Aircon how many BTU needed to cool down room 3,5 x 4 x 2,4

[robblok]

Hi,

I need a new aircon for my gym and I am going to buy a Mitsubishi. I replaced all other aircons in the house by this brand and its a huge improvement.

Now I have read online that a 12000-13000 btw would do the cooling for a room 3,5 by 4 by 2,4 (350cm by 400cm by 240cm) I just want to confirm that this is correct. Because I am thinking either 18.000 or 13.000. I like to cool the room down good when I am training (say go to 20-22 degrees). It wont be used much just a few times a week.

Unless I got guests then my gymroom becomes a bedroom.

Am I right with the 13.000 btu or would people advise me to go 18.000

[TheCruncher]

12000 BTU is plenty for a room that size, if it has good insulation and hasn't the sun on the walls you could get away with 9000 BTU as well

[sipi]

Yes 3 1/2 to 4kW would be large enough. This size split system will be able to be wired/ plugged into an existing 10amp GPO without having to run extra wiring/ breakers.

[robblok]

12000 BTU is plenty for a room that size, if it has good insulation and hasn't the sun on the walls you could get away with 9000 BTU as well

Thanks for the answer I just need to room to cool down good so my exercise is done in a "relative" cool room of 22 degrees with some fans blowing too.

I was thinking 18.000 but that seems to be overkill, good to know saves me some money. the sun is actually not on it a lot its at the back of the house I get the sun at the front.

[eyecatcher]

I dont want to overkill on the same confirmations above but my quick rule of thumb is 600btu per m2 of floor plus 300btu per m2 of sun drenched external wall.

So you are at say 10/11k btu there.

Obviously always choose a higher rating 12k may be perfect or may have to work hard if those walls are warmer than you think.

[sappersrest]

Don't forget if you do a heavy or even light work out you will need plenty of fresh air as well, as you burn more oxygen you will feel hotter, in an enclosed room. Plenty of good research carried out on this .

[robblok]

Don't forget if you do a heavy or even light work out you will need plenty of fresh air as well, as you burn more oxygen you will feel hotter, in an enclosed room. Plenty of good research carried out on this .

I prefer a cool room over a ventilated room. I have been working out in the same room for many years (old aircon is just getting bad). So I am sure working out with an aircon is ok for me.

You can't have ventilation and cooling at the same time, so if I have to choose I choose cooling. There is plenty of research too on how heat affects workouts.

[questionsreplies]

22 is ridiculous. At 25 its already cool enough.

[robblok]

22 is ridiculous. At 25 its already cool enough.

Who has to train in it.. me or you ?

But in general I aim for 25 but its better to have some extra cooling capacity if needed.

Edited February 5, 2016 by robblok

[sappersrest]

Don't forget if you do a heavy or even light work out you will need plenty of fresh air as well, as you burn more oxygen you will feel hotter, in an enclosed room. Plenty of good research carried out on this .

I prefer a cool room over a ventilated room. I have been working out in the same room for many years (old aircon is just getting bad). So I am sure working out with an aircon is ok for me.

You can't have ventilation and cooling at the same time, so if I have to choose I choose cooling. There is plenty of research too on how heat affects workouts.

Please do some research on the subject before making such a statement ,a gym is completely different to living space.Fresh air is essential as well people working out in enclosed gyms get a lot hotter with just air con as opposed to systems with chilled air intake.

Fresh air is essential .

Lack of fresh air makes you feel hotter,in an enclosed enviroment .As opposed to working out in a hot environment which has benefits.

Just ask any sports scientist or HVAC engineer that has worked or designed systems for a sports hall gym etc.

Edited February 5, 2016 by sappersrest

[robblok]

Don't forget if you do a heavy or even light work out you will need plenty of fresh air as well, as you burn more oxygen you will feel hotter, in an enclosed room. Plenty of good research carried out on this .

I prefer a cool room over a ventilated room. I have been working out in the same room for many years (old aircon is just getting bad). So I am sure working out with an aircon is ok for me.

You can't have ventilation and cooling at the same time, so if I have to choose I choose cooling. There is plenty of research too on how heat affects workouts.

Please do some research on the subject before making such a statement ,a gym is completely different to living space.Fresh air is essential as well people working out in enclosed gyms get a lot hotter with just air con as opposed to systems with chilled air intake.

Fresh air is essential .

Lack of fresh air makes you feel hotter,in an enclosed enviroment .As opposed to working out in a hot environment which has benefits.

Just ask any sports scientist or HVAC engineer that has worked or designed systems for a sports hall gym etc.

I have done the research and heat negatively effects performance. Anyone knows that and there is enough scientific research to back that up. I can also from experience when my aircon was not working tell you that my training volume and weight dropped significantly.

So have fun with your engineers let them try to workout a bit themselves in a hot room.

