Higher BTU needed for an inverter air con

[offset]

I have been looking for a new air con but everywhere I ask I have been told that an Inverter air con unit does not cool the room as much as a normal air con unit is this true

I have a 12000 BTU inverter unit now which does not cool the room much at all and when people come to repair it they just say it is not big enough for the room but when I go to buy a new unit I am told that 12000 BTU normal air con will be ok so I am a bit confused what to do

The room size is 4mtr x 4.5mtr and 3mtr high with a big glass door facing the sun in the afternoon

Can anybody advise me what size and type of unit I should bye

[Anthony5]

12000 Btu would be sufficient for that size of room, of course a lot depends on the quality of the installed unit and the insulation of the room.

It also depends on what temperature you consider to be cool. I'm personally very comfortable with 26°, but there are others that will require 21°.

[offset]

12000 Btu would be sufficient for that size of room, of course a lot depends on the quality of the installed unit and the insulation of the room.

It also depends on what temperature you consider to be cool. I'm personally very comfortable with 26°, but there are others that will require 21°.

The unit I use now never gets the room below 26C even at night during the day at this time of year I am lucky if it cools the room to 30C

[Crossy]

Do you have curtains you can pull across that big door, it's possible the heat load from the door is overwhelming the A/C?

Filters clean?

If you set the temperature to the lowest it will go (so the unit is running flat out) the indoor unit should be pumping out very cold air, is it?

Not something silly like you having it set to 'dry' is it, 'cool' often shows as a snowflake symbol?

[Anthony5]

12000 Btu would be sufficient for that size of room, of course a lot depends on the quality of the installed unit and the insulation of the room.

It also depends on what temperature you consider to be cool. I'm personally very comfortable with 26°, but there are others that will require 21°.

The unit I use now never gets the room below 26C even at night during the day at this time of year I am lucky if it cools the room to 30C

My bedroom is 16.3m², which is about 2m² less than yours, and my 12000 Btu Daikin inverter aircon has it down to 26° in less than an hour with the fan at night setting.

Clearly something wrong with your unit, settings or room insulation. I suspect the unit.

Edit : I just double checked and our bedroom is instead 22m².

Edited December 3, 2014 by Anthony5

[lopburi3]

Does not compute - I have two bedrooms of 24 plus square meters and 9k cools them fine 24 hours a day. But I normally like 27 and children 25 (inverter model in children room). The inverter is very fast to cool and they have higher capacity than stated for short periods so do not believe a larger unit is required. But as said that doorway could be key - get foil backed curtains for it - and have the air conditioner serviced if not done within last year. Make very sure you keep the dust filters in the inside unit clean.

[offset]

Do you have curtains you can pull across that big door, it's possible the heat load from the door is overwhelming the A/C?

Filters clean?

If you set the temperature to the lowest it will go (so the unit is running flat out) the indoor unit should be pumping out very cold air, is it?

Not something silly like you having it set to 'dry' is it, 'cool' often shows as a snowflake symbol?

Curtains are always closed

Even at night time the unit never drops the temperature to below 27C I have 2 of the same units I different rooms and both seem as bad as each other

I have had many different people come and service the units but when they leave it is still the same

I have set the units on the snowflake sign

When I turn on the unit it only ever seems to drop the temperature by 3C and then follows the temperature outside up or down

I have double thermal blocks in the walls and have insulated the ceiling

Other than replacing the units I not know what else I can do

[lopburi3]

You are getting cold air when you start? Make sure the temperature sensor probe is not making contact with fan coil (they might miss that on service). Are you sure about the room being 4x4.5 meters? That is a very small room.- smaller than most hotel rooms. You have confirmed units are actually rated 12k BTU (make/model might help troubleshoot).

[lopburi3]

Is your outside unit in direct sun? Is there good airflow through that unit (not too close to wall or ceiling)?

