How To Effectively Heat & Cool A Bonus Room Above A Garage

If you have a bonus room above the garage, there are plenty of potential uses for it. You may want to turn it into an exercise room. You may want to turn it into a home theater. You might also be thinking about turning this room into an additional guest room.

Unfortunately, there is a problem you might run into. It can be very difficult for you to control the temperature in this room. During the summer, the room can feel like a sauna. Then, during the winter, it might feel like you are standing outside in the middle of a blizzard.

This can be frustrating for you and everyone else who uses the room. Why is this room so difficult to control, and what can you do to address the problem? There are several important points to keep in mind.

Why The Room Above the Garage Has a Variable Temperature

A bonus room with a pool table in it
A bonus room with a pool table in it

There are several reasons why the room above your garage has such a varying temperature range. Some of the most common reasons include:

  • No Insulation: When a house is being constructed, a lot of builders do not use enough insulation in the room above the garage. Construction companies are always looking for ways to cut costs. They often feel like people are not going to spend a lot of time in the bonus room, so they do not give it enough insulation. As a result, the temperature swings in the room about the garage can be drastic.
  • Air Leaks: There might also be a significant air leak in the room above the garage. For example, you might feel a draft somewhere in the room. The air can leak more quickly from this room because the temperature difference between your bonus room and your garage can be significant, particularly because your garage is probably not insulated either. This means that your bonus room does not do a good job of holding air conditioning or heat.
  • Not Enough Ductwork: Furthermore, you might have a hard time controlling the temperature in the room above the garage because there is not enough ductwork. The vast majority of HVAC contractors do not spend enough time installing ductwork in the bonus room. This is a relatively large room, probably bigger than most of the bedrooms in your home. On the other hand, it might only have a single segment of ductwork, which is why you have a difficult time keeping the temperature steady.
  • Distance to the HVAC Unit: The room above the garage might also be located a long way from the HVAC unit. Where is the furnace located in your home? Is it located on the exact opposite side of the building? If so, the room above the garage is always the last one to receive the heat or air conditioning from the HVAC unit. This could be the reason why the room is always hot or cold.

For all of these reasons, the room above the garage may have a temperature that swings back and forth wildly. Therefore, it is important for you to think carefully about how to solve the problem.

How To Heat and Cool a Room Above the Garage

If you want to find a way to more effectively control the temperature in the room above the garage, you have several options available. Some of the choices include:

Seal the Leaks

The first thing you need to do if you want to heat and cool a room above the garage is to see all the leaks. You have plenty of heat and air conditioning flowing into the room, but the problem is that it keeps flowing out.

You should try to figure out where the leaks are coming from and put a stop to them. There are several places you may want to check, but you should start with the windows and doors. There are simple instruments you can use to figure out if there is a leak. Then, you may want to use something to seal the leaks and stop the flow.

The biggest benefit of this option is that it is relatively quick and inexpensive. You may also notice an immediate difference in your utility bills because the temperature should stop fluctuating so much. The downside is that you may not be able to catch all of the leaks, particularly if the heat and air are flowing directly through the floor into the garage. If you really want to put a stop to this, you will need to get a bit more involved.

Add More Insulation

Insulation in a Wall
Insulation under a floor

One of the top options is to add more insulation. You may want to have an HVAC contractor come back to the home to take a look at the room above the garage. They can figure out what parts of the room are insulated, what parts of the room are not, and what you can do about it.

There is a good chance that most of the air leakage from the room above the garage is going directly into the garage because the garage is probably not heated or cool. Therefore, you need to find a way to stop air from flowing out of the bonus room and into the garage. Installing more insulation between the room above the garage and the garage itself is one of the best ways to do this.

There are a number of benefits that come with taking this approach. It is straightforward, effective, and it should be relatively easy for you to find a contractor that can do this. Or, if you have experienced adding insulation to your own home, you may be able to do this without asking the contractor for help.

On the other hand, you may need to rip up the entire floor if you want to add more insulation. Depending on the type of insulation you use and the floor you have, this can be very expensive.

You should think about this, along with the other options available, before you decide if this is the right option for your home.

