What formula should I use to determine tonnage for AC

[johne]

I went shopping yesterday to (3) places for ac. I'm leery of the sales help. Only Corripo gave me a guide to use and had some understanding of the subject. I found on line a couple of guides as to how to determine. Would appreciate comments from members.
Living room. First floor of two story house.Size 20X11 (220 square feet). I'm thinking 12 K too small. Do I need 18K ?, There will be no other AC on first floor having kitchen and diining room. Overhead fan in dining room.

Comments?

 

[MariaRubia]

Depends on the ceiling height, amount of doors and the amount of windows, how much sun comes in etc. In my opinion if it's 20 x 11 and has a normal ceiling height, the room can be enclosed and hasn't got a lot of direct sun then you'd get away with a 12K. If there are complications like the room gets a lot of sun, high ceilings, lots of doors that would let the heat in, then go for the 18K.

Go for the Gree make, it's made in the same factory as Lennox but just rebadged. And go for an efficiency 20 or higher. There were some 12K efficiency 23 models around a couple of weeks ago, I think they were 38,000 pesos from memory which is much more than a normal 20 efficiency, but you would save the extra over time.

I can't remember where you're based, but if you are in the capital I have an excellent guy I can recommend who won't rook you.

 

[JD Jones]

I agree with Maria. Go a little bigger than you need, never smaller. Better to have a little bit of overkill than to have one that is overloaded.

I have a 12 in my living room (16' x 34') and it takes a while to get down to temperature. If I was buying a new one, it would be an 18.

 

[RDKNIGHT]

I went shopping yesterday to (3) places for ac. I'm leery of the sales help. Only Corripo gave me a guide to use and had some understanding of the subject. I found on line a couple of guides as to how to determine. Would appreciate comments from members.
Living room. First floor of two story house.Size 20X11 (220 square feet). I'm thinking 12 K too small. Do I need 18K ?, There will be no other AC on first floor having kitchen and diining room. Overhead fan in dining room.

Comments?

my recommendation is to always go a little bigger this way your place will cool down quicker trust me in the long run it's worth it

 

[chico bill]

Never go less than 18 for any size room. Get it cooler quicker and then let it cruise on it's DC inverter

 

[JD Jones]

BTW Johne, to answer your question, I think the industry standard formula is to multiply the sq. ft. by 20, but I think that's a little low for tropical climates.

 

[chico bill]

This website has an AC calculator. But seeing that we are in the tropic, block walls an concrete ceilings hold the heat, you should at the very least double the size needed
If your room is not on a top floor then you will likely not have as much stored heat mass to overcome or if it only has one outside wall. And if that outside wall is not exposed to afternoon sun - all the better for the room not having so much heat by bedtime.

Air Conditioner BTU Calculator

Planning to buy an air conditioner for your room? This air conditioner room size calculator will help you choose the right air conditioner size, so you will be effectively and efficiently cooling your room.

www.omnicalculator.com

 

[johne]

Y'all have confirmed in my mind to go with the 18K and high seer number. And yes I did see the formula of 20x the square footage but hesitated bc they made do mention of tropics, doors etc, so for this reason I posted here,.

Many thanks to all for as Rey would say "Good input", lol.

 

[XTraveller]

https://www.calculator.net/btu-calculator.html, Here is a good web site, but need more info about your living room?

 

[cavok]

I have a 15'x18' living room with 8' ceilings, 8' wide French doors, plus another living room window. I have a 12K btu Lennox. I could easily get the temps down into the 60's if I wanted to. 12K BTU works just fine for me.

 

[JD Jones]

https://www.calculator.net/btu-calculator.html, Here is a good web site, but need more info about your living room?

That's going in my "Conversions" bookmark folder for sure!! Thanks!

 

[cavok]

That calculator says I only need 9K BTU. No wonder my 12K BTU unit works so well!!! 18K BTU would definitely be overkill.

 

[Riva_31]

That calculator says I only need 9K BTU. No wonder my 12K BTU unit works so well!!! 18K BTU would definitely be overkill.

I have 18K AC and works very good in small roon and when I need can cool 2 rooms, also I recomend to buy Inverter AC but buy the one with the maximum energy saving in the scale. My old AC I used 4 hrs every day and my bill came always in 1,500.00 pesos and the new AC inverter Im using it 8 hrs every day and electric bill come between 1,100.00 and 1,300.00. My AC saving energy its 21 in scale of 26. Some other AC the scale its with the letter A,+ so if its that the case better buy A+++ Maximun +

 

[johne]

I have 18K AC and works very good in small roon and when I need can cool 2 rooms, also I recomend to buy Inverter AC but buy the one with the maximum energy saving in the scale. My old AC I used 4 hrs every day and my bill came always in 1,500.00 pesos and the new AC inverter Im using it 8 hrs every day and electric bill come between 1,100.00 and 1,300.00. My AC saving energy its 21 in scale of 26. Some other AC the scale its with the letter A,+ so if its that the case better buy A+++ Maximun +

Lets clarify: Are we talking about 7 days a week? Cooling in day or night"? Billing period is how many days in the cycle? You have an 18K with Eff rating of?

 

[JD Jones]

Johne, I have a 12K with an EFF of 19 that I never turn off. My bill runs around 1500 pesos a month as well.

I have it set at 79 degrees and I can feel the coolness every time I enter the room.

I also have a Hepa air Filter that keeps my filter on the A/C clear of dust.

 

[Father Guido]

approx 1 ton for every 500 sq ft

 

[Manuel01]

Stop Calculating (Sorry) there are so many aditional factors to consider and some of them were alrady mentioned;
Height of room ? What's Below ? Even More important What's Above ? How much direct Sun do you get. Windows ?
What appliances are running in the room you want to cool. Get an experienced Installer and aski him for a quote.

 

[johne]

Stop Calculating (Sorry) there are so many aditional factors to consider and some of them were alrady mentioned;
Height of room ? What's Below ? Even More important What's Above ? How much direct Sun do you get. Windows ?
What appliances are running in the room you want to cool. Get an experienced Installer and aski him for a quote.

Did that and bought unit yesterday. Will install next week and report back here in a couple of weeks.
Many thanks to all.

 

[Riva_31]

Lets clarify: Are we talking about 7 days a week? Cooling in day or night"? Billing period is how many days in the cycle? You have an 18K with Eff rating of?

Yes, I use it 7 days a week, 8 hrs at night, the eff rating of mine its 21 of 26, my billing cut the 14 of every month.