[offset]

You are getting cold air when you start? Make sure the temperature sensor probe is not making contact with fan coil (they might miss that on service). Are you sure about the room being 4x4.5 meters? That is a very small room.- smaller than most hotel rooms. You have confirmed units are actually rated 12k BTU (make/model might help troubleshoot).

Yes it is a smaller room than most hotel rooms

It is a Mitsubishi MSZ-SGE13VA

[Anthony5]

You are getting cold air when you start? Make sure the temperature sensor probe is not making contact with fan coil (they might miss that on service). Are you sure about the room being 4x4.5 meters? That is a very small room.- smaller than most hotel rooms. You have confirmed units are actually rated 12k BTU (make/model might help troubleshoot).

Yes it is a smaller room than most hotel rooms

It is a Mitsubishi MSZ-SGE13VA

With that particular aircon and the room specifications you note, there clearly must be something wrong if it doesn't get the room cooled to 20° and below.

[IMHO]

No, inverter AC's do not need to be higher BTU's. Whoever told you that doesn't understand what a BTU is, LOL.

That said, do check the actual specs - some "12,000 BTU" A/C's might only be <=11.5K BTU, others might be >=12.5K BTU - i.e. They are loosely rounded to the nearest normal size (9, 12, 18, 25) when being discussed.

As for you own issues, that's a challenging one. 12K BTU should be enough for your space. What brand/model are the units you have? How hot does the room get without AC on?

Edited December 3, 2014 by IMHO

[offset]

No, inverter AC's do not need to be higher BTU's. Whoever told you that doesn't understand what a BTU is, LOL.

That said, do check the actual specs - some "12,000 BTU" A/C's might only be <=11.5K BTU, others might be >=12.5K BTU - i.e. They are loosely rounded to the nearest normal size (9, 12, 18, 25) when being discussed.

As for you own issues, that's a challenging one. 12K BTU should be enough for your space. What brand/model are the units you have? How hot does the room get without AC on?

Room get up to 36C in the afternoon but at night time about 30C but even at night time the room never gets below 27C

[offset]

Is your outside unit in direct sun? Is there good airflow through that unit (not too close to wall or ceiling)?

Yes it is in direct sunlight and I thought that might be the problem but the air con unit still does not reduce the temperature even at night

Yes there is good air flow round the unit

[robblok]

Does not compute - I have two bedrooms of 24 plus square meters and 9k cools them fine 24 hours a day. But I normally like 27 and children 25 (inverter model in children room). The inverter is very fast to cool and they have higher capacity than stated for short periods so do not believe a larger unit is required. But as said that doorway could be key - get foil backed curtains for it - and have the air conditioner serviced if not done within last year. Make very sure you keep the dust filters in the inside unit clean.

I have a Mishubishi inverter too 15.000+ btu and it cools slow too. The original installer says its normal that it cools slow. So after getting bored with them I called Mishubishi and they came.. cleaned it changed some things its cooler but even they say that inverter aircons cool slower (this was today)

[Anthony5]

Does not compute - I have two bedrooms of 24 plus square meters and 9k cools them fine 24 hours a day. But I normally like 27 and children 25 (inverter model in children room). The inverter is very fast to cool and they have higher capacity than stated for short periods so do not believe a larger unit is required. But as said that doorway could be key - get foil backed curtains for it - and have the air conditioner serviced if not done within last year. Make very sure you keep the dust filters in the inside unit clean.

I have a Mishubishi inverter too 15.000+ btu and it cools slow too. The original installer says its normal that it cools slow. So after getting bored with them I called Mishubishi and they came.. cleaned it changed some things its cooler but even they say that inverter aircons cool slower (this was today)

Maybe they didn't know what they were talking about, as usual.

http://www.airconditioner.me.uk/Benefits_of_Inverter_Air_Conditioning.html

How does Inverter Air Conditioning work?

The amount of cooling or heating required by an air conditioning unit varies depending on the outdoor temperature and the amount of heat in the room.

