13 Furnace in Attic Pros and Cons

The quest for more space causes homeowners to look beyond their traditional options when designing or remodeling a home. One of the latest talking points in this area is the installation of a furnace in the attic. When you have this unit in a space that you normally don’t use, then it creates more usable space in your living environment.

A furnace in the attic also costs less to install than other designs since the access point to it is usually through the roof. That makes cheaper to replace a broken unit while reducing the cost for repairs.

Because the furnace is in a space that most homeowners do not visit frequently, it is not unusual for an HVAC system in the attic to develop system problems that remain undetected for some time. There is even a higher risk of not changing the filters for the equipment because of its location.

If you are thinking about placing your HVAC system core at the top of your home instead of the bottom, then these are the furnace in the attic pros and cons to review today.

List of the Pros of a Furnace in the Attic

1. You can save a lot of space with a furnace in the attic.
Modern HVAC systems come with multiple components. Split systems are more popular than ever, which means part of the unit is outdoors and another stays inside to ensure that the hot air gets to each room. Because storage space is at a premium, having an entire closet dedicated to a furnace isn’t a great idea for some homeowners. There are times when putting the unit on the floor isn’t an option either. That’s why some systems are in the attic, despite the lower levels of energy efficiency that occur with this design.

2. It could save you some cash on the installation costs.
Forced air systems are usually the cheapest ones to install in homes today, and a furnace qualifies as this type of system. Heat pumps and ducts are part of it too. Since most homes have their HVAC system serve multiple functions at once, it can be cheaper to install the unit in the attic because the roof access can make inspections, maintenance, and repairs at lot easier. There are times when it gets placed in the attic because placing it there is the only thing that makes sense from a cost perspective.

The reason for this advantage is the fact that venting for your furnace requires less work in an attic than it does in other locations of your home. Unless you have a slab (where the equipment would likely be in the garage), venting can go directly through the roof instead of routing through an exterior wall, making it much easier to install the duct work along the upper floor.

3. A furnace in the attic is a design that works for all homes.
If you don’t have a crawl space or a basement, then it can be a challenge to place a furnace on the ground floor of the structure. You might not receive the same air movement benefits if the unit is in a garage either. When you place a furnace in the attic to take advantage of its downflow design, then you have a product which can work in any type of home. Because you are forcing the warm air downward to heat the structure, there are no issues of temperature wasting to worry about when operating the unit.

4. The cost profile for a furnace in the attic is competitive.
If you want to purchase a mid-efficiency furnace for your home, then the price profile for the equipment is similar with a downflow model compared to an upflow one. Expect to pay around $1,000 for the equipment, along with another $1,000 to install it for most geographic locations. Pricing can go up by 50% depending on the difficulty of the installation and a higher level of efficiency for the product. That means you can focus on finding the best possible furnace that meets your budgetary needs instead of being forced to pursue something that may not work well for your property.

5. There are multiple installation options from which to choose.
If you have a furnace in your attic, then you can install almost any type of equipment in that space without compromising your safety. Even gas furnaces work there when you have the proper venting and alarm systems available to ensure any leaks are detected quickly. When you can use natural gas over electricity, there is an opportunity to boost the efficiency rate of your furnace as well. If a high-efficiency unit can hit 90 with a typical installation, then you can achieve a rating of at least 65 with a standard installation.

You can eliminate the disadvantage of efficiency loss by finishing the attic before your installation. If that is too much of an expense, then some homeowners have create a small “room” for their furnace that is sealed off from the rest of the space to improve this issue.

List of the Cons of a Furnace in the Attic

1. It will lower the efficiency of your furnace.
The primary reason why furnace placement occurs on the bottom floor of a structure is because the warmer temperatures rise to displace the colder air. This process creates a cycle where the coldest air eventually makes its way to the unit so that it can be warmed up to move back upward once again. That is why it always feels a little cooler in the basement or first floor of a house while the upper floor becomes much warmer.

If you place the furnace in the attic, then you must install the infrastructure in the building to force the warm air to the bottom floor. That means you have higher energy costs and less efficiency since you’re blowing the air down instead of allowing it to rise naturally. The total drop in efficiency can be up to 35%.

