Air Con Query: Estimating Btus Based On Room Size?

[bucklt]

I want to fit an air-con unit into a room 35 sqm.

What BTU rating should I be looking at?

Have looked at various websites but get conflicting results. Ideally: am looking for a 'rough formulae' which could be applied to rooms c25-100 sqm.

Would appreciate answers from those familiar with this scenario.

Bucklt

[HullyGully]

24btu or 32btu

But one with an inverter

[HullyGully]

Check out the internet, there are lots of room claculators available ...free

[WinnieTheKhwai]

Like this one: http://www.goodhousekeeping.com/home/air-conditioner-calculator

(And then fill in 'no insulation' and 'very sunny' )

[moe666]

How many windows, doors,construction materials of wall, how thick are the walls, and cielinglots of things to consider

[bucklt]

Like this one: http://www.goodhousekeeping.com/home/air-conditioner-calculator

(And then fill in 'no insulation' and 'very sunny' )

Superb response - many thanks.

(looks like c15000 BTUs for 40 sqm)

p.s websites I already looked at never mentioned insulation or Sun.

Tony

[Naam]

Like this one: http://www.goodhousekeeping.com/home/air-conditioner-calculator

(And then fill in 'no insulation' and 'very sunny' )

Superb response - many thanks.

(looks like c15000 BTUs for 40 sqm)

p.s websites I already looked at never mentioned insulation or Sun.

Tony

with 15k btu/h you can tease but not cool a 40m² room.

[Naam]

Like this one: http://www.goodhousekeeping.com/home/air-conditioner-calculator

(And then fill in 'no insulation' and 'very sunny' )

and "hot lady present".

[bucklt]

Like this one: http://www.goodhousekeeping.com/home/air-conditioner-calculator

(And then fill in 'no insulation' and 'very sunny' )

Superb response - many thanks.

(looks like c15000 BTUs for 40 sqm)

p.s websites I already looked at never mentioned insulation or Sun.

Tony

with 15k btu/h you can tease but not cool a 40m² room.

OK...so, what is the true figure then?

15k BTUs + 10%...20%...50% .....anybody???

Hence why I am having a problem here...so many different interpretations!

Tony

[circusman]

Stores like Home Pro have a chart for you right next to the a/c units.

[Naam]

so many different interpretations!

because besides 35m² which suddenly morphed to 40m² you don't submit any details.

even your opening post "I want to fit an air-con unit into a room 35 sqm" is open to

various interpretations.

please tell us why you want to fit an aircon. is it because

-you like to have a technical item in the room?

-you want to impress visitors with the aircon?

-you need a landing pad for your pet bird?

or

-do you want to cool that room?

if the latter is the case you should reveal details of the room e.g.

-living room?

-bed room?

-dog kennel?

-how many occupants?

-sun radiation on walls and windows?

-last floor of the building?

and last not least what inside temperature in ºC you want to achieve when it's outside 35ºC?

+34ºC?

+32ºC?

+30ºC?

+28ºC?

+26ºC?

+24ºC?

±0ºC?

-18ºC?

[wayned]

I use 700 btu/square meter and then pick the next available size over the calculation.

[Naam]

I use 700 btu/square meter and then pick the next available size over the calculation.

fair enough!

[Nomad97]

so many different interpretations!

because besides 35m² which suddenly morphed to 40m² you don't submit any details.

even your opening post "I want to fit an air-con unit into a room 35 sqm" is open to

various interpretations.

please tell us why you want to fit an aircon. is it because

-you like to have a technical item in the room?

-you want to impress visitors with the aircon?

-you need a landing pad for your pet bird?

or

-do you want to cool that room?

if the latter is the case you should reveal details of the room e.g.

-living room?

-bed room?

-dog kennel?

-how many occupants?

-sun radiation on walls and windows?

-last floor of the building?

and last not least what inside temperature in ºC you want to achieve when it's outside 35ºC?

+34ºC?

+32ºC?

+30ºC?

+28ºC?

+26ºC?

+24ºC?

±0ºC?

-18ºC?

Thanks Naam, you tickled my sense of humour this morning. All your comments are, of course, very relevant.

[Thighlander]

we use 1 ton for every 400 sf here in Arizona. It was 118f two years ago. 1 ton=12,000 btu. Too big will shortcycly, not dehumidify correctly, and suck electric. 14 seer is plenty.

