Buying An Energy-Efficient Air Conditioner

[jbrain]

A 9000 btu unit is 2.64 kw or 2.64 units of elec per hour.

In my experience the dealers use conversion sizing charts which are completely over-rated, sometimes by 300%.

They don't want the compressors running at a high duty cycle, as they are afraid of motor burn-out and system failure.

objection Your Honour! a 9k btu/h unit uses less than 0.9kW (units) per hour. conventional compressors (not inverters) run at a constant speed. there's no such thing like a high or low duty cycle.

I thought the power usage of an aircon unit was related to the SEER rating of the unit, so saying how much power a 9000 Btu aircon use without knowing the seer rating is just making a shot in the dark.

SEER denotes the efficiency of a unit's cooling capacity. the actual power usage in kWh is determined by the energy drawn by the compressor, the condenser fan and the evaporator fan irrespective of the SEER rating... and irrespective of "brain" people who think they can shoot like a sniper.

How to Calculate Air-Conditioning Costs (Worksheet 2)

The cost of operating a room air conditioner varies according to several factors, including the following:

• the EER and cooling capacity of the air conditioner;
  
• the temperature setting you use;
  
• whether you run the fan on "continuous" or "auto" mode;
  
• which of the unit's features you choose to use;
  
• how often you use the unit;
  
• the price of electricity; and
  
• the weather.
  

To estimate the energy cost of a specific room air conditioner before you buy it, multiply the unit's energy consumption by the price of electricity in your region. Worksheet 2 (below) will help with this calculation.

http://oee.nrcan.gc....rcond-2011/4454

http://oee.nrcan.gc....oomaircond/9682

[Naam]

Well the sniper shoots again Seems that Jombom was quite right

the sniper is a technical ignorant who shoots blanks because obviously he does not know that cooling capacity is nowadays expressed not only in ancient and anachronistic British Thermal Units per Hour (btu/h) but internationally in Kilowatt (kW).

here's a free lesson for those who don't know the difference of kW and kWh:

-2.637xxx kW is the equivalent of 9,000 btu/h

-0.9 kWh or 900 Watt (±10%) is the electric energy drawn by a modern 9,000 btu/h aircon unit.

repeat: kW = capacity, kWh = energy consumption

a aircon unit that draws 2.637xxx kWh has a cooling capacity of approximately 26,000-28,000 btu/h.

[jbrain]

Well the sniper shoots again Seems that Jombom was quite right

the sniper is a technical ignorant who shoots blanks because obviously he does not know that cooling capacity is nowadays expressed not only in ancient and anachronistic British Thermal Units per Hour (btu/h) but internationally in Kilowatt (kW).

here's a free lesson for those who don't know the difference of kW and kWh:

-2.637xxx kW is the equivalent of 9,000 btu/h

-0.9 kWh or 900 Watt (±10%) is the electric energy drawn by a modern 9,000 btu/h aircon unit.

repeat: kW = capacity, kWh = energy consumption

a aircon unit that draws 2.637xxx kWh has a cooling capacity of approximately 26,000-28,000 btu/h.

Think you're talking in circles there.

What have you told us what wasn't in my post already, and contradicts your reply to Jombom ?

[Naam]

i feel sorry for "brainy" people who possess a wealth of

no technical idea but insist on endless trolling which

confuses people who seek tangible advice in this forum.

Edited December 27, 2012 by Naam

[kaptainrob]

my 18.000 btu samsung aircon if used for 8 hours a night at around 25 dont like it to cold costs me about a 1000 bhat a month bargin

Holy crap, that's near double our total power bill!

Yes but not everybody uses kerosine lamps, cold showers and and a hand fan.

555 very funny. Our power bill was 585 bt average using a/c 8hrs per night, 4 hot showers a day with at least 2 pedestal fans running most of the day. LED TV and 2 PC's used for ~ 8hrs per day also.

[jombom]

A 9000 btu unit is 2.64 kw or 2.64 units of elec per hour.

In my experience the dealers use conversion sizing charts which are completely over-rated, sometimes by 300%.

They don't want the compressors running at a high duty cycle, as they are afraid of motor burn-out and system failure.

objection Your Honour! a 9k btu/h unit uses less than 0.9kW (units) per hour. conventional compressors (not inverters) run at a constant speed. there's no such thing like a high or low duty cycle.

Touche Naam. Mea culpa, I forgot completely about the COP --- must be getting old, but as they say ''even Homer nods'' etc etc.

I looked up the rating for 9000 btu and the power consumption is given as 743 watts.

Perhaps the reason people are getting confused about humidity, is because so-called aircon units in this country do not condition the air --- they are air coolers. The fact that they reduce the humidity is a byproduct.

[Naam]

Touche Naam. Mea culpa, I forgot completely about the COP --- must be getting old, but as they say ''even Homer nods'' etc etc.

I looked up the rating for 9000 btu and the power consumption is given as 743 watts.

Perhaps the reason people are getting confused about humidity, is because so-called aircon units in this country do not condition the air --- they are air coolers. The fact that they reduce the humidity is a byproduct.