Add More Ductwork

Ventilation/aluminum pipework in a loft space
Ventilation/aluminum ductwork in a loft space

Another way you can deal with this problem is to add more ductwork to the home. Again, if you want to do this, you will need to rely on an HVAC contractor who can help you. You may not even know exactly how much ductwork is present throughout the room. If the attic is above your bonus room, you may want to climb up there to take a closer look at the ductwork to your attic.

If you call an HVAC contractor to help you with this issue, you should ask them to perform a Manual D Calculation. This is a specific type of calculation they need to perform to figure out how much ductwork you need in the room and how you should lay out the ductwork itself.

A lot of HVAC contractors don’t do this calculation because it takes extra time, but it is important if you want to place your project in the best position possible to succeed.

The biggest benefit of adding more ductwork to the room is that you will have an easier time controlling the temperature. The downside is that this will not necessarily solve your air leakage problem.

As a result, your utility bills may go up because your HVAC system is simply going to be pumping more air conditioning and heat into a room that is leaking air. In addition, adding more ductwork can be expensive as well.

Even though this might make you more comfortable, it can also be more expensive.

Use a Portable Air Conditioner or Space Heater

If you don’t want to go to the trouble of ripping up your bonus room, then you may want to add another heating or cooling device specifically for the bonus room. During the winter, you may want to use a portable space heater.

All you have to do is plug it into the outlet and let the space heater go to work. Importantly, you need to avoid using something that requires gas indoors. Otherwise, you may experience carbon monoxide poisoning, which can be incredibly dangerous.

During the summer, you may want to use a portable air conditioner. The best way to deal with this is to install the window unit. Essentially, you will open the window, put the air conditioner inside, and slam the window shut. Even if you have central air conditioning, this may be something you want to consider if your HVAC unit is not getting the job done.

There are several benefits that come with this approach. This is one of the cheapest options available because you do not have to worry about ripping up your bonus room to solve the problem. All you have to do is purchase a space heater or a window unit, plug it in, and go to work.

The downside is that this solution can be noisy. Portable space heaters and air conditioners can be loud, which may make it difficult for you to hear what other people are saying. Furthermore, they take up a lot of space in the room, which means they might get in your way.

Use Ductless Heating and Cooling

Another solution to the issue is to get away from ductwork altogether. For example, you may want to go with ductless heating and cooling. This is an advanced heating and cooling solution that could be a permanent solution to your concerns.

A lot of traditional heating and cooling methods use a single zone; however, the problem with this is that the bonus room is unlike any other room in your home. The room above the garage is prone to significant temperature fluctuations, so you need to create a new way to deal with the problem.

With a ductless option, you can create a separate area for the bonus room, making it easier for you to control the temperature. The biggest benefit of this option is that you do not have to worry about the temperature fluctuating, as this is one of the best ways to keep the temperature in the room constant.

The downside of this option is that it is very expensive. You may need to pay a few thousand dollars to hire a professional to install this option for you. This option can help you save money on your utility bills, so it may eventually pay for itself; however, it can take several years for this to pay off. You may want to talk to a professional about a ductless heating and cooling option.

Frequently Asked Questions About Heating and Cooling a Room Above the Garage

Some of the most common questions people ask about heating and cooling a room directly above the garage include:

Is the room above the garage usually connected directly to the HVAC system?

If your house has central heating and air conditioning, then the room directly above the garage should already be connected to the HVAC system. Therefore, you should have some degree of control over the temperature in that room. On the other hand, a lot of HVAC contractors do not use enough ductwork above the garage, which could create problems.

How come I have a hard time keeping the temperature steady in the room above my garage?

The biggest reason why you cannot keep the temperature steady is that there is not enough insulation in the room. Because your garage is probably not heated or cool, the air directly above the garage flows down into the garage, leading to significant temperature changes. You will need to add more insulation to stop this flow.

I have heard that using ductless heating and cooling is an option for a room above the garage. Is this a good idea?

Yes, this is an option you may want to consider for the room above the garage. Even though it can be very expensive to install, it can also dramatically reduce your utility bills, allowing you to save money over time.

About Charlie D Paige

Charlie is a massive DIY fan, with dozens of DIY projects under his belt - ranging from tiling to electrics, and concrete pads to walls. Charlie loves tinkering, seeing how things works, the outdoors and playing with power tools... so is it any wonder that he's completed so many DIY jobs over the years?

Charlie loves spreading his hard-won DIY experience with the world via this blog.