Aircon Question

[Dave Hounddriver]

Now we all know that Google CAN'T be wrong.

 

You must be right because Google will now pick up your post and deliver it to countless minions as fact.

[Call me bubba]

  :grouphugg:

 

 

You are both right from the experiences that you have had,

[Bruce]

Now we all know that Google CAN'T be wrong.

 

You must be right because Google will now pick up your post and deliver it to countless minions as fact.

 

OK with me. And did you notice the conflict in the specs written by the orginal poster? 2 HP is certainly not 18,150 BTU. 2 HP = 24,000 BTU.

 

Based on that conflict I see issues if you have 2 customers with the same size rooms and heat loads both come into the store. 1st guy is asking for a 2 HP unit and the 2nd guy is asking for a 24,000 BTU unit.

 

Based on the original posters info, the 1st guy will leave with a 18,150 BTU unit while the 2nd guy will leave with a 24,000 BTU unit.

 

I would rather be customer #2.

[Bruce]

  :grouphugg:

 

 

You are both right from the experiences that you have had,

 Dave and I are not fighting..... I just know ac, Dave knows busses and I do not like to see people taken advantage of in the AC business. FORGET HP ratings. heat calculations today are un BTUs so ask for ac units by BTU ratings.  

 

Suppose someone said a bus gets 8 miles to the gallon (guessing) But Dave knows that after driving commercial busses, engine size and cams and transmissions mean a whole lot of variables in MPG of a 'bus'.

 

A blanket statement that a bus gets ____ per gallon is an incomplete statement without the qualifying info. Same for AC and refrigeration. Temp ranges do chgange the btu ratings and as such, alter the TON and HP ratings as all are tied together.  

[Dave Hounddriver]

I just know ac, Dave knows busse

 

Its ironic isn't it, Here's me thinking you are a gynecologist and you think I am a bus driver.  "I'm more than that! I know I am. At least, I think I must be."

[earthdome]

When it comes to high temp air conditioning.... 1 hp = 1 ton = 12000 btu. Period.

 

What you are listing here is a rule of thumb. It is an approximation based on the efficiency of the average AC unit sold today. The HP refers to how much power (energy) the AC unit can use which doesn't correlate directly with BTU since different AC units can be either more or less efficient.

 

A more accurate way to proceed is to estimate how many BTU's will be needed to cool the size and characteristics of the space. Then look for an AC unit which is 15-25% larger than that minimum capacity.

[Bruce]

I just know ac, Dave knows busse

 

Its ironic isn't it, Here's me thinking you are a gynecologist and you think I am a bus driver.  "I'm more than that! I know I am. At least, I think I must be."

 

Of course you are Dave... I thik that old whats his name said it best as .........Aristotle - "The whole is greater than the sum of its parts."

 

And I think I get extra points for not saying Ralphie Boy even once! :hystery:  I owe Sir Tom about 5 cases of beer.... so if we ever meet up in Cebu for him to collect, come and join us....

 

I am just a mechanically inclined detail oriented kind of guy..... :tiphat: 

 

[Bruce]

When it comes to high temp air conditioning.... 1 hp = 1 ton = 12000 btu. Period.

 

What you are listing here is a rule of thumb. It is an approximation based on the efficiency of the average AC unit sold today. The HP refers to how much power (energy) the AC unit can use which doesn't correlate directly with BTU since different AC units can be either more or less efficient.

 

A more accurate way to proceed is to estimate how many BTU's will be needed to cool the size and characteristics of the space. Then look for an AC unit which is 15-25% larger than that minimum capacity.

 Exactly! I have been doing IN THE FIELD AC work for over 30 years. And for at least 30 years the term HP is obsolete in the US.

 

Back when I started, it was set in stone. 12,000 btu = 1 ton = 1 HP. And since the world went energy crazy, you really can not size an AC unit by HP, as I mentioned in one of my replies.

[SubicSteve]

Bruce,

 

Thanks for all the info.  Here is the info on the outdoor unit part of my split unit aircon.   http://www.mraircon.ph/?p=1425

 

They list it at 2HP and kJ/Hr  18,150  My only reason for listing it was to show that is a 2HP motor I guess so you(or anyone else) could tell me what size thru the wall unit would be cheaper to run here in the Philippines since electricity is $$$$$$$.  Since I know I will be running the bedroom aircon every night of the year I want to get one that will cool me off but hopefully not cost me more to run than the split unit in the living room.

[Bruce]

OK the actual BTU cooling for that model is 17,200. It is ok for the main room but undrsized for the bed room too. You have a few options.

 

And you can cheat a bit if needed. Before you do anything, do you own the place? Or if you will stay there for a long time, you can save some LONG TERM money by painting the roof and outside walls white to reflect the heat before it gets in. Any way to add insulation to the ceiling space? All heat that you keep out mean that the AC does not have to remove it.

 

If your bedroom is marginal at night, you can install a quiet fan thru the wall to push air from the bed room back into the main room. So cool air enters the bed room via the door and then a pressured system is created byt pushing air back into the main room with the fan, lowering the pressure in the bed room and that lower pressure is equalized by the open door.

 

As you have it now.... cool air falls and war air rises.. convection. You are getting cooling via the cooler / heavier air simply being contained by the walls as it falls from the height of the AC. Think a takn of water and your opening the bed room door allows that tank to empty and fill the bed room space until an equal level is created. A fan increases the convection and will cool the bed room easier.

 

Single room units or thru the wall models (not the same) both do the same but are not made for energy effiency. You may see a lower bill IF you turn off them main ac at night and the (smaller) room unit is the only unit running. BUT.... remember if you turn off the main unit, the room heats up and in the morning the ac then has to work longer to reach the set temp. So depending on your habits, you may not see any savings.

 

Remember.... you are spending money.... to save money, as well as added comfort at night. How much that comfort is worth is up to you. The painting of the roof and walls will help a lot. Tight windows? A must have. If the old jalousie style, cover inside the entire window space with clear plastic and you will feel a difference.  

 

Or........ rather then spend a lot for a new window / wall ac, is it possible to spend a bit more and get a 30,000 BTU (2.5 ton) main room ac and then sell your existing one to get back some money and if needed add in the fan set up I mentioned above.

 

Are you confused yet?