2. You must maintain your air ducts at all times.
Even when your HVAC system operates in perfect condition, it will still lose up to 30% of the air that moves through the ducts. There are holes, leaks, and poorly connected vents that all work to rob your furnace of its overall efficiency. When you place a furnace in the attic of your home, then the hot air is already at its maximum level. That means you are heating the environment without benefiting from the cost or energy expenditure.

Since this also causes the furnace to run longer to make up for the displacement, your energy bills will likely increase if you decide to place your furnace in the attic.

3. It can damage furnaces which have a high efficiency rating.
Most homeowners should not place a condensing furnace in an unconditioned space because the unit will produce water as it heats the air. That moisture can freeze if it receives exposure to exceptionally cold temperatures. That means having it placed in the attic or a crawl space is a bad idea because you are increasing the risk of causing damage to the equipment. If your attic is finished and the HVAC system is in excellent condition, you might be able to avoid this disadvantage, but most houses do not have an attic that is suitable for full-time living.

4. Problems with the furnace can remain undetected for some time.
When the furnace is in the attic, then it can be easy to forget about the unit until there is something that goes wrong with it. Many homeowners operate on an out-of-sight, out-of-mind perspective, which means they don’t pay any attention to their equipment until a costly issue is already present.

You might not notice issues like a clogged condensate drain until you begin to see moisture overflow issues appear in your home. If there is too much water in your attic, then it might lead to mold in your insulation, floor joists that begin to rot, ceiling leaks, and fixture damage. None of these outcomes are things you want to have in your home.

5. The heat from an attic in the furnace doesn’t always feel comfortable.
Some homeowners find that the heat which an attic in the furnace provides is not always the most comfortable way to improve an indoor environment. Because the warmer air comes from ducts that are at ceiling level in each room, the unit creates a “warm air fan” experience where you feel the heat near your head first instead of down by your feet. Those who have never encountered that type of temperature change are often surprised at how it makes them feel since the top of your body gets warmer than the bottom half.

Depending on the temperature outside, this disadvantage might even make it difficult for the hot air to even reach your feet. Since it will start rising upon release into the home, you must have a distribution network along the bottom of the lowest floor to avoid this issue.

6. There are more installation requirements to consider with an attic in the furnace.
There are stricter regulations in place for most communities when comparing an attic in the furnace to one in a crawl space or basement. Your contractor cannot install this equipment on carpet directly. Tile is not an option either. There cannot be anything combustible around the unit either with the exception of the wood joists that support the structure.

Most homeowners discover that they must purchase a separate sub-base for their furnace with an installation in the attic because there must be a barrier between it and the floor to remain up to code.

7. It is a reflection that your furnace might be old.
Although it is common for an attic furnace installation to occur in some parts of the United States, this design is usually an older one that reflects a lack of knowledge about energy loss. We were more concerned about space than utility costs in the past, which is why many units went above the heads of homeowners instead of below their feet. If you own a home with this design or are thinking about purchasing one, then it is imperative to review the age of the equipment. You might discover that it is time for your property to receive an update.

8. This design requires more penetration into your home.
You must have more holes creating in your ceiling to install the duct work and move the hot air through your home if you opt for a furnace in the attic. This process is the only way that you can create a thermal envelope that can provide a comfortable indoor environment throughout the year. Since you need downflow action, there must be more transitions installed with this HVAC system option compared to upflow or horizontal units. Without them, the air would have no place to escape.

Verdict on Having a Furnace in the Attic Pros and Cons

The pros and cons of placing a furnace in the attic indicate that this idea is not a good one under most circumstances. Not only will it interfere with the efficiency ratings of your equipment, but it can also cause damage to your unit that may go undiscovered for some time. That means the outcome could be costly for your HVAC system, your home, and even your health. Choose attic placement only if there is no other option.

If you already have an HVAC system in your attic, then the most important thing you can do is change your filters regularly. That means someone needs to climb up there a few times per year to put them in to help your indoor environment. Then have a qualified contractor review your insulation and sealing to maximize the efficiency of your unit.

The other option you have is to convert an unfinished attic to a finished one to prevent heating losses. That might give you even more space to use.

About the Author
Brandon Miller has a B.A. from the University of Texas at Austin. He is a seasoned writer who has written over one hundred articles, which have been read by over 500,000 people. If you have any comments or concerns about this blog post, then please contact the Green Garage team here.