# Whole House Generator Questions



## dr electron (May 3, 2009)

There may be a thread for this already but I couldn't find my answer.
Two questions:
A customer wants to be able run the whole house, including the heat pump, on a generator. Would you recommend running the heat pump?
If so what size would you suggest. It's about a 2000 sq/ft all electric. 
I've heard it's not a good idea unless we go with about a 25KW which is about twice the cost of a 17 or 18KW.
Further, which brand would you recommend. I like the Generacs but I don't have a lot of experience with a residential application.
Thanks in advance for your help.


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## B4T (Feb 10, 2009)

A (20) KW generator would handle it using the load shedding contacts built into the ATS.. Generac..


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## McClary’s Electrical (Feb 21, 2009)

B4T said:


> A (20) KW generator would handle it using the load shedding contacts built into the ATS.. Generac..


Ummm,.if it sheds the load, he's clearly not running the heat pump.

The op has not mentioned the size of the heat pump, a calculated load on the house, or size of the emergency heat, so the question is impossible to answer.


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## JmanAllen (Aug 3, 2011)

mcclary's electrical said:


> Ummm,.if it sheds the load, he's clearly not running the heat pump.
> 
> The op has not mentioned the size of the heat pump, a calculated load on the house, or size of the emergency heat, so the question is impossible to answer.


Are guys really deciding how big of a genset the need off of Sq ft 

Like McClary said more info needed

Sent from my iPhone using ET Forum


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## Bulldog1 (Oct 21, 2011)

B4T said:


> A (20) KW generator would handle it using the load shedding contacts built into the ATS.. Generac..





KOHLER all the way
You can shed all the load you want. You still only have 83 amps.


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## drsparky (Nov 13, 2008)

Put a data logger on the service or at least turn on the likely loads and get a measurement.


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## B4T (Feb 10, 2009)

Bulldog1 said:


> You can shed all the load you want. You still only have 83 amps.



I agree.. the heat pumps I have seen for that size house were drawing (50) amps.. houses were (3) years old


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## McClary’s Electrical (Feb 21, 2009)

B4T said:


> I agree.. the heat pumps I have seen for that size house were drawing (50) amps.. houses were (3) years old


I'm wiring a house now that has 25 kw of strip heat alone


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## dr electron (May 3, 2009)

mcclary's electrical said:


> I'm wiring a house now that has 25 kw of strip heat alone


 That's a good point. Yes, the heat pump is on a 50 amp breaker but I didn't think to check the backup heat size.
Thanks, I'll check on that today.
Still would like to see more opinions on a brand. 1 vote for Generac and 1 for Kohler so far.


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## McClary’s Electrical (Feb 21, 2009)

dr electron said:


> That's a good point. Yes, the heat pump is on a 50 amp breaker but I didn't think to check the backup heat size.
> Thanks, I'll check on that today.
> Still would like to see more opinions on a brand. 1 vote for Generac and 1 for Kohler so far.


One option would be shed the strip heat through the control wiring, but still run the heat pump.


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## Bulldog1 (Oct 21, 2011)

dr electron said:


> That's a good point. Yes, the heat pump is on a 50 amp breaker but I didn't think to check the backup heat size.
> Thanks, I'll check on that today.
> Still would like to see more opinions on a brand. 1 vote for Generac and 1 for Kohler so far.



I'm a Kohler dealer if you are shopping for a genny pm me.


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## mbednarik (Oct 10, 2011)

i ran a 20 generac on a 2k house, disabled all the backup heat and garage resistance heat let it run on the geo. When the geo kicks on there is a bit of voltage drop, but it does not kick out or anything, but it might be a regulator issue though, when the geo kicks on the gas pressure drops momentarily from 12" to 8.5" for about .5 seconds. I did hear that the kohlers have a higher hp to kw so they might not have as bad of a drop, but they cost more.


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