When the cooling or heating capacity needs to be increased,the compressor will operate at a high speed and will increase the amount of refrigerant flow.

Conversely, during moderate outside temperatures for example, when the cooling and heating capacity needs to be decreased,the compressor will operate at a low speed and will decrease the amount of refrigerant flow.

When the inverter air conditioning is switched on, the compressor operates at a high speed in order to cool or heat the room quickly. As the room temperature approaches the set temperature, the compressor slows down, maintaining a constant temperature and saving energy. Any sudden fluctuation in the room temperature, will be sensed and instantly adjusted to bring the room temperature back to the set temperature. EcoAir inverter air conditioning use between 30-50% less electricity to operate.

[offset]

Does not compute - I have two bedrooms of 24 plus square meters and 9k cools them fine 24 hours a day. But I normally like 27 and children 25 (inverter model in children room). The inverter is very fast to cool and they have higher capacity than stated for short periods so do not believe a larger unit is required. But as said that doorway could be key - get foil backed curtains for it - and have the air conditioner serviced if not done within last year. Make very sure you keep the dust filters in the inside unit clean.

I have a Mishubishi inverter too 15.000+ btu and it cools slow too. The original installer says its normal that it cools slow. So after getting bored with them I called Mishubishi and they came.. cleaned it changed some things its cooler but even they say that inverter aircons cool slower (this was today)

I guess that you are having the same types of problem that I am having

Sounds like it beat not to but another Mitsubishi

Can I ask what size your room is and what type of temperatures you go down to

[robblok]

Does not compute - I have two bedrooms of 24 plus square meters and 9k cools them fine 24 hours a day. But I normally like 27 and children 25 (inverter model in children room). The inverter is very fast to cool and they have higher capacity than stated for short periods so do not believe a larger unit is required. But as said that doorway could be key - get foil backed curtains for it - and have the air conditioner serviced if not done within last year. Make very sure you keep the dust filters in the inside unit clean.

I have a Mishubishi inverter too 15.000+ btu and it cools slow too. The original installer says its normal that it cools slow. So after getting bored with them I called Mishubishi and they came.. cleaned it changed some things its cooler but even they say that inverter aircons cool slower (this was today)

I guess that you are having the same types of problem that I am having

Sounds like it beat not to but another Mitsubishi

Can I ask what size your room is and what type of temperatures you go down to

It is not a problem to get the room cool, it just takes a longer time as with my other lesser btu cheaper older samsung aircon. It was a big disappointment to be honest. It has 3000 BTU more but cools slower.

The room is max 16 m2

[robblok]

Does not compute - I have two bedrooms of 24 plus square meters and 9k cools them fine 24 hours a day. But I normally like 27 and children 25 (inverter model in children room). The inverter is very fast to cool and they have higher capacity than stated for short periods so do not believe a larger unit is required. But as said that doorway could be key - get foil backed curtains for it - and have the air conditioner serviced if not done within last year. Make very sure you keep the dust filters in the inside unit clean.

I have a Mishubishi inverter too 15.000+ btu and it cools slow too. The original installer says its normal that it cools slow. So after getting bored with them I called Mishubishi and they came.. cleaned it changed some things its cooler but even they say that inverter aircons cool slower (this was today)

Maybe they didn't know what they were talking about, as usual.

http://www.airconditioner.me.uk/Benefits_of_Inverter_Air_Conditioning.html

How does Inverter Air Conditioning work?

The amount of cooling or heating required by an air conditioning unit varies depending on the outdoor temperature and the amount of heat in the room.

When the cooling or heating capacity needs to be increased,the compressor will operate at a high speed and will increase the amount of refrigerant flow.

Conversely, during moderate outside temperatures for example, when the cooling and heating capacity needs to be decreased,the compressor will operate at a low speed and will decrease the amount of refrigerant flow.

