How do I measure the square footage to be heated and cooled in an A-frame house?

Question

I am getting estimates on replacing my furnace and adding central air conditioning to my home. The slanted walls in my home pose a problem of how to measure the square footage to get the correct size furnace and air conditioner unit.

Answer 1

Just measure your square footage W x L. The slanted ceilings wont make that much difference. You don't walk around on your ceilings. Cold air will fall and hot air will rise so I would install ceiliing fans also to blow the hot air back down. m

Answer 2

Square footage would be the width times the length of your rooms. Cubic footage would be changed if you have vault ceilings, etc. Are the ceilings high or are you talking about rooms that have slanted walls imposing into them? (In other words, do the slants make the rooms larger or smaller?)

If you want cubic feet, you'll have to find the angle to get the exact measurements. If the wall is about the same length from the beginning of the slant to the top as it is from the floor to the beginning of the slant, I'd just estimate it's a right angle. Then you could take whatever your cubic feet for the regular part of the room is and multiply by 1.5 (add half your cubic feet to your figure from the room)

Answer 3

Careful measurement would suggest the method of cubic volume. Square footage estimating must assume eight-foot ceilings, if there are high ceilings you should correct for that. But in the usual A-frame, the area under the mezzanine that has flat ceiling, count as whole floor area; the space in the loft, and other parts under the slanted wall count as half the floor area.
Try a cubic volume estimate and see if the recommendation is in the same ball-park.

Answer 4

Here ya go buddy. Here's a rule of thumb.
You are looking for heating.
Homes sq. ft x height if it is different in some rooms figure them out individually. Take total volume from equation above and multiply by 3(if you have really good insulation,5(if you have moderate insulation), and 7 (if your insulation is not so good).
So if you have a 1200sq ft. house with 8' ceilings then you have 9600 cu ft and we will say you have moderate insulation so multiply by 5 gives you 48000 BTU output so a 60000BTU input furnace will be enough.

Cooling we figure much easier rule of thumb. 600 sq ft = 1 ton so above said home would use a 2 ton a/c.

Hope this helps.

Answer 5

Square footage, or cubic footage

Square footage = length X width
Cubic footage = Length X Width X Height

Answer 6

The measurement you are looking for is the volume of the house in cubic feet (length X width X heighth) in feet. Use the width of the floor times the length of the floor times the heighth of the building. This will give you the volume of a rectangle. Since your house is basically a triangle, divide the total by one half.

Answer 7

Multiply the over all length by the width for sq. ft. ignore the interior walls. If two story home multiply first answer by two your answer will fall in one of the various ranges. Ignoring interior walls gives positive fudge factor

Answer 8

length by width duh!