Barndominiums are cheap to build, can be customized more than traditional homes, and work well in all environments. However, they can get quite hot due to the metal roofing, so you’ll need to install ductwork for central air conditioning. But how do you properly install ductwork in a barndominium?
To run ductwork in a barndo, you’ll need to survey the barndominium and choose the best positioning system for the ductwork. You can build a ductwork box from wood or metal before installing the ductwork. Insulate the ductwork thoroughly, seal it completely and ensure the ideal air distribution.
This guide will detail the steps to run ductwork in your barndominium. I’ll cover everything you need to ensure the ductwork is properly insulated and operates efficiently. After covering the process of running ductwork, I’ll give you tips on choosing the right air conditioning system for your barndominium.
1. Survey Your Barndominium
Most barndominiums don’t have pre-installed air conditioning systems as they are usually converted from older structures. The metal roof and poor ventilation systems don’t make installing ductwork any easier, and you’ll have to choose the right spot for your ductwork.
Another thing to consider is that barndominiums don’t have large attics and many won’t have insulated attics. This means you’ll have to install the ductwork along the walls and insulate them from the inside to retain cooling efficiency.
When surveying your barndominium, check for specific areas where the ductwork can be installed. Measure the space inside the attic (if your barndominium has one) or measure the exact length required to install the ductwork along the walls. Don’t settle for rough estimates, as you’ll need exact measurements when building the ductwork boxes.
Another crucial factor to consider is the ventilation systems already present in the barndominium. For instance, some barndominiums have roof ventilators to remove hot air from the building. If your building has modern ventilators, they can be sealed with a switch. If the ventilators always remain open, you’ll have to seal them.
However, remember that this may cause overheating inside the barndominium when the central cooling system is switched off.
If you aren’t sure of what to look at when surveying your barndominium for ductwork installation, have a professional survey it for you. If you plan on installing the ductwork yourself, they’ll probably charge a consultation fee, but you’ll then have a better picture of what you need to fix the ductwork properly.
2. Build or Order the Ducts
Once you have all the required measurements, you can start building the boxes for the ducts. Aluminum or tin is usually used to build ducts, but these can be unsightly if you’re installing the ducts along the walls.
Wooden duct boxes are a better option for barndominiums, and you can easily build them with some DIY carpentry experience. Before building wooden ductwork, always consider these factors:
- The ducts should be big enough for additional insulation and the duct trunks and still have some space for ventilation.
- Use quality water-resistant wood for duct boxes since they are more exposed to roof leaks.
- Use longer planks to build a single ductwork box and limit the joints as much as possible.
- Always double-seal the joints (to minimize energy loss in case the ductwork piping gets damaged).
This process will likely be the most time-consuming step, but it’s worth the effort, especially if you want to keep up the aesthetic appeal in your barndominium’s interior.
Alternatively, you can get pre-built metal ductwork boxes, which are unsightly and will negatively affect your barndominium’s interior look. Besides, wood is more stable than the thin metal boxes that come with modern ductwork, and it’s less likely to need repairs.
3. Make Spaces for the Airflow in the Ductwork
Once you’ve installed the outer ductwork structure, you can start cutting holes in the ductwork to make space for the cold air to flow through the barndominium. However, you’ll have to carefully choose where to place the openings to maximize airflow and cooling efficiency. The last thing you want is to cut unnecessary holes in the ductwork only to seal them afterward!
While HVAC professionals can tell how many air vents are needed in a room by looking at the room’s size, it’s best to measure the room’s area for more accurate results. HVAC professionals recommend installing 1 air vent in rooms smaller than 100 square feet and 2 vents in larger rooms.
Additionally, try to keep the air vents smaller to maximize cooling efficiency and reduce energy wastage. If you can’t change the air vent size, you’ll still have to ensure that the vents are no bigger than the ductwork’s width.
4. Install the Supply Trunks
Supply trunks or duct trunks form the main structure of your ductwork system. They are usually made from galvanized steel or flexible aluminum and do a great job of keeping cool air in. Thicker supply trunks are usually more efficient and suitable for barndominiums with more space for ductwork.
While you can build your own duct trunks, I highly recommend ordering them from an HVAC parts supplier since they require welding experience and can be difficult to build. When you get the duct vents, check that they are completely sealed and inspect the areas along the box joints.
Once you have the supply trunks cut to size, you’ll have to create the vent holes based on the vent box design. Be extremely accurate with your measurements since the duct vents must fit the duct boxes perfectly.
Always tape all seams and any areas where you penetrate the duct trunk. Use special waterproof duct tape and add two layers of tape if necessary.
When you’re done with installing the supply trucks, complete this checklist:
- Do the supply trunks fit perfectly in the duct boxes?
- Is there enough space around the supply trunks for air circulation and insulation?
- Are the seams and edges of the supply trunk thoroughly sealed?
- Do the air vents fit perfectly in position?
If something is out of position, there’s no need to panic. Most duct trunks can be modified, and you can easily make them smaller if needed. However, always take special care to seal the seam along the trunk to ensure that it remains airtight.
Even a small crack can significantly reduce your air conditioning system’s efficiency, and it’s often hard to detect these leaks!