When the inverter air conditioning is switched on, the compressor operates at a high speed in order to cool or heat the room quickly. As the room temperature approaches the set temperature, the compressor slows down, maintaining a constant temperature and saving energy. Any sudden fluctuation in the room temperature, will be sensed and instantly adjusted to bring the room temperature back to the set temperature. EcoAir inverter air conditioning use between 30-50% less electricity to operate.

Maybe they don't but i get the same information from 3 different aircon installers one of them original mishubishi service people that just went to our house today to inspect the unit. They totally took it apart and cleaned it later on too. Topped the gas up checked the electronics checked for heat ect ect. This was not the standard cleaning or anything this was an in depth inspection.

But the info you found is what i found too, but one should think that people in the business know what they talk about.

[offset]

Does not compute - I have two bedrooms of 24 plus square meters and 9k cools them fine 24 hours a day. But I normally like 27 and children 25 (inverter model in children room). The inverter is very fast to cool and they have higher capacity than stated for short periods so do not believe a larger unit is required. But as said that doorway could be key - get foil backed curtains for it - and have the air conditioner serviced if not done within last year. Make very sure you keep the dust filters in the inside unit clean.

I have a Mishubishi inverter too 15.000+ btu and it cools slow too. The original installer says its normal that it cools slow. So after getting bored with them I called Mishubishi and they came.. cleaned it changed some things its cooler but even they say that inverter aircons cool slower (this was today)

I guess that you are having the same types of problem that I am having

Sounds like it beat not to but another Mitsubishi

Can I ask what size your room is and what type of temperatures you go down to

It is not a problem to get the room cool, it just takes a longer time as with my other lesser btu cheaper older samsung aircon. It was a big disappointment to be honest. It has 3000 BTU more but cools slower.

The room is max 16 m2

So you room is smaller than my room and you have a bigger BTU and you say you not happy with it think I will not buy another Inverter

ECOAIR state that an inverter should cool a room quicker than a normal unit

[Anthony5]

Does not compute - I have two bedrooms of 24 plus square meters and 9k cools them fine 24 hours a day. But I normally like 27 and children 25 (inverter model in children room). The inverter is very fast to cool and they have higher capacity than stated for short periods so do not believe a larger unit is required. But as said that doorway could be key - get foil backed curtains for it - and have the air conditioner serviced if not done within last year. Make very sure you keep the dust filters in the inside unit clean.

I have a Mishubishi inverter too 15.000+ btu and it cools slow too. The original installer says its normal that it cools slow. So after getting bored with them I called Mishubishi and they came.. cleaned it changed some things its cooler but even they say that inverter aircons cool slower (this was today)

Maybe they didn't know what they were talking about, as usual.

http://www.airconditioner.me.uk/Benefits_of_Inverter_Air_Conditioning.html

How does Inverter Air Conditioning work?

The amount of cooling or heating required by an air conditioning unit varies depending on the outdoor temperature and the amount of heat in the room.

When the cooling or heating capacity needs to be increased,the compressor will operate at a high speed and will increase the amount of refrigerant flow.

Conversely, during moderate outside temperatures for example, when the cooling and heating capacity needs to be decreased,the compressor will operate at a low speed and will decrease the amount of refrigerant flow.

When the inverter air conditioning is switched on, the compressor operates at a high speed in order to cool or heat the room quickly. As the room temperature approaches the set temperature, the compressor slows down, maintaining a constant temperature and saving energy. Any sudden fluctuation in the room temperature, will be sensed and instantly adjusted to bring the room temperature back to the set temperature. EcoAir inverter air conditioning use between 30-50% less electricity to operate.

Maybe they don't but i get the same information from 3 different aircon installers one of them original mishubishi service people that just went to our house today to inspect the unit. They totally took it apart and cleaned it later on too. Topped the gas up checked the electronics checked for heat ect ect. This was not the standard cleaning or anything this was an in depth inspection.

But the info you found is what i found too, but one should think that people in the business know what they talk about.

