Undersized HVAC System

Old 03-23-13, 04:12 PM
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Undersized HVAC System

My son recently purchased his first house. The heating/cooling system is a split system, Carrier 13 SEER that is 3 yrs old.

We live in SC and the winters here are pretty mild.

The first night that it dropped into the 30s he noticed the next morning that the house was very cold. He had the system set on 68 degrees and the thermostat showed the house was at 59degrees and of course the system was running. It wasn't until the outside temp warmed up to the 50s did the system finally catch up to what his setting was and then finally shut off.

We called Carrier and a technician came out and checked the system completely. He said nothing was wrong with it except -- that it was undersized.

Thinking he might've just been trying to make a sale we called another Carrier technician from a different company and we got the exact same diagnosis: undersized for this house and needed replacing with a larger unit.

Then I decided to call Trane out just to see what they said. Guess what: same answer -- undersized.

My question here isn't to debate whether these 3 guys are wrong (I do believe them). My question is this: is there anything we can do as sort of a work-around so that my son can use this system until he can afford a replacement?

-- For example: there are several rooms in the house that my son says he doesn't really need to heat/cool. If we asked Carrier to shut the air to those rooms off (cap it off, whatever it's called) would that help? I mean I'm wondering if there are fewer rooms for it to heat (and later this summer, cool) will that help the system perform better at heating if it has less to send heat to?

-- All of the rooms except the bathroom have two vents. Will having Carrier close off air to one vent so that there's only one vent pushing in air to each room help?

Also, the thermostat is in a totally different room than the return. Isn't the thermostat supposed to be in the same room as the return? Or does it matter?

I'm just tossing out ideas to see if anyone thinks either or both of these ideas is a decent work around to help him out until he can afford an upgraded unit.

Old 03-24-13, 06:19 AM
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Did any of your techs tell you the size of your heat strips and the size of the wire serving them?

You may be able to install a larger electric heat strip for auxiliary heat.
Old 03-24-13, 09:13 AM
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Do you have aux heat? If so, what type, electric or gas? Closing vents will do nothing for you. The thermostat should be in the main living space. Does your thermostat have an e-heat, or emergency heat function?
Old 03-25-13, 05:25 AM
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We need a little more info, how big is the house, model # of the equipment, gas or electric heat?

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