Should finished basements be accounted for when considering the unit size?

[panaman]

Basically. I live in a ranch that is on a hill.
My Garage is in my basement. I also have 1/4 of the basement finished. Its about 300 square feet.

My house is a little under 1200 square feet.
I've had two quotes and both seem to think 2 ton heat pump, 2.5 ton air handler and say the finished room doesn't matter.
The finished room does have 2 heater vents in the ceiling.

here is a quick drawing of my basement



To me it seems like the finished room would count for some kind of heating and cooling usage.... granted it does stay nice and cool in there in the summer but it does get a little cold in the winter

[m kilgore]

Did either of the companies run a manual J load calculation. That is the only way to tell the true size you would need for your house. It would include the basement.

As far as basements are concerned there is usually not to much loss or gain depending on how much is sunk in the ground.

[beenthere]

That 300 sq ft won't add any cooling load.
It will add a little heating load.

Hopefully, teh garage is sealed off from the other rooms.

[panaman]

the left side is not sealed off...
But I am going to build an insulated wall right at the side of the stairs here in the next month (after i finish remodeling the baby's room)

Also. what is a manual J load calculation? The finished area is pretty much completely under ground... the ground slopes down toward the garage side.

[dac122]

Also. what is a manual J load calculation?

Manual J is a way to determine your heating and cooling needs in a more comprehensive way. It takes into account living volume; windows and door sizes and type; insulation values; walls; fireplaces; number of people in the dwelling; environmental extremes; homeowners preferred temps; etc. There were a number of ways they used to size units such as by just square footage or by what you already have.

I would ask every contractor to run this and have them show you their numbers.

Your intuition is correct, they should be taking this space into account. For cooling its not likely to add anything, but for heating it will add some.

[panaman]

I do have my work cut out for me....
My goal before october is to get that wall made, insulate my attic. And I want to insulate the ceiling in the garage part of the basement. because that part is drafty.

I did put in brand new windows through out the house and I got brand new glass block windows installed in the basement.