5. Install Duct Insulation
While ductwork insulation may not be needed in attics that are already insulated, they are essential to preserving your ducts in a barndominium. If you live in an area where summers are hot, it’s better to always install duct insulation for better air conditioning efficiency.
Duct insulation can also make the ducts soundproof and prevent the ducts from “sweating.” If left uninsulated, water may condense on the duct trunks, causing the wooden box or ceiling to get wet. This can be especially damaging in a barndominium where the ceiling is usually thinner or made from wood.
You’ll have several options to choose from for duct insulation, but I recommend getting duct wrap since it’s easy to install, and you can always repair it if it gets damaged.
Some types of duct wrap insulation include:
- Mineral wool duct wrap: Mineral wool is a great insulator thanks to its open fiber structure and ability to trap air pockets. It’s also one of the cheaper insulation options.
- Elastomeric foam insulation: If you’re looking for insulation that has effective moisture resistance and will prevent your ducts from “sweating,” this is an excellent option.
- Nitrile foam insulation: This rubber foam insulation is also ideal for ductwork and has good moisture resistance. It’s also one of the more flexible ductwork insulation options.
You can also install ductwork insulation panels, but I don’t recommend these in a barndominium, especially if your ductwork isn’t all straight. Insulation panels work better in large warehouses or commercial buildings where there aren’t many turns in the ductwork.
I also recommend reading my guide on condensation in barndominiums. You’ll learn why the phenomenon occurs and how you can prevent it. You’ll also find out how water seepage can affect your structure.
How To Install Ductwork Insulation
Once you’ve selected the ideal insulation option for your ductwork, you can apply it to the duct trunks. Always ensure that there’s enough space for the ductwork insulation, and adjust your duct trunks if necessary.
You should ideally have a few inches around the insulated ductwork for efficient airflow.
Follow these steps to properly install ductwork insulation:
- Choose the right duct insulation thickness. The ideal range is 25mm-30mm, although you can install thicker insulation in colder areas.
- Clean the duct trunks thoroughly, so the insulation works well with the adhesive.
- Apply adhesive and wrap the ductwork with the insulating material, taking care not to exceed the maximum insulation thickness.
- Secure the duct wrap in place with insulation wires and use aluminum tape if necessary.
- Install the insulated duct trunk in the duct boxes and check that there’s enough space around the ductwork for effective airflow.
Check out this YouTube video for more details on how to insulate ductwork:
Ductwork insulation will usually last a decade at the very least, so install it properly and double-check for damaged areas.
6. Seal the Ducts Completely
Once you’ve installed the duct insulation and the duct trunks are in position, you can now seal the ductwork completely. Ensure that the duct openings are in position with the air vents and connect the ductwork to the HVAC system.
If you have experience with HVAC systems, then you’ll know how to check for air leaks in the pipe joints and areas where the ductwork is connected to the HVAC. Once you’re satisfied that there aren’t any leaks, you can test your central air conditioning system.
Remember to seal all open points in the barndominium after installing an HVAC system. Take special care to seal the area around the windows, under doors, and in other areas where warm air may enter the building.
7. Use Additional Temperature Control Systems
Barndominiums usually have metal roofing and aren’t usually fitted with natural insulation. While a regular air conditioning unit will work fine in a modern home, you may have to use other air cooling options along with a central air conditioning system to reduce energy costs in your barndominium.
Some of these options include:
Roof Ventilation Systems
Roof ventilation is crucial in barndominiums since they don’t have the most energy-efficient roof design. Ideally, you’ll need escape vents in your roof for hot air to escape, especially when you’re not using the HVAC system.
I recommend getting a roof ventilator that can be completely sealed in the winter or when you want to turn on the central air conditioning system.
Insulating Your Barndoninium’s Walls
While most of the heat enters and escapes from the barndominium’s roof, insulating its walls will also improve the building’s energy efficiency, and you’ll have to rely less on the central air conditioning system.
Wall insulation options include spray foam insulation, blanket insulation, and foam board insulation. Spray foam is easiest to apply, but board foam insulation is more durable.
When insulating a barndominium’s walls, try to use insulation with an R-value of 20-25.
Adopting an Open Floor Plan
Barndoniums are usually spacious, so don’t stuff them with unnecessary furniture and appliances. Less congested rooms have better airflow and won’t get too hot, reducing the need for central air cooling.
Choosing the Right HVAC Model
Not all HVAC systems will work in a barndominium, and choosing the right one is crucial to maintaining an energy-efficient system. Installing an HVAC that’s too large is a waste of money and energy, and installing one that’s too small will reduce heating and cooling efficiency.
Make sure you install an HVAC unit with a SEER rating of at least 14 or above since AC units with higher SEER ratings are more energy efficient.
Final Thoughts
Installing ductwork in a barndominium can be challenging, especially if you don’t have an insulated attic. You’ll need to build a duct box for the duct trunk and ensure the ductwork is properly insulated.
While proper ductwork will affect the energy consumption of your HVAC unit, insulating the barndominium’s walls, adopting open floor plans, and choosing the right HVAC unit will reduce your energy bill and reliance on the central air conditioning system.
