Supplemental heating is a necessity in many homes. For one, most central heaters aren’t powerful enough to maintain the right level of heat in every room. This may be caused by age or wear and tear, both of which can adversely impact a furnace’s BTU output.
Moreover, even where the central furnace is mightily powerful, it’s possible to have an addition (new room) that the ductwork doesn’t serve. Installing new ductwork to reach the new additions can be both expensive and time-intensive.
In both of these cases, a secondary heat source can be precious. Many people are choosing heat pumps are their supplemental heat sources, with ductless (also known as duct-free) heat pumps especially popular.
Read on to learn how the heaters work, their advantages, and whether a ductless heat pump is the right solution for your supplemental heating needs.
What is a Ductless Heat Pump?
To understand the ductless heat pump, you must know about heat pumps in general. The heat pump is a device that transfers heat from a source to what is known as a thermal reservoir.
They work in the opposite direction of spontaneous heat transfer, i.e., absorbing heat from relatively colder places and transferring it to warmer places.
Ductless heat pumps are a type of heat pump that doesn’t rely on ducts for transferring heat. They often contrasted with ducted models that require ductwork to transfer heat from one location to another. Ductless models function without typical ductwork.
For homes or additions without existing ductwork, ductless mini heat pumps can be an excellent heating solution. These appliances are also perfect where it’s impractical to install new ductwork systems or extend an existing one.
How Does a Ductless Heat Pump Work?
The ductless heat pump comprised two main parts – the indoor air handling unit and an outdoor condenser/compressor.
The indoor air handler is typically mounted high on the interior wall in the room where heating is desired. It directs heated air (or cool air (in the summer)) into your living space. Instead of a complicated duct system, a refrigerant line connects the indoor unit directly to the outdoor air handler.
As with all other heat pumps, the unit contains a substance known as a refrigerant that circulates through a cycle of evaporation and condensation. The compressor unit pumps the refrigerant between two heat exchanger coils.
In one of the heat exchanger coils, the refrigerant is evaporated at low pressure and absorbs heat from its surroundings. The refrigerant substance is then compressed en route to the other coil. Upon reaching the second coil, it condenses at high pressure, releasing the heat it absorbed earlier in the cycle.
The heat pump cycle is fully reversible. Thus heat pumps remain useful year-round. Also worth noting is that the ground and air outside always contains some heat.
This means that heat pumps can supply heat to the home even on the coldest winter days when temperatures dip below -18°C. Scientific studies show that air at such low temperatures still contains up to 85% of the heat it contains at around 21°C.
In addition to the refrigerant line, the outdoor and indoor units are connected with small electrical cables. The outside unit is placed outside of the home on the ground level. A small hole (usually three about three inches in diameter) is drilled through the wall to connect the two components.
Pros and Cons of Ductless Heat Pumps
We’ve already mentioned the all-year use (heating during the cold season and cooling during the hotter seasons). However, that’s not the only advantage of ductless heat pumps. Other advantages include;
- No need for expensive ductwork: The primary advantage over ducted heat pumps is that you don’t need to build expensive ductwork to transfer heat. Creating new ductwork alone costs $35 to $50 on average, so you can imagine how much you may spend to have a ducted system installed in a medium-sized room.
- Greater efficiency: Another major advantage over ducted heaters is increased efficiency. Ductwork systems, for all the advantages, are a massive source of heat loss. Some studies indicate that you may lose up to 20-30% of furnace heat through the ductwork. Ductless heat pumps eliminate the duct system.
- Excellent for supplementary heating: The heat pump is an exceptional choice for additional heating where the central furnace is at capacity. Such scenarios often call for the use of space heaters, hydronic heaters, and electric baseboards. Ductless heat pumps are a much more efficient solution.
- Possibility of multi-zoning: A category of heat pumps known as multi-split systems are designed in such a way that one outdoor condenser connects to multiple air handlers. This arrangement makes it possible to use a single heat pump system to heat multiple rooms at a go.
