Easy way to estimate heat pump size?

Old 06-26-06, 05:50 AM
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Easy way to estimate heat pump size?

Is there an easy way to estimate the size of a heat pump that is required for a house?

I read somewhere that the older versions were 1 ton per 400 sq ft.

I received two quotes, one for a 2 ton and the other for a 2.5 ton heat pump. Should I just go get a few more quotes and go with the consensus?
Old 06-26-06, 09:24 AM
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I dont think there is a real easy way to estimate.
There are too many variables that need to be considered.
House construction, attic insulation, windows, and window type.
Is the house ducted for forced air now?
Duct type and size can also impact the unit size.

If I went based on my current unit, it would be 1 ton for every 540 square feet.

If you place a system that is too small, it will run constantly and hardly keep up with the thermostat demand, even if it could.
Too big of a unit will not run long enough to take the humidity out of the air in the summer...and cold humid air can cause health problems.

An experianced HVAC contractor will take all of these variables into account when he calculates the unit size.
Did any of the people who quoted actually look at the windows?, did they measure the insulation depth in the attic?, did they look at the house constuction?, did they look at the existing duct system?.

It could be that they both did all of these, and the calculation came in somewhere in between a 2.0 and a 2.5 ton unit.
One rounded up...because he knows your kids like to open the widows at night, and one rounded down because he knows your house has trees all around it to shade the sun.

You should be able to go back to easch of them and ask questions based on what others have quoted.

Every contractor knows a smart homeowner will quote several different companies, and they will not be offended if you ask some questions...and if they do get offended...you dont want them working on your house.
Old 06-26-06, 02:07 PM
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When you are looking at a heatpump you also have to add in just where you live . Are we looking at more for heat are more for the AC side. We have to do that a lot here.
But like said ask them if they ran a heat loss and AC load on the home and you want to see it.
You will also get a better pay back to go to a SEER of 15 or over On this heatpump. Get 3 bids


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