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View Full Version : What type of HVAC to install in N. Carolina?


BillGriz
Aug 11, 2009, 01:10 PM
We are in the process of building a new brick house in the Hickory, NC area. We will be installing two split unit HVAC systems. Temps in the heat of the summer run mid 90s and can frequently dip into the 20s during the winter nights but tend to stay in the 30s or higher. Teens and single digits a few times each winter. I'm considering heat pumps and I assume I will need a supplemental heating system. I mention the house will be brick because I've read it will tend to moderate the temp swings in the house. Not so good in the summer but (with a heat pump) may actually be beneficial in the winter.

The question is, would I get by OK using electric heat strips or would I be better off going to gas. These will be air transfer heat pumps. Electric rates are fairly reasonable and tend to be stable compared to gas (at least natural gas - price is reasonable... most of the time). I'm not that familiar with the effectiveness of heat pumps during colder weather so I'm not sure which way would be best.

Next question - would I just be better off skipping the heat pumps and going to a standard AC/gas system.

ac101
Aug 11, 2009, 01:22 PM
Hello billgriz I live a bit south of you and have similar summer weather. My winter are a little milder highs in th 50s and Lowe's in the mid to upper twenties. I have a heat pump that works well for me and unless it gets very cold saves money on energy. My electric heat engages below about 33 degrees outside. At that point its no more efficient than a standard electric furnace. Where its saves me money is during the months that it functions solely as a heat pump. Also keep in mind that mine is about 8 years old and although in good condition newer ones are most likely more efficient. Hope this helped. GOOD LUCK, AC

BillGriz
Aug 11, 2009, 06:02 PM
AC101,

Thanks for your response. I think I'll go with the heat pump and electric heat strips. It may be expensive to run the heat strips but then I won't have to mess with gas. No gas service so I'd have to have a storage tank installed. I've been tossing the different options around and the heat pump does seem like my best choice under the circumstances.
Thanks again,
Bill

dac122
Aug 14, 2009, 10:32 AM
You are in the ideal climate for a heat pump: high need for cooling/dehumidification, and mild winters. Make sure a Manual J is done to determine the proper sized equipment. While I'm not a big fan of the higher SEER units due to their complexity, VS blowers, and needed ductwork remediation; in your case I might recommend it since the ductwork can be designed from scratch to provide the right static pressure for such as system. A higher SEER unit with two speed compressor might also minimize, or nearly eliminate, your heat strip usage, while at the same time providing a better balance between your summer heat gain, and winter heat loss.

Yes, you will need backup heat. If you post your KWH cost including taxes, and your propane cost, I can post how to calculate the operation cost comparisons.