- Independent indoor air handler control: In the multi-split systems mentioned above, each air handler is fitted with a thermostat for individual control. The result is that you can control the temperature in each of the heated rooms individually.
- Flexible installation options: The indoor air handler, what you see inside the house, offers several installation options. Most of them are mounted on the wall, with a few LG models even designed to look like wall artwork. Meanwhile, others hang from the ceiling while a few install on the floor. This gives you all kinds of flexibility.
- Exceptional longevity: Finally, ductless heat pumps have a relatively long lifespan, with many units designed to last 15-20 years. The quality of the outdoor compressor, how much you use the heater, and the quality of maintenance will determine how long it lives.
Through a worthy consideration for supplementary heating in the home, ductless heat pumps have a few potential downsides, including;
- Expensive upfront: As a source of supplemental heat, ductless heat pumps are usually compared to space heaters and radiant heating panels. Ductless heat pumps are multiple times more expensive than these two options – even after you take out installation costs.
- They aren’t very powerful: Although heat pumps are incredibly energy efficient, they aren’t very powerful. Extracting more than 12,000 BTU of heat from the appliance is a monumental task. Yet, 12,000 BTU isn’t even enough for a medium-sized room if you’re using the heat pump as the primary heat source.
- Installation challenges: You might have heard some people mention DIY installation when discussing ductless heat pumps. It’s not that easy. Indeed, some manufacturers instantly void the warranty in case of DIY installation. That’s because the heat pump is a delicate system that requires professional installation.
Ducted vs. Ductless Heat Pumps
You’re likely wondering how ducted and ductless heat pumps compare. The main distinction between the two is the need for a duct system in ducted heat pumps.
Whereas ductless heat pumps let heat into the house via vents on the indoor air handler, ducted models comprise discreet ductwork installed in the ceiling. The ducts are connected to vents mounted on the ceiling through which warm air exits.
A key advantage of ducted heat pumps is that, except for the cents on the ceiling, every other component of the heating system is tucked away in the roof cavity and out of the house. Therefore, these units don’t take up any space in your living areas. They also don’t distract from the beautiful aesthetics of your home.
However, as mentioned earlier, substantial heat may be lost through the ducts. Unless adequately insulated, you risk losing up to 30% of all the heat destined for your house.
Ductless Heat Pump vs. Ductless Air Conditioner
A lot of people also tend to compare heat ductless heat pumps with ductless air conditioners. These two appliances are nearly the same. But, there are a few differences.
For one, the traditional air conditioners don’t provide heating, but heat pumps do. Working in reverse, the heat pump can extract heat from the air outside the house, even in extremely cold conditions, and transfer the heat into your home.
Secondly, heat pumps can also cool, meaning that the heat pump remains useful all year round. Meanwhile, air conditioners are only useful during the cooling season and must be paired with furnaces to become useful year-round.
Finally, although both can cool, the air conditioner is a much more practical choice for cooling than the heat pump.
The standard AC can remove the heat out of the home faster and much more efficiently than a heat pump. Indeed, heat pumps may need to be paired with ACs during the hot season for effective, whole-home cooling.
How Much Do Ductless Heat Pumps Cost?
It depends on several factors, including size, number of zones, and several other factors. However, the average cost of a single-zone heat pump ranges from $1,300 to $8,000.
Some models are slightly cheaper, even costing under $1,000, while others are much more expensive. A basic single-zone unit, for instance, costs about $700, while a 5-zone heat pump costs up to $13,000.
Installation is another cost to keep in mind. Although the installation process isn’t as complicated as installing a ducted heat pump, a licensed professional will still charge $500 to $2,000 for installation. You also need to budget for a concrete pad (about $125 on average) and a new electrical circuit ($200 to $500).
What is the Most Reliable Heat Pump Brand?
