If your current HVAC system is getting old or it’s not working anymore, you’re likely
getting estimates for a new system from local companies like Fox Family Heating and Air.
It’s wise to get a few quotes from different companies around town. Just be careful. My
industry can be a little scandalous when it comes to salespeople telling you what needs
to be done for your new system to work correctly. One of the details I ask people when I come
out for a new AC installation is, how the air distribution around their house is. I’m
asking if there are any hot or cold spots in the house. Are there any bedrooms, offices,
or living areas that they would like to have more air to. I would say about 80% of the
people I ask say they’re just fine with the airflow they have. All the rooms seem
to be balanced just fine. Some people will say yes, they do have a problem
room and they would like to have better comfort in that room. In an effort to rack up the
price of your new HVAC system, salespeople looking out for their own commission checks
will recommend you spend the extra $5000 to 10,000 to change your ductwork to solve the
problem. Is that really necessary? I say no, not every time. Here’s why.
Ducts can be repaired individually. You don’t have to replace every duct in your house to
get better air to one or two rooms. Those rooms can have more airflow delivered to those
rooms by increasing the size of the duct leading to the room. Another way to get more air to
a room is to relocate the duct on the supply plenum to a spot that is more advantageous
for getting air there. Typically the end of the plenum.
You can fine-tune this processYou can fine-tune this process by cutting in manual dampers
that can be adjusted to decrease the amount of air going to one side of the house so that
it can be diverted elsewhere in your home. I still recommend a professional do this because
messing around with the ducts like this is the same as shutting down registers in your
home to get more air to another side of the house. This airflow disruption can cause high
static pressure, which can affect the more expensive mechanical parts of your air conditioning
system. The aerodynamics of the delivery system is essential to the longevity of the system
is all I’m saying, so unless you know how to check static pressure in the ductwork,
repairs like this should probably be left to the pros.
Your supply air ducts connect to your forced air unit, which is either in the closet, garage,
attic, or package unit on the roof. The air from that unit gets sent into a big box called
a supply plenum. Attached to that supply plenum are several ducts that lead to each room of
your house. Here’s how to tell if those ducts are in good shape or not:
• The ducts are strapped properly or lying on the floor of the attic.
• Those ducts are straight, not bent or kinked, restricting airflow.
• The duct’s vapor lining on the outside of the duct is not torn or melted.
• Good to decent insulation, which maintains the temperature of the air as it heads towards
the room that duct leads to. There’s not a lot more you can ask from
your ducts. If they’re adequately strapped, meaning each duct is straight or has long
sweeping bends (not kinks) that lead to where they need to go, and they have metal or vinyl
straps that secure them in place, that’s a good sign. Another thing that you’d like
to see for your ductwork is that the vapor lining, which is yellow, pink, grey, black
or silver, is in good shape. Ductwork has an R-value to insulate your ducts
to a set standard. 30 to 50 years ago, those standards were not as high as they are today.
So, ductwork has evolved in performance through the following stages:
• The yellow and pink is actually insulation. They may or may not have a clear wrapping
around them. This wrapping is the vapor lining. If you have this setup, the ductwork may be
original to the house, as it’s not too common to install them this way anymore. You can
expect this ductwork to be 30 to 50 years old. It has an R-Value of two (R-2). Not the
best in the world, but I’ve seen people keep it because it works just fine, and I
support them on that decision. • Grey ductwork typically has an R-Value
of four (R-4). Once again, not the freshest ductwork we see out in the field, but if the
ducts still meet those guidelines from above, people have chosen to keep that ductwork a
little longer. • Black and silver ducts can have an R-Value
of either R-6 or R-8. R-6 has been around for the last 25 years or so. R-8 is the newest
standard and has the thickest layer of insulation surrounding the inner lining.
I tell people your ductwork’s life averages about 30 years. Some people replace them every
time they get a new system, but most of the people I sell equipment to, don’t. That’s
because it’s impractical to do so. Yes, the higher R-value of the ductwork, the better
performance you’ll have. The ductwork will hold the hot or cold air it’s delivering
inside it better. That translates to cooler or warmer air to your rooms, depending on
which season it is. Your decision is whether you want to spend the extra money to change
your ductwork out every time you change your HVAC system. Hopefully, I have armed with
some useful knowledge going into your next project. Good luck!