[Naam]

we use 1 ton for every 400 sf here in Arizona. It was 118f two years ago. 1 ton=12,000 btu. Too big will shortcycly, not dehumidify correctly, and suck electric. 14 seer is plenty.

central airconditioning, as installed in the U.S., is (based on my experience) much more efficient than the single units used in Thailand.

my Florida home (very high humidity) required 8 tons (96,000btu/h) to cool it to 25.5ºC/78ºF at an ambient temperature of 35ºC/95ºF whereas in Thailand my nearly identical home needs approximately 55% more cooling capacity to achieve the same inside temperature.

[snarky66]

Been covered many times in the D.I.Y. property forum.

Personally I would want one 30,000 or 2 x 18,000 btu.

[Thighlander]

Compressors are basically made in China, in both cases. Mini-splits are stating to catch on here. http://www.georgebrazilservice.com/mini-splits/

They're pushing Mitsubishi. I've been in hot climates for 20 years, and never had an electric bill over 140 usd. Including Bullhead City...it hit 127F a few years ago. I had a 30000 btu carrier for a 700 sf condo. 8 ton would be commercial, and if yo have a large house, you would want 2 units.

[farang000999]

Why don't they use Central Air Conditioning in Thailand?

[Naam]

Compressors are basically made in China, in both cases. Mini-splits are stating to catch on here. http://www.georgebrazilservice.com/mini-splits/

They're pushing Mitsubishi. I've been in hot climates for 20 years, and never had an electric bill over 140 usd. Including Bullhead City...it hit 127F a few years ago. I had a 30000 btu carrier for a 700 sf condo. 8 ton would be commercial, and if yo have a large house, you would want 2 units.

my house was zoned. i had three units, 3+3+2 tons. this is by the way the second time i hear "commercial' in context with my home, its airconditioning and power supply. our present home in Thailand has a total installed cooling capacity of 252,000 btu/h (21 tons). home is occupied by 2 persons and 2 dogs. all private, nothing commercial

note: lowest achievable inside temperature tested three days (aug 2-4, 2006) = ~22ºC at max/min ambient temp 33/28ºC.

[Naam]

Why don't they use Central Air Conditioning in Thailand?

commercially central airconditioning is mainly used by means of chillers, cooling towers, etc. = for privat homes not practicable. it is also extremely difficult to find a contractor for a central setup. another hurdle is that big compressor/condenser units come only in 3-phase. a "no no" because it happens quite often that one of the supply phases to the home conks off completely or has a brownout (low voltage). no 3 phases = aircon system not working.

off course there are ways to design a system that gets around these limitations. the problem is to find a contractor who builds a tailormade system, and the client shelling out $$$, that works under the afore-mentioned conditions.

[Naam]

Been covered many times in the D.I.Y. property forum.

Personally I would want one 30,000 or 2 x 18,000 btu.

and the winner is... Snarky!

[HullyGully]

Thats what I would be looking at 24 / 32 BTU units

[BB1955]

Like this one: http://www.goodhousekeeping.com/home/air-conditioner-calculator

(And then fill in 'no insulation' and 'very sunny' )

Superb response - many thanks.

(looks like c15000 BTUs for 40 sqm)

p.s websites I already looked at never mentioned insulation or Sun.

Tony

I would check more I just installed a Mitsubichi inverted 18000 btus for 24 sq meter ... I personally think 15000 in this room would not have cooled it to my liking ........

[Thighlander]

I installed a pair of turbines on my roof, to suck the hot air out of the attic. Made a huge difference. Used a thermostatically controlled electric fan in my last house. Attic temp peaked at 142F. Without the fan it could have been 170F.

[Naam]

Thats what I would be looking at 24 / 32 BTU units

it all depends what temperature you would like to achieve. some people are happy with 27-28ºC, others want icicles to form on their balls.

[willienhilly]

i used to sell aircons for an electrical retailer in australia.

the formula we used (and our summer temperatures peaked around 45 deg celcius) was;

length (m) x width (m) x constant = cooling capacity in Watts

constant = 140/150 depending on insulation (all other factors were too small to worry about)

therefore: a room 4m x 5m x 150 (no insulation) = 3000 watts (3kW) required cooling capacity

[Thighlander]

For those getting units that are to large for your space, due to poor insulation, you will find condensation on your windows.