Rob, the sole fact that you got the same info as I posted, make it clear already that it should be the correct one. I think you have also read my post higher up as to how my inverter aircon behaves.

The only thing people in the business in Thailand know is how to avoid responsibility for warranties.

I had an almost similar issue with one of my Daikins at some point in the past, and they also claimed it to be very normal. What they forgot to take into account was that I had identical aircons in other rooms to proof they were wrong.

When I pursued the matter a bit further they were more than happy to replace the units for free, out of warranty, and the problem was solved since.

Oh by the way, Daikin management in Thailand admits that Mitsubishi is superior to their own brand.

Edited December 3, 2014 by Anthony5

[robblok]

I have a Mishubishi inverter too 15.000+ btu and it cools slow too. The original installer says its normal that it cools slow. So after getting bored with them I called Mishubishi and they came.. cleaned it changed some things its cooler but even they say that inverter aircons cool slower (this was today)

serviced if not done within last year. Make very sure you keep the dust filters in the inside unit clean.

Maybe they didn't know what they were talking about, as usual.

http://www.airconditioner.me.uk/Benefits_of_Inverter_Air_Conditioning.html

How does Inverter Air Conditioning work?

The amount of cooling or heating required by an air conditioning unit varies depending on the outdoor temperature and the amount of heat in the room.

When the cooling or heating capacity needs to be increased,the compressor will operate at a high speed and will increase the amount of refrigerant flow.

Conversely, during moderate outside temperatures for example, when the cooling and heating capacity needs to be decreased,the compressor will operate at a low speed and will decrease the amount of refrigerant flow.

When the inverter air conditioning is switched on, the compressor operates at a high speed in order to cool or heat the room quickly. As the room temperature approaches the set temperature, the compressor slows down, maintaining a constant temperature and saving energy. Any sudden fluctuation in the room temperature, will be sensed and instantly adjusted to bring the room temperature back to the set temperature. EcoAir inverter air conditioning use between 30-50% less electricity to operate.

Maybe they don't but i get the same information from 3 different aircon installers one of them original mishubishi service people that just went to our house today to inspect the unit. They totally took it apart and cleaned it later on too. Topped the gas up checked the electronics checked for heat ect ect. This was not the standard cleaning or anything this was an in depth inspection.

But the info you found is what i found too, but one should think that people in the business know what they talk about.

Rob, the sole fact that you got the same info as I posted, make it clear already that it should be the correct one. I think you have also read my post higher up as to how my inverter aircon behaves.

The only thing people in the business in Thailand know is how to avoid responsibility for warranties.

I had an almost similar issue with one of my Daikins at some point in the past, and they also claimed it to be very normal. What they forgot to take into account was that I had identical aircons in other rooms to proof they were wrong.

When I pursued the matter a bit further they were more than happy to replace the units for free, out of warranty, and the problem was solved since.

Oh by the way, Daikin management in Thailand admits that Mitsubishi is superior to their own brand.

I was not even asking for warantee just a fix at my own cost if need be. They said nothing wrong with it. But i got your info too. Anyway will have to see how the machine behaves now after what the guys did today.

I did not say I was not happy with the machine.. just that it took quite a while to cool the room, but it always cools it.

[offset]

[Oh by the way, Daikin management in Thailand admits that Mitsubishi is superior to their own brand.

[/quote

WOW if Daikin are saying that then Daikin must be bad going by the 2 Mitsubishi units I have here that can only reduce the temperature by 3C

Edited December 3, 2014 by offset

[Anthony5]

[Oh by the way, Daikin management in Thailand admits that Mitsubishi is superior to their own brand.

[/quote

WOW if Daikin are saying that then Daikin must be bad going by the 2 Mitsubishi units I have here that can only reduce the temperature by 3C

Daikin never said that their units are bad, and it should be clear from my post above that I'm quite happy with them, they said that Mitsubishi is the number one in Thailand and Daikin close second.

