HVAC split unit questions

I think it IS possible to install a humidifier on a hot air furnace. My mid-60s furnace had one when we bought our house, but I disconnected it because I feared that it might breed bacteria.

RobertGMarvin

in Heating and Cooling 2 years and 8 months ago

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housepoor | 2 years and 8 months ago

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Some questions about A/C + heating (with hyper heat) split units as part of a (near) gut renovation: how many square feet can a typical single split unit handle? I know fine tuning this depends on solar gain, heat loss, ceiling height etc., but is there a ball park number? Is there an efficiency difference between the units that hang on the wall vs. built-in (and look like central air). How many units can a single compressor efficiently handle and can it be a mix of wall mounted and built-in/central air look alike? Thanks as always….

jimcornell55 | 2 years and 8 months ago

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How many square feet: depends on the size of the split and how many BTUs. There are formulas on line. Do you mean efficiency with a ducted vs. not ducted? Yes they can be a mix. It’s easiest to call a company like Ice Age and ask them these and other questions.

Augustiner | 2 years and 8 months ago

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I would use a 3-4 condenser units (or as you say compressor) for heating. maybe even one per floor. One reason is that these units will go into defrost mode which consumes the max amount of electricity and with one bigger unit that will inevitably push you into a ConEd commercial rate which is more expensive. Multiple smaller condensers will defrost ‘staggered’ at lower peak consumption. Another reason being that if you have a failure of one unit it doesn’t shut down the whole system but the majority of your house will be operating normally. One more reason is that if of your house is rented out you can connect the wire to the tenant panel.
Another consideration is to not oversize the units. On a brownstone floor with good windows and insulation 14k-18k btu is enough, 24k for the parlor.
Having said all that, HVAC heating sucks.

andriywww1990 | 2 years and 8 months ago

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Augustiner, thank you.

lkrshacmzcy | 2 years and 8 months ago

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Whoever you hire should do a calculation for this. They call this a Load Calculation and should be able to provide that paperwork to show what you are getting is what you need. Too many times guys throw big units in to cover their own and you end up killing your Utility.

lkrshacmzcy | 2 years and 8 months ago

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housepoor | 2 years and 8 months ago

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OP here. Thanks everyone. I want to be careful about not having too much capacity, but still getting the job done. Of course the HVAC tech will do the calculations, but I hope to be educated enough to ask good questions. The heating will be back up for an existing hot air furnace.

helen40

in Heating and Cooling 2 years and 8 months ago

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Back up? Why do you need a back up for a properly-sized and functioning hot air furnace? Why not just go with an AC unit instead of a heat pump?

RobertGMarvin

in Heating and Cooling 2 years and 8 months ago

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I wonder whether the OP meant that the hot air furnace would be the backup for the heat pump, rather than the other way around. That might make more sense.

housepoor | 2 years and 8 months ago

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OP Here: Bob is correct. The hot air furnace will be a back up for the heat pump. The furnace removes all humidity since the air gets heated to a very high temp coming out of the furnace. Putting a humidifier across it is impossible. Plus I am tired of having humidifiers in every room. I’ve been told the heat pumps are better when it comes to not completely drying out the air.

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HVAC split unit questions

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