Although both a furnace and a ductless mini-split system can be a good option for heating your home, each one is generally a better fit for certain situations. If your home already has an existing central HVAC system, you are definitely better off going with a furnace. On the other hand, a mini-split is ideally suited for rooms or entire buildings without central heating, and these units can also be a great choice if you need to supplement your existing heating.

It would generally never make sense to switch from one type of unit to the other. This is especially true if your home doesn’t already have an existing ductwork system. However, if you’re planning on building a new home or completely renovating a building, then either a furnace or a mini-split can be an excellent option depending on how much space you have available. With that in mind, here is an overview of the different space requirements for furnaces compared to mini-splits.

How Much Space Is Needed for a Furnace?

Even the largest, most powerful furnace won’t take up all that much space on its own. Instead, it is the ductwork that has a much larger overall footprint. If you have a single-level home, the ductwork will typically run underneath your floor in the crawl space or above your ceilings in the attic. For homes with a basement, the ductwork usually runs inside the basement ceiling underneath the floor on the main level of the building, and this will obviously take up more room.

A new furnace will typically be a maximum of 2 feet wide, 2.5 feet deep and 3.5 feet tall. You also need to calculate for the air handler where the furnace blower is located, and this will also typically be around the same size as your furnace.

Even though furnaces aren’t all that big, they also require additional empty space around the front and side of the unit for clearance. This clearance is primarily for safety reasons to ensure that no walls or objects are close enough to the unit where they could create a fire risk. However, the clearance also helps to improve the unit’s performance by ensuring it has adequate airflow. Having enough clearance in front of a furnace is also important for ensuring that it can easily be worked on.

The general rule is that you should have at least 30 inches of empty space between the front and sides of a furnace and any walls. While 30 inches of clearance is usually sufficient, you may still want to leave a bit of extra space if possible. This is because the more clearance the furnace has, the more efficiently and effectively it should operate. If your furnace doesn’t have sufficient clearance, there won’t be enough air flowing around it, and the unit may start to overheat.

How Much Space Is Needed for a Mini-Split?

Mini-splits have a much smaller overall footprint compared to a furnace and ducted central heating system. Compared to having both central heating and air conditioning, a ductless mini-split will take up even less space since these systems can both heat and cool.

Although the condenser or heat pump part of a mini-split system can sometimes be almost as large as a furnace, this unit won’t take up any space in the home as it sits outside the building. However, the unit will require a concrete pad that is large enough to support its weight unless it is mounted directly on the side of the building or on the roof.

The indoor air handler part of the system will take up some space, but these units are typically mounted high up on a wall where they’re out of the way. Depending on where the air handler is located and the layout of your home, it may also be possible to recess the air handler inside your ceiling. In this case, the unit won’t take up any space in the room, and all you will see is a vent similar to what you’d find in a ducted central heating system.

If you plan on heating your entire home with a mini-split system, it will take up additional space since you will typically need to have one air handler unit in every room or large space. This type of system will generally also have a larger outdoor heat pump unit compared to a mini-split system with only one air handler.

In mini-split systems with only one or two air handlers, the outdoor heat pump unit will typically measure somewhere around 3 feet wide, 1 foot deep and 2 feet tall. However, if the system is powerful enough to run four or more air handlers, the outdoor unit will likely be closer to the size of a central AC unit.

The air handlers themselves are also fairly small. Most mini-split air handlers are only around 2.5 feet wide and 1 foot tall. Unless the unit is recessed, it will also stick out around 9 inches or so from the wall.

Although the different parts of a mini-split system are all fairly small and don’t take up much space, the main reason why these systems have such a smaller footprint than a furnace and central heating system is that mini-splits don’t need any ductwork.

A mini-split system is quite similar to a central AC or heat pump system in that it works by using refrigerant to remove or add heat to the air. The primary difference is these central systems have one central air handler whereas mini-split systems have individual air handlers that supply hot and cold air to each room.

How Large of a Space Can a Furnace or Mini-Split Heat?

How many square feet of space a furnace or a mini-split can heat effectively depends on how many BTUs the unit produces. Calculating how many square feet a furnace can heat is quite easy since the unit works to heat the entire home at one time.

With mini-splits, it is a bit more difficult as you need to look at both the total BTUs the outdoor heat pump unit produces and also the BTUs for each air handler. For instance, a 5-ton 60,000-BTU mini-split should be able to effectively heat around 3,000 square feet of space.

However, each air handler will only be able to heat a certain amount of space on its own. For example, a 5-ton mini-split may have five separate 12,000-BTU air handlers, each of which should be able to sufficiently heat a space of around 600 square feet. Although, you may also find a 5-ton system that has three 12,000-BTU air handlers and one larger 24,000-BTU air handler. In either case, these systems typically wouldn’t be sufficient for a 3,000-square-foot home since you will usually need one air handler in every main room and bedroom.

Boise’s HVAC and Plumbing Professionals

At Express Plumbing Heating & Air, we are proud to be one of the top-rated HVAC and plumbing companies in the Boise area. Whether you’re looking to install a furnace, mini-split or any other type of heating or cooling unit, our technicians can help you determine what type and size of unit you need. We’re also here to assist with any of your heating or cooling repair and maintenance needs or if you need any residential plumbing services. For more information, give us a call today.

Brad Jordan

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