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Old 05-15-2020, 03:29 PM   #1
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Heat pump size recommendation


this is for a small house 1008 sq ft. would a 2 ton will do it? also please recommend a heat strip size.

this is for north carolina.

thanks
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Old 05-15-2020, 04:06 PM   #2
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Re: Heat pump size recommendation


it's not done by sq ft, do a load calculation - https://www.loadcalc.net/

2 ton may be too big on the cooling side and not dehumidify properly, but sizing a heatpump is a balancing act.

The heat strips are sized to handle the entire heating load. Load calculation would indicate - the choice will likely be between 10 and 15kw.

it really depends on the house - being single story, having ducts in an unconditioned space,east-west exposure, large windows, poor insulation can increase the required capacity.
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Old 05-15-2020, 06:37 PM   #3
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Re: Heat pump size recommendation


X2, you need a load calculation. Equipment isn’t sized to square footage.
To add to the above post, you need to verify the duct system is capable of working well with the equipment that’s installed.
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Old 05-16-2020, 07:00 PM   #4
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Re: Heat pump size recommendation


North Carolina can get pretty humid in the summer, depending on your location. An oversized heat pump (AC) will produce a cold, clammy environment. You don't want that, so be careful to get a proper cooling load assessment. I suspect a 1.5 ton would be closer.
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Old 05-16-2020, 08:05 PM   #5
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Re: Heat pump size recommendation


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Originally Posted by form8829 View Post
this is for a small house 1008 sq ft. would a 2 ton will do it? also please recommend a heat strip size.

this is for north carolina.

thanks
This is a pretty good site for sizing HVAC systems. I've always had good luck calling local HVAC supply vendor for help also.

https://hvacdirect.com/sizing-air-co...nd-heater.html

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Old 05-16-2020, 08:26 PM   #6
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Re: Heat pump size recommendation


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Originally Posted by Kemper100 View Post
This is a pretty good site for sizing HVAC systems. I've always had good luck calling local HVAC supply vendor for help also.

https://hvacdirect.com/sizing-air-co...nd-heater.html

Thatís a terrible choice for sizing. Nothing more then an uneducated guess.
No such sizing chart exists.
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Old 05-30-2020, 07:07 PM   #7
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Re: Heat pump size recommendation


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Thatís a terrible choice for sizing. Nothing more then an uneducated guess.
No such sizing chart exists.
I disagree the internet has many tools / sites to determine the correct size for your HVAC needs. Many have online or phone tech support to discuss the variables such as duct size, insulation, wall / floor building characteristics, how many floors, climate zones, etc.

Of course IMHO and YMMV

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Old 05-30-2020, 07:25 PM   #8
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Re: Heat pump size recommendation


Heat loss/gain is not proportional to sq ft.

A 1500 sq ft house can require as much or more heat in the same climate as a 3000 sq ft one. There are too many factors for sq ft to be used.

It's more proportional to exterior/exposed surface area than floor area, but still, insulation and leakage greatly impact heat loss/gain.

There's a lot of junk on the internet along with some good stuff.
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Old 05-30-2020, 08:45 PM   #9
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Re: Heat pump size recommendation


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Originally Posted by Kemper100 View Post
I disagree the internet has many tools / sites to determine the correct size for your HVAC needs. Many have online or phone tech support to discuss the variables such as duct size, insulation, wall / floor building characteristics, how many floors, climate zones, etc.

Of course IMHO and YMMV

Unfortunately that site you linked couldnít be farther from the truth. Itís outright wrong.
Sizing isnít about someoneís opinion. Nor is it one size fits all. And no charts or graphs exist to size your home.
You need a manual J to determine sizing.
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Old 05-30-2020, 11:59 PM   #10
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Re: Heat pump size recommendation


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Unfortunately that site you linked couldnít be farther from the truth. Itís outright wrong.
Sizing isnít about someoneís opinion. Nor is it one size fits all. And no charts or graphs exist to size your home.
You need a manual J to determine sizing.
Those sites and THAT site aren't based on opinion, they're based on mechanical engineering principles of HVAC design.

Sizing residential HVAC systems not that complicated and IMO that site was perfectly fine for what the OP was asking.

Simple residential HVAC sizing isn't complicated as industrial manufacturing facilities with variable air volume vs constant air volume and humidity sensors in each room with DDC controls along with large chiller and industrial desiccant dehumidification systems with variable frequency drives and pre heating & cooling coils, that hold the system to a specific temperature and humidity design criteria for manufacturing purposes. Not to mention systems that are design around 100% outside air opposed to return air systems.

Again IMHO and obviously YMMV

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Old 05-31-2020, 12:05 AM   #11
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Re: Heat pump size recommendation


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Originally Posted by Kemper100 View Post
Those sites and THAT site aren't based on opinion, they're based on mechanical engineering principles of HVAC design.

Sizing residential HVAC systems not that complicated and IMO that site was perfectly fine for what the OP was asking.

Simple residential HVAC sizing isn't complicated as industrial manufacturing facilities with variable air volume vs constant air volume and humidity sensors in each room with DDC controls along with large chiller and industrial desiccant dehumidification systems with variable frequency drives and pre heating & cooling coils, that hold the system to a specific temperature and humidity design criteria for manufacturing purposes. Not to mention systems that are design around 100% outside air opposed to return air systems.

Again IMHO and obviously YMMV

Manual J is strictly for residential heat load calculation. Has nothing to do with industrial anything. In fact, commercial and industrial calculations have an entirely different formula.
Following the link you posted, if I had 2 identical 2500 square foot houses, located in zone 1, one with 2X4 construction with fiberglass insulation and the other spray foamed, what size equipment would I need?
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Old 05-31-2020, 12:10 AM   #12
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Re: Heat pump size recommendation


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Originally Posted by roughneck View Post
Manual J is strictly for residential heat load calculation. Has nothing to do with industrial anything. In fact, commercial and industrial calculations have an entirely different formula.
Following the link you posted, if I had 2 identical 2500 square foot houses, located in zone 1, one with 2X4 construction with fiberglass insulation and the other spray foamed, what size equipment would I need?
Again the site has online technical service to walk the user through the different variables as mentioned above.

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Old 05-31-2020, 12:20 AM   #13
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Re: Heat pump size recommendation


Again, as has already been mentioned, equipment sizing IS NOT based on square footage.
Please study the art of proper equipment sizing before offering poor, incorrect advice.

www.loadcalc.net

http://efficientcomfort.net/assets/d...ty_Control.pdf

http://efficientcomfort.net/assets/d...ent_Sizing.pdf

http://efficientcomfort.net/assets/d...s_Properly.pdf

http://efficientcomfort.net/assets/d...ign_Issues.pdf
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Old 05-31-2020, 12:33 AM   #14
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Re: Heat pump size recommendation


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Originally Posted by roughneck View Post
Again, as has already been mentioned, equipment sizing IS NOT based on square footage.
I never said equipment sizing was based on square footage. Please study the art of reading comprehension.

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Old 05-31-2020, 12:41 AM   #15
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Re: Heat pump size recommendation


Quote:
Originally Posted by Kemper100 View Post
I never said equipment sizing was based on square footage. Please study the art of reading comprehension.

The entire link you posted is based on square footage. Including the big map that gives sizing ratings based on ďzonesĒ.
This kind of graph/map doesnít exist for sizing. Links like you posted have people wind up with oversized equipment that performs poorly.
Sizing, unlike your opinion, is quite difficult and requires theory, science and mathematics to get right.
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