Many reputable brands make reliable heat pumps. However, the top options to consider are as follows;
- Daikin Heat Pumps
- Carrier & Bryant Heat Pumps
- Tempstar Heat Pumps
- Goodman Heat Pumps
- Maytag Heat Pumps
Top Factors to Consider when Buying a Ductless Heat Pump
If, after reading through the pros and cons of heat pumps, you’ve determined that you’d be best off with one of these heating systems, the next step is to learn what makes a great ductless heat pump. We recommend that you prioritize the following seven factors;
Heating Output (in BTU)
Obviously, the first thing you want to consider is the unit’s output. How much heat does it add to the room/home? one of the things to keep in mind include the fact that the smallest heat pumps are rated around 18,000 BTU (equivalent to about 1.5 tons) while the largest ones are rated around 60,000 BTU (equivalent to about 5 tons).
Ideally, you need about a ton for every medium-size space, i.e., 500-600 square feet if you’re using the heat pump as a secondary heat source. You may need more heating in a poorly insulated room or older home.
Ductless heat pumps guarantee greater energy efficiency compared to ducted units because they remove the need for ductwork. They also use very little electricity since there are no heating elements involved.
However, that doesn’t mean you shouldn’t try to find the most efficient model possible. Two efficiency metrics to consider are the Heating Seasonal Performance Factor (HSPF) and Energy Star certification. For HSPF, any value above 8 is good. A 10+ HSPF is excellent.
Single or Multi-Split?
We’ve already mentioned that there are single-zone and multi-zone heat pumps. Single-zone models comprise one outdoor unit and one indoor unit, whereas multi-zone heat pumps feature a single condenser unit and multiple indoor air handlers. Which one best suits your needs?
Essentially, you need just one indoor air handler if you’re looking for a supplementary heater for a single room. A multi-zone model is an obvious choice if you want to cover two or more rooms. However, you can also buy a multi-zone heat pump if it’s a single but very large room.
A key advantage of ductless heat pumps, as already mentioned, is the multiple installation options. While most indoor air handlers install on the wall, some can hang from the ceiling while others work from the floor. The choice is yours.
You need to know that wall-mounted air handlers are the most popular, followed by ceiling cassettes. The wall-mounted units range in size from roughly 30-44 inches wide, 12-14 inches tall, and 6-10 inches deep and are installed near the ceiling of an exterior wall. Ceiling models, meanwhile, are installed on the ceiling, often recessed behind a decorative grill that lies flush with the ceiling.
Yes, heat pumps are a little noisy. Even a brand new unit will produce a level of “noise.” Studies show that the standard ductless heat pump produces about 32 decibels of sound, which is almost equivalent to the average refrigerator’s noise.
This is way lower than window ACs that produce 43 decibels on average and quieter than the oscillating fan produces 38-50 decibels.
Picking a quiet is just half the work, though. To ensure quiet operation over the appliance’s life, proper maintenance is paramount. If you hear any unusual sounds, have the unit checked immediately.
Convenience features are controls and functions that make an appliance easier to use. For ductless heat pumps, the first thing you want to consider here is the remote control.
Modern heat pumps allow you to change temperature settings remotely without leaving the sofa. Indeed, check out for smart control, too, as this allows you to change settings via your smartphone over Wi-Fi.
Thermostats are another worthy consideration. Some heat pumps have built-in thermostats, while others come with a thermostat that you install separately on the wall somewhere. Finally, always look out for installation kits, including grills, as these make installation easier.
Finally, a great heat pump has a long warranty that covers a lot of possibilities. Many manufacturers offer a 10-year warranty. Some may offer a shorter warranty, often 3-5 years, on the compressor and a longer warranty, up to 10 years, on the air handlers. Others, meanwhile, offer a blanket warranty on the two parts.
Then, you have manufacturers that offer a labor warranty. Labor warranties are only applicable where the unit is installed by an HVAC professional approved by the manufacturer and typically run for 5-10 years. Some manufacturers require that you claim/register for the warranty.