Have you ever noticed the speed of soccer games played in cooler climates and those in warm climates ? Do you think there is a reason why in the tropics they don't do open air sports during the hottest time of the day.

Natural ventilation does not help when the outside temperature is too high.

We are talking here about a gym at home for one person.. so my room will have enough fresh air for me. I got all the equipment in there that it needs ranging from an Olympic barbell with 250kg of weights to a power-rack and some pullies and dumbbells up to 120lbs. Plus a lot of other stuff and from experience aircon is needed.

[sometimewoodworker]

In a bedroom the size you give we have a 9,000 BTU Mitsubishi MrSlim it can easily get down to 22 degrees, so if you're producing a lot of heat from your workout a 12,000 BTU unit will easily be big enough. If you go for an 18,000 unit you will not be clearing the humidity as it won't run long enough.

[Sooo Upto Me]

Why do u need a gym in ur home? U need to get out more an enjoy urself. Get fresh air visit temples an flower shows haha, instead of couped up in a sweaty box room trying to look like Arnie.

[hellstens]

I recommend you use 12-1300BTU, but use a inverter version it stays cold much smoother.

[steve73]

Depends also on where you are - i.e. external temperature.. If you're near the coast where it rarely gets much above 32-33C you should be OK with 9,000, but if you're further inland where peak temperatures can reach close to (or even above 40C) then you'll certainly require the higher rated unit.

[SOTIRIOS]

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[IAMHERE]

Remember you are not just cooling the room, you are also removing water from the air. Cool the room too quickly and you will have too much humidity in the room which will eventually make things smell 'damp' or mildewy.

[bazza40]

I would have thought the answer would depend also on whether the ceiling has insulation or not.

[Taffyfromflint]

22 is ridiculous. At 25 its already cool enough.

This is quite corret plus for every degree C below 25 the extra cost in power consumptiom is staggering. If you set the Aircon to DRY at 25 it will feel like 22 but power consuption is reduced considerably. I have a 9, 12, 18 and 30 in my house. Power consumption is reasonable considering my place faces W.

[hobobo]

22 is ridiculous. At 25 its already cool enough.

Unless he's a big fat b@$t@#d!

[Bantex]

Don't forget if you do a heavy or even light work out you will need plenty of fresh air as well, as you burn more oxygen you will feel hotter, in an enclosed room. Plenty of good research carried out on this .

I prefer a cool room over a ventilated room. I have been working out in the same room for many years (old aircon is just getting bad). So I am sure working out with an aircon is ok for me.

You can't have ventilation and cooling at the same time, so if I have to choose I choose cooling. There is plenty of research too on how heat affects workouts.

If your replacing an old air on, what was its BTU and was it sufficient when new?

[Mudcrab]

what a bunch of tossers......go for a run...if its too hot, stop and cool off,,no science involved

[robblok]

22 is ridiculous. At 25 its already cool enough.

Unless he's a big fat b@$t@#d!

Or works out like crazy.. care to see what it is ?

As for the people wondering about money, I make enough and its for an few hours a week (6 or so). Not all day long. The aircon in the bedroom is set to 25 and that is cold enough.

[robblok]

what a bunch of tossers......go for a run...if its too hot, stop and cool off,,no science involved

Running not my thing.

[robblok]

Don't forget if you do a heavy or even light work out you will need plenty of fresh air as well, as you burn more oxygen you will feel hotter, in an enclosed room. Plenty of good research carried out on this .

I prefer a cool room over a ventilated room. I have been working out in the same room for many years (old aircon is just getting bad). So I am sure working out with an aircon is ok for me.

You can't have ventilation and cooling at the same time, so if I have to choose I choose cooling. There is plenty of research too on how heat affects workouts.

If your replacing an old air on, what was its BTU and was it sufficient when new?

I had a new 9000 unit in it that was not enough.. then later i swapped that 9000 unit with an older 12.000 from an other room in my home because i bought a new one. So I have never had a new 12.000 btu in there.

[bearpolar]

i have my bedroom, almost the same size(maybe a couple CM bigger)

People told me the same stuff that is being said here

i bought a 12 000btu..

at 23 degrees its warmer than my downstair aircon(18 000btu cheap brand) in a much much larger room that i keep at 27.

The bedroom 12 000btu is of great quality(and expensive) and i just had it serviced by a very reputable farang company. I think a lot of people are older and a bit frail and don't realise that what's "cool" for them is a sweaty temperature for people in shape. Many threads you have guys tralking aobut their cheap electric bill, saying their house is cold and then they admit that they keep their 9000btu aircon at 29

get the 18000

[William C F Pierce]

A most useful topic. I will be having a house built next year and I am contemplating the use of a cavity wall with Urethane insulation. Cooler in summer, warmer in winter. So I will think I can get away with a couple of small mobile aircons. Its a pity the benefits of cavity wall insulation are not understood in Thailand.