BTU for 2 floors?

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  #1  
Old 08-22-19, 04:09 PM
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BTU for 2 floors?

We want to install one heat pump with 2 outlet units, one on each floor. The floor space of each floor is 1,000 sq ft. So, 2,000 total.
However, you could probably reduce a bit for the bathrooms on each floor that won't need cooling etc.
So, maybe 1400 total.
The AC guys are recommending only one 12,000 BTU heat pump for both floors. Is that enough?
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Everything I've seen says that isn't enough. It could be because upstairs is bedrooms not used during the day and downstairs not used at night but there's always a few hours where both would be on.
 
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Old 08-22-19, 05:36 PM
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Sizing isn’t done by square footage. You need a manual J load calculation.
 
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Old 08-23-19, 09:45 AM
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Has an inverter also. How does that balance out the load?
 
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Old 08-23-19, 09:58 AM
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Doesn’t matter. Still needs a load calculation done.
Variable speed is no excuse for oversizing.
 
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Old 08-23-19, 04:59 PM
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You seem concerned with cooling - are you heating too ? 12000 btu/hour is only a 1 ton unit - which won't do the heating job anywhere in Quebec I'd bet - unless your building is super insulated. For a rough idea, my similar size house near Boston has 3.5 ton (44000 btuh) .
 
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Old 08-24-19, 07:35 AM
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Heating as well but with baseboards to help.
is mostly for cooling.
it's a terraced townhouse so both side walls are into other houses. The back wall faces South, the front North.
Still seems like a 12,000 unit per floor is a bit light. 2 contractors recommended this though.
I'll try and find a j load calculator online
 
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Old 08-24-19, 08:00 AM
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HVAC Load Calculation - Maunualj - Whole House Loadcalc
Be very accurate. Junk numbers in=junk results out.
 
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Old 08-25-19, 02:24 PM
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Considering that Quebec-Hydro has very low-priced electricity, the heat pump virtues don't matter much … so maybe 12000 btuh for air conditioning, about the equivalent of two modest window AC units, might well be okay.
 
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Old 08-25-19, 06:23 PM
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A window unit can't cool an entire apartment though. Are the heat pump units better such that the same BTU cools more space?
 
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Old 08-25-19, 06:36 PM
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A BTU is a BTU, there’s no difference no matter what type of equipment your discussing.
And sizing isn’t important because of your electric bill or electric rates. It’s so your equipment runs properly and can condition the space like it’s supposed to.
 
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Old 08-26-19, 04:47 AM
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How are you going to cool the bedrooms if the unit isn't in them?
 
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Old 08-27-19, 03:33 PM
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Unit will be aimed directly down a hallway and all bedroom doors open to the hallway. Doors open a bit and fans on in summer.
 
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Old 08-27-19, 03:52 PM
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Why not do a minisplit with a ducted indoor unit that can serve all the bedrooms no matter of door position and not need fans?
Or a multihead mini with cassettes for each room.
 
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Old 08-28-19, 04:24 PM
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The ducted option requires either a lower ceiling or a small tunnel structure encased with drywall?
and the cassette options I presume require copper lines fed through the joists to each room?
What's the difference between having cassettes or just head units in each room?
 
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Old 08-28-19, 05:29 PM
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Cassettes do a better job in a larger room as they can broadcast the conditioned air in 4 directions at once. I also consider them easier to service.
Yes, for a ducted unit you’d need space for duct.
 
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