What Size AC Unit Do I Need?

"A house expands and contracts as it heats so you have to account for air loss when the wind blows, a house becomes leaky."  

- Brandon Day, Daycool Heating & Air

 

On the Check A Pro Radio Show today a listener called in with the following question - "What Size AC Unit Do I Need?"

So another great question.  Here to answer that question is a heating and air conditioning expert, Brandon Day from Daycool Heating & Air.

For more information about Daycool Heating & Air in Mobile, AL -  log on to www.daycoolair.com or check them out at www.checkapro.com.

 

Visit Us At -  www.daycoolair.com

 

Episode Transcript

(00:01):
A question that comes up a lot here on the Check.
A Pro Radio Show is,
how do I know what size air conditioning unit I need for my home.
I hear 3 to 5 ton,
I hear,
you know,
multistage this and yada,
yada ya,
you know,
how do I know you got to call an air conditioning expert?
I've asked Brandon Day to join me from Day.

(00:23):
cool heating and air.
Hey,
Brandon,
how you doing,
buddy?
How are you?
I am living the dream.
Thank you so much.
OK.
Simple question.
Which may not be so simple is what size air conditioning unit do I need?
How do you answer that question?
It's not straightforward.
There's so many variables.

(00:44):
Um No house is the same.
No,
home is the same building is the same.
Um You know,
depending on how many square foot your home is just off of.
Basic math is not gonna require the,
the same size unit for everything.
Newer homes are so well insulated and sealed.
Uh You have certain times that it's best to put a variable speed piece of equipment and uh that sometimes that wouldn't save you any money.

(01:13):
Uh or depending on what you're with your value point or your,
how much money you want to spend on something will dictate variable speed stuff,
which would dictate size.
Yeah.
You know,
one of the misconceptions is,
is,
you know what I'll get the biggest one I can afford because that's gonna cool my home better and you and I know better,

(01:40):
you're gonna have all kinds of problems.
One of it is probably high humidity in your home.
Explain why it's so important to size that ac unit.
Well,
you gotta essentially think of it this way.
You're trying to remove droplets of water out of the air in our climate.
That's the main concern.
Uh,
if you have a unit that's running too short of amount of time because they got the temperature right in there.

(02:03):
Humidity is still floating around there.
But it satisfied the temp unit's gonna shut off because it's so big.
It's like having a big block motor and a,
uh,
import little car.
That's,
that's too much for,
for something that doesn't need.
You can't,
you can't utilize it.
You have with brakes that aren't good enough on that small car.
Right.
Right.
That's a,

(02:23):
that's a better analogy.
But the,
uh,
so you want something that's gonna run to the right temperature and like when you size piece of equipment you have a,
a temperature,
it has to be able to achieve and hold her code,
uh,
by where you live and that you have to.
So,
when you're doing all the math,
you have to do it to that set point,

(02:44):
uh,
which dictates there,
there's so many scientific numbers that go into it.
But that's the gist of it.
You want it to run a little longer.
So,
people,
people don't understand that a lot of times.
Yeah.
So it's,
it's not like an engine because we have seen vehicles,
trucks and cars where someone will put in a big engine and yes,
that car will go faster,
but you have to modify some other things when it comes to your air conditioning system.

(03:07):
And I know this,
it's,
it's,
it's really critical,
it has to be sized properly and there is mathematical formulas that you have to put into place.
Something else that people don't understand either.
Brandon,
is that,
why can't I keep my house cool in the summertime when I have 35 people in it for a party because it's not designed it,

(03:31):
you know,
it's not designed for that.
Right.
It's designed for so many inhabitants.
So what happens?
It's all that body heat,
right.
Yep.
Or it's the same ideas.
People that have 50 computers in a house that's designed for one or,
or,
you know the code,
I,
we'll say code.
But if you're talking about whatever,
um,
it's designed for normal living conditions and if you're gonna have an event at your house once a year,

(03:55):
obviously you wouldn't wanna size something too big just because you're having an event one time.
Whereas a church would be sized different for the same square footage as it would.
If it was a home,
it would be,
the church was gonna require more um heat removal,
humidity,
removal,
et cetera,
et cetera.
Absolutely.

(04:16):
So to,
you know,
put this um into simple terms,
everybody,
let's say that that you have a five bedroom house and um you have three kids and they all leave home because they were grown up.
Your house may start to feel more comfortable now,
not just because the kids are gone,
but because there's less body heat in the house,

(04:37):
right?
Because the equipment hasn't changed,
but there's less things putting off heat,
not to mention there's less light bulbs on less TV S less computers and it really comes down to it being that,
um,
scientific,
it can be that sensitive.
So you need to call Brandon and his team out to actually run the numbers.

(04:59):
Um,
now,
generally what happens if,
if your house was built correctly,
everything was installed in size correctly.
But Brandon,
another question here.
Have you been to a home that was built by a builder where the AC systems were not sized right to begin with and you had to make a change.
Yeah.

(05:19):
Well,
another thing to take into account as well is when,
uh,
equipment,
when a home is,
is of some age,
it deteriorates all the building materials of our value,
which is insulating value.
All that matters,
house gets expands and contracts as it heat that so you have to account for,
for air loss when the wind blow,
you know,
a house becomes leaky.

(05:40):
We do blower door test where we can,
uh,
see how leaky a home is.
We can seal a home,
we can do the same thing with duct work and that all matters.
I mean,
like the people go,
well,
it's been leaking forever.
It doesn't matter.
Well,
what's the point of having a box here with the trunk that's supposed to deliver it here if it's leaking all the way to where it's trying to get there.
And that's the easy thing to the real.

(06:02):
Yeah.
It's like anything else.
Everybody,
it's like a diet.
It's like exercise.
Just do the right things and everything will run much better.
Brandon.
Thank you so much for joining me here today on the program.
Much appreciated.
Thanks for having me.