio (SEER)
- Heating Seasonal Performance Factor (HSPF)
The higher the SEER rating, the more efficient the system is. The XR20 has a rating of 20 SEER, which means that it can get to zero degrees outside and that sucker will still be working at some capacity.
Heat pumps can be between 14-20 SEER. While heating, a heat pump’s efficiency is scored with an HSPF rating; Heat pumps can be between 7.7-10 HSPF.
Heat pumps paired with a furnace: Which does the most work?
It’s all about the thermostat. What the control will do is allow the heat pump to do the work for as long as it possibly can. Once the controller indicates that the heat pump needs to defrost - because it will freeze up if it gets too cold - it will automatically switch over to the heat strips in the furnace.
So the blower motor is going to be constantly blowing air around, whether it’s the heat pump, the heat from the coil, or the heat strips, and the controller will decide which element is doing most of the work.
In other words, the heat pump does the work first, and auxiliary (or emergency) heat takes over when the heat pump can’t do its job.
Can I manually switch between my heat pump and furnace for heat?
In the old days, the switch between heat pump to furnace was done manually. I still run into systems that are set up that way. With these systems, you would turn your heat pump on, and then if you thought the air coming from it was too cold, you would change the thermostat setting to emergency heat.
This would turn on the emergency heat until you allowed the heat pump to defrost. You had no idea if the heat pump’s heating mechanism was defrosted. It was 100% guesswork, which is why we don’t do it that way anymore.
Nowadays, the process is automated.
Can I use my furnace as the primary heat source and let the heat pump stay idle?
I don’t know why you would want to use a heat pump and a furnace that way, but I see it all of the time. It’s called ‘dual fuel.’ At any time, you could just use only the furnace for heat and only use the heat pump for AC.
If we’re going to recommend a dual fuel system, we suggest using the heat pump as the primary source of heat, and the natural fuel system powering the furnace will come in as the auxiliary.
If propane gets expensive, can I use the heat pump for my primary source of heat?
The main reason we run into this combination is if people have propane fuel instead of natural gas. Propane could be very expensive or cheap, depending on the current market, which is volatile.
So, if propane is really expensive that year, this allows users the option of using their heat pump as the primary source of heat and not using as much propane which is powering the furnace.
What if you have solar panels?
With solar, it’s incredibly cheap to run the heat pump as the primary source because it costs almost nothing in electric. The furnace comes on only if the heat pump has to defrost in very cold weather.
Why might I have to replace my heat pump along with my furnace?
The settings on the furnace fan need to match the available settings on your air conditioner, or the AC won’t function efficiently. This is also referred to as “rating” or “equipment matching,” and is a big reason why it’s often recommended that you replace your air conditioner and furnace at the same time. If not, they probably won’t work very well together because they’re not communicating well.
The number one misconception about heat pumps is that people say, “Well my heat pump is bad, but my air handler is fine. Or my air handler is bad, but my heat pump is just fine.” Too bad. They have to rate.
Most of the time, you’re going to have to replace them both. On a gas system, you may never have to replace them both, because they are mutually exclusive. But on an all-electric system, 99% of the time you replace them together.
The indoor coil and the outside condensing unit must be similar and must rate on the AHRI (Air Conditioning, Heating & Refrigeration Institute) in order for the warranty to cover them.
Why are heat pumps relatively rare in Columbus?
If we have a nice, mild winter, they work pretty well. If we have bitter cold, the heat pump will struggle. It depends on the weather, and it depends on the type of heat pump. If it’s a single-stage, low-efficiency system - with a rating of 14 SEER, 16 SEER - it’s not very efficient in the winter.
If it’s single stage, the heat strips in the furnace are going to have to basically come on when it’s near 40 degrees outside, which is not very efficient at all. It’s basically like a toaster oven, and you don’t want a toaster oven to heat your house. It’s very inefficient.
Why are heat pumps so popular in warmer climates?
The biggest reason is that electric systems are 100% efficient, so if you don’t have to contend with really cold weather in the winter, an electric system with the heat pump can satisfy 99% of the heat, 99% of the time.
So if you have a milder climate, where it’s not too hot and not too cold, you have a system that can be 100% efficient, and you don’t need a secondary heat source or a secondary cooling source.
Why do heat pumps not last as long as other HVAC equipment?
They will work all year round. Some people say my neighbor, my friend, my brother, their air conditioner AC lasted 15-20 years, no problem. Mine’s 12 years old, and I need a new one. What happened? Well, AC units work only three months out of the year. Heat pumps work all year round, which naturally leads to more wear and tear.
What is the cost of a heat pump?
The cost of a heat pump can range between $4,900 - $12,500. This range accounts for the cost of the equipment, labor, and other fees.
This range also covers a variety of system sizes and levels of sophistication, including variable-capacity heat pump systems.
The factors that can affect the price of your heat pump replacement include:
- Capacity/power of the system
- The HVAC equipment that you are either replacing or don’t need to
- Modifications to your existing system
- Line set protection
- Installation costs
- Tax credits and rebates
Now that you know the basics about heat pumps, both in terms of their construction and operation, you’re ready to take some next steps.
Below I’ve listed a few resources that you might find useful. I’d encourage you to continue to educate yourself as you approach your next big HVAC project. Knowing the reasons behind a decision can help you avoid common pitfalls in heat pump, furnace, or air conditioner AC installation and maintenance. It can also help you pick the best HVAC partner for your next job.
- How Much Does a New Furnace Replacement Cost in 2021?
- Cost of an Air Conditioner Replacement in 2021, a Complete Breakdown
- How Much Does a Heat Pump Cost to Replace in 2021?
- Fire & Ice Stories | Kevin’s New HVAC System
- SEER, AFUE and HSPF Ratings in HVAC: Why They Matter
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