[IMHO]

A 12K BTU inverter has the exact same max. cooling power as a 12K BTU cyclic unit.

The only difference is, when max. power isn't needed, an inverter can vary it's power from about 50%, to 100%. A cyclic AC can only switch between 0% and 100%.

There is no difference in the ability to cool a room.

The difference is, when 100% cooling power isn't needed, an inverter will keep the temperature more stable, will run quieter, and will use less electricity.

Simple as that. Any advice you receive to the contrary is wrong.

There are however crap AC's and good ones

Edited December 3, 2014 by IMHO

[casualbiker]

Op. How old are the units. Is it still possible to get a engineer to come out direct from Mitsubishi?

[zlodnick]

I just bought an air conditioner and im curious, just what is done when a unit is (serviced?).

[Naam]

Does not compute - I have two bedrooms of 24 plus square meters and 9k cools them fine 24 hours a day. But I normally like 27 and children 25 (inverter model in children room). The inverter is very fast to cool and they have higher capacity than stated for short periods so do not believe a larger unit is required. But as said that doorway could be key - get foil backed curtains for it - and have the air conditioner serviced if not done within last year. Make very sure you keep the dust filters in the inside unit clean.

I have a Mishubishi inverter too 15.000+ btu and it cools slow too. The original installer says its normal that it cools slow. So after getting bored with them I called Mishubishi and they came.. cleaned it changed some things its cooler but even they say that inverter aircons cool slower (this was today)

I guess that you are having the same types of problem that I am having

Sounds like it beat not to but another Mitsubishi

Can I ask what size your room is and what type of temperatures you go down to

It is not a problem to get the room cool, it just takes a longer time as with my other lesser btu cheaper older samsung aircon. It was a big disappointment to be honest. It has 3000 BTU more but cools slower.

The room is max 16 m2So you room is smaller than my room and you have a bigger BTU and you say you not happy with it think I will not buy another Inverter

ECOAIR state that an inverter should cool a room quicker than a normal unit

ECOAIR states rubbish!

[Anthony5]

ECOAIR state that an inverter should cool a room quicker than a normal unit

ECOAIR states rubbish!

So how about Mitsubishi, Toshiba, Daikin, Panasonic and all the other aircon manufacturers, they also all state rubbish?

It must feel great to know everything better than any aircon manufacturer in the world.

http://www.mitsubishielectric.com/bu/air/technologies/inverter.html

Quick & Powerful Increasing the compressor motor speed by controlling the operation frequency ensures powerful output at start-up, brings the room temperature to the Comfort Zone faster than units not equipped with an inverter. Hot rooms are cooled, and cold rooms are heated faster and more efficiently.

http://www.acsisair.com.au/other-brands/panasonic/

Precise power control

The Panasonic air conditioners have intelligent Inverter feature that means the rooms are cooled and heated at a faster rate than non-inverter air conditioners.

http://eenergy.co.nz/pages/learn-about-inverter-technology-toshiba#.VH_JSMlYZrU

Toshiba, Inventor of the Inverter

In 1980, Toshiba invented the inverter - a technology now employed by most leading brands of air conditioners. Basically, what an inverter does is to cool or warm a room to the desired temperature as quickly as possible and then efficiently maintain this temperature.

http://whirlpool.net.au/wiki/aircon_faq

Inverters

The difference between inverter and non inverter is the inverter units can alter their speed in response to cooling demand. Some units have an initial over-speed period where they will run at a slightly higher capacity for a set time to pull down the temperature of a hot room

http://www.daikin.co.uk/about-daikin/leading-technologies/inverter-technology/

The inverter reduces system start-up time, so the required room temperature is reached more quickly.

[offset]

Thank you all for your help but I am know total confused what to buy now

It seems like all the manufactures state that the Inverter should cool the room quicker but in my experience and the experience of another on here finds it not to be the case and I cannot remember anybody with an inverter stating that they are working good at cooling the room quickly