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hennyh 01-03-2007 09:52 AM

Sizing Supplemental Strip Heaters on HP System
What are the guidelines on the proper sizing of emergency/supplemental strip heaters on a new HP/Air Handler system?

Old HP is 4T and does a decent job down to mid 30's. Old Air Handler has 20KW worth of strip heating which actually seems like overkill when they kick in.

Manual Load J confirms that 4T is the right capacity system for my home and climate.

If I assume that the strip heating (ie in emergency mode) needs to completely heat the house in the event of a HP malfunction and that 4T (48,000 BTU) is the correct capacity then that suggests that strip heating needs to be about 15KW. (ie 48,000 BTU X KW/3414 BTU = 14KW).

Does this sound like the right approach??

#CARRIERMAN 01-03-2007 10:53 AM

Hi hennyh

It looks like you have a good handle on the concept. I would go with the 15kw. This should be all that you need unless your area is subject to extreme cold for long periods. Then you would want the 20kw.

Good luck

Christopher 01-03-2007 11:28 AM


You are also limited by airflow CFM. If your HP/Air Handler is sized for a 4T coil then you are probably running about 1600 CFM max.

One of the other guys here should be able to specify the minimum CFM per 5KW strip.

If you plan on living in the house for many years and have chilly spots that insulation won't remedy, add a baseboard unit - go small - 750W.


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