Aircon Sizing

[HVAC 0]

I have done extensive reading online and have come up with different numbers. I am listing important things here:

1. Based on e2singapore and coolserve, we have to size it as area*65 (area is in sq. ft). Hence, a 150 sq. ft room requires 9750 BTU/hr.

2. Based on "Energy Star" from USA, a 150 sq. ft room requires only 5000 BTYU/hr. Further, I have checked other US govt. sources and they say that a 850 sq. ft home requires 3 tons (3*12000 BTU/hr). Hence, roughly a 150 sq. ft room requires 150/850*3*12000 ~~ 6500 BTU/hr in Texas, USA.

Considering that Texas is already very hot, my question is, are we oversizing our AirCons in Singapore ???

[HVAC 0]

After reading a lot, I got a 8500*2 BTU/hr for two rooms - MBR and CBR. I must say that its super cool (in Oct with little Sun due to Haze). The salesman recommended 12000 for MBR and 9000 for CBR. But I took my chances and went with a lower capacity.

My advice to people is, go for smaller capacity AirCon, unless your unit has west facing sun and you want to run the aircon in afternoon heat at 18C during peak summer in May. Else, 8500 BTU/hr for any sized room below 150sq. ft should be cool enough. Apparently, Energy Star ratings from USA that 150 sq. ft room requires only about 5000-6500 BTU/hr is a good advice.

I am running my AirCon between 23C to 26C and its perfect capacity for me I think.

[Spidy25 1]

Can share which brand and model did you choose ?

Most local contractor tend to oversize to play safe in case customer complain not cold or take too long to cool down the room.

I have a bed room of around 212sq ft, using the same calculation as you mentioned, e2sgp = 14000 BTU and USA calculation = 6000 BTU

3 contractor quote me 3 different sizing (9000BTU, 12000BTU and 18000BTU), the 1st contractor quote and the 3rd contractor quote is 9000 vs 18000 !

[qohsg001 0]

i have been reading about aircon sizing as well (for my new place in my kampong not here) and like what HVAC indicated location and heat/ sun are important factors in the BTU calculation.

I got this from one website (aircon.guru)

As every room condition is different, following scenarios should be taken into consideration to fine-tuning the sizing calculation:

• Capacity should be reduced by up to 10% should the room is well shaded.
• Capacity should be upped by 10% if the room gets a lot of the sunlight.
• Capacity should be upped by 600BTUs for each additional occupant of the room if more than 2 people inhabit the room.
• The capacity should be upped by 4,000 BTUs if the air conditioner is installed in the kitchen.
• Take into account the location of the installation of the air conditioner. If it is located in a corner of the room, the unit should be able to maneuver the air to the right way to maximize the cooling effort.
• A standard bedroom is 12 square meters (4m x 3m) and in a warm country the usual capacity for such an air conditioner unit in this room will be 9,000 BTU. The living and dining room locations will normally need a bigger capacity unit (18,000 or 24,000 BTUs)

[graciesmith 0]

Firstly, you must specify which brand you have chosen. If you have hired a good contractor then he will guide you better. When I brought my new house I have contacted hvac repair new jersey technician and he suggested me the perfect type and size of the air conditioner. As different types of air conditioners are also present like central air conditioner, ductless air conditioner, portable air conditioner, etc. So it is necessary to choose size as well as perfect type of air conditioner according to dwellings requirement.