How to Install a Ductless Heat Pump
Installing a ductless heat pump, though a delicate process, can be accomplished in an hour or two as long as you know what you’re doing. Assuming that you’ve ordered the right-size unit, here’s a step-by-step guide to install a single-zone, wall-mounted model;
- Mount the bracket for the indoor air handler to the wall room.
- Use a hole saw to cut a 2 5/8-inch diameter hole through the exterior wall.
- Insert the plastic sleeve through the hole you cut in step #2 above.
- Attach a plastic conduit to the outside of the house to conceal the electrical cable and refrigerant lines.
- Install the condenser unit’s mounting bracket to the exterior of the house
- Run the provided electric cable through the hole bored in step #2 and connect it to the air handler.
- Lift the air handler into its mounting bracket and feed the attached cables and refrigerant lines through the sleeve to the outdoors.
- Use the supplied screws to secure the air handler to its mounting bracket.
- From the outside of the house, connect the copper tubing to the two refrigerant lines.
- Grab the refrigerant lines and electrical cables and pull them through the plastic conduit down to the condenser unit’s bracket installed in step #5.
- Seal the refrigerant lines and electric cables by snapping the cover onto the conduit.
- Using a tubing bender, bend the copper refrigerant lines until they reach the condenser mounting bracket.
- Bring in an electrician to run a new circuit from the mains to the outside of the house right next to the condenser. Then, connect the electrical cable to the condenser as appropriate.
- Secure the condenser to its mounting bracket and connect the refrigerant lines to it as appropriate.
- Your heat pump set up is complete! Head inside the house and use the remote control or thermostat to operate the air handler.
Ductless Heap Pump FAQs
If you still have questions about ductless heat pumps, the following are answers to questions shoppers frequently ask;
Can a ductless heat pump heat the whole house?
The short answer is – YES. Although most ductless heat pumps are designed for small spaces, larger units from the likes of Mitsubishi are designed for whole-house use.
A small, 4-roomed house, for example, can effectively run on a 60,000 BTU 4-zone heat pump. The appliances work best as secondary heaters, though. Not primary heaters.
How many square feet does a ductless heat pump cover?
The standard ratio is one ton (about 12,000 BTU) for an average-sized 500-600 square-foot room. This figure doesn’t apply to all situations, though.
When calculating the required heating in BTU, it is imperative that you also consider other factors, such as the number of windows/doors in the room, the climate of the area, insulation quality of the room, ceiling height, and whether the room gets sunlight.
Does ductless heating add value to a house?
Yes! Installing a ductless heat pump increases property value. The exact margin of increase is difficult to tell. Some experts say your property value can increase by as much as 10%, while others believe a 100% return on investment is a more accurate estimate. The boom line, however, is that it increases property value.
Do ductless heat pumps work in the cold weather?
Yes. Heat pumps use the heat in the air or ground around them as the main source of energy. The air and ground only lose about 15% of the heat, even in extremely cold conditions. Therefore, the heat pump can still extract tons of heat, even in temperatures lower than -20°C.
Should I leave my ductless heater on all night?
Ideally, NO. The point of investing in a ductless heat pump in the first place is for energy efficiency – to save heating costs. Therefore, it beats purpose to leave it running overnight when you don’t need the heating.
The same applies when you’re not home during the day. Make sure to switch off the unit or program it to go off immediately after you leave the house.
The ductless heat pump is an exceptionally energy-efficient home heating solution and an excellent complement to the central furnace.
What’s more, with a multi-zone heat pump, you can supplement heating throughout the home without the need for portable space heaters. The best part – multi-zone heat pumps allow for independent control of temperatures in each room!
If you decide to invest in these heaters, though, you’ll need to get the sizing right. Otherwise, you may not raise indoor temperatures to your desired levels. Also, make sure to buy a very efficient heat pump backed by a solid warranty.