Replacing Heat Pump System

Old 05-24-07, 07:31 PM
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Replacing Heat Pump System

In all my online searching, this forum was linked to the most, so here goes my questions... Hope y'all can offer some advice.

I've gotten several quotes to replace my 20+ year old system. Carrier and Trane and Lennox. I'm not real concerned about the brand as I think they're all comparable. I felt good about 3 of the 4 companies as installers. House is about 1380 sq. ft. so all said a 2 ton system. Middle of the road in terms of models, probably 14-15 SEER, and I live in a pretty moderate NC climate. Problem is each of them had different "extras" that they recommend should be done.

Coolant line size. I want to go with 410A. Two of the four guys said my existing lines were fine and could be reconnected. The other two guys said it is standard to have larger tubing for the new coolant. Is this brand related? Who to believe?

Variable speed air handler. How important is this as an upgrade? Each of the guys talked this one up a lot, and I've done some reading that it's good, but just not sure it is necessary.

Returns. One of the companies, who seemed to be the most thorough in his measuring, said I need a new air vent return added. Said the newer, more efficient models needed more air flow. No one else said this. Is there a way to tell?

There were some other differences, such as how they would re-seal my existing ductwork, installing a new PVC drain pipe or not, and changing my radius supply, but the three things above seem to be the biggest differences in the estimates.

Any thoughts would be helpful. Thanks in advance.
Old 05-26-07, 02:15 PM
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Glad your doing homework!

600 sqft per ton (rule of thumb) eqauls 1200 sqft for 2 tons. Have a load calculation done before buying anything.

The lines should be changed or flushed, period. R-22 and R410A use different lube oils which are not compatable.

Variable speed increases efficientcy for sure but is not needed. Plus a replacement motor can cost $800 or more.

Returns, a load calc will spell out what is needed here rather than useing best guess.

PVC drain is just that, a drain pipe. It routes condensate from the unit outside the house. If it's clean no need to change it.

NC, lots of ground water, you could (while adding some cost) go geothermal and while it is extra cost for wells the electricity savings and efficientcy will pay for it in no time.



Last edited by Sharp Advice; 05-27-07 at 07:06 AM. Reason: Removed Contact Information. Not Allowed.

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