743 watts is an excellent value. many rainy seasons ago, when i was young , a 9k btu/h unit (we continentals called it 2,250 kcal/h) used nearly double the energy. but i think we have reached now a stage where the laws of physics established a concrete wall which science won't be able to break, meaning no more those efficiency gains which we saw during the last three decades.

[Naam]

my 18.000 btu samsung aircon if used for 8 hours a night at around 25 dont like it to cold costs me about a 1000 bhat a month bargin

Holy crap, that's near double our total power bill!

Yes but not everybody uses kerosine lamps, cold showers and and a hand fan.

555 very funny. Our power bill was 585 bt average using a/c 8hrs per night, 4 hot showers a day with at least 2 pedestal fans running most of the day. LED TV and 2 PC's used for ~ 8hrs per day also.

it is either the tooth fairy or another benign being with special powers that rig your electric meter or your aircon runs on fan only and you call lukewarm water "hot".

joke aside. the claim "using an aircon 8 hours" is like telling "that piece of string was quite long"

[jbrain]

i feel sorry for "brainy" people who possess a wealth of

no technical idea but insist on endless trolling which

confuses people who seek tangible advice in this forum.

Ok, we all know from this post of yours that you know EVERYTHING about electrical power.

http://www.thaivisa.com/forum/topic/517870-ups-battery-question/#entry4910572

Or not ?

But, you are correct that I confused power consumption with cooling capacity, however the fact that you keep insisting that a 9000 Btu aircon uses 0.9 Kw without knowing the SEER rating, indicates that you are just parroting a figure someone blew in your ear and don't actually know how to calculate it.

Energy Input = Cooling Output / SEER

[kaptainrob]

it is either the tooth fairy or another benign being with special powers that rig your electric meter or your aircon runs on fan only and you call lukewarm water "hot".

joke aside. the claim "using an aircon 8 hours" is like telling "that piece of string was quite long"

So Mr X-Spurt how would you explain using aircon* each night, 10pm to 6am?

And shower HW heaters need only run 'lukewarm' for a comfortable shower.

*set at ~26c/low speed fan in room size 24 sq/m.

April thru July we also used an electric hob/oven, in an apartment, and monthly a/c was never more than 900Bt... usually under 800.

[Naam]

i feel sorry for "brainy" people who possess a wealth of

no technical idea but insist on endless trolling which

confuses people who seek tangible advice in this forum.

Ok, we all know from this post of yours that you know EVERYTHING about electrical power.

http://www.thaivisa....n/#entry4910572

Or not ?

But, you are correct that I confused power consumption with cooling capacity, however the fact that you keep insisting that a 9000 Btu aircon uses 0.9 Kw without knowing the SEER rating, indicates that you are just parroting a figure someone blew in your ear and don't actually know how to calculate it.

Energy Input = Cooling Output / SEER

insisting that an efficiency rating such as SEER has any bearing on the rated energy consumption of an aircon unit, respectively its energy drawing parts, proves what i claimed before, id est you possess a wealth of no technical knowledge.

isn't there anything that might help you to overcome your boredom which also stops you from ridiculing yourself? no dirty dishes to do in the kitchen? what about laundry, ironing or watering the plants?

[cooked]

We use the one air conditioner (bedroom/office) maybe three hours a day plus 20 minutes before we go to bed, then Mitsubishi floor fan (keeps the mozzies away). In the eating /TV/ kitchen area, 18 000 BTU, maximum 2 hours a day. Increase in electricity bill (mind you, this is the 'cool' season) ฿500.- a month.

I plan on getting reflective foil under the roof and an outside covered area to keep the sun of the walls. The roof area needs venting, when I touch the ceiling it is positively radiating heat downwards at present.

I found this site gave gave straight forward information about sizing: http://<URL Automatically Removed>/view.php?pg=thailand_air_conditioning

They also mention that an oversized unit will cool the room down quickly and shut off before it has done an adequate job of removing the humidity, which is what causes the discomfort.

[kaptainrob]

We use the one air conditioner (bedroom/office) maybe three hours a day plus 20 minutes before we go to bed, then Mitsubishi floor fan (keeps the mozzies away). In the eating /TV/ kitchen area, 18 000 BTU, maximum 2 hours a day. Increase in electricity bill (mind you, this is the 'cool' season) ฿500.- a month.

I plan on getting reflective foil under the roof and an outside covered area to keep the sun of the walls. The roof area needs venting, when I touch the ceiling it is positively radiating heat downwards at present.

I found this site gave gave straight forward information about sizing: http://<URL Automatically Removed>/...ir_conditioning

They also mention that an oversized unit will cool the room down quickly and shut off before it has done an adequate job of removing the humidity, which is what causes the discomfort.

A fibre-glass (batts in Nz/Oz) in foil blanket is essential. Too late for foil-only, that should be installed during roof tile install.

Whirly-bird roof cavity (ceiling) ventilators are excellent and sold throughout Th. Without ceiling insulation or cooling of some kind (more is better), an a/c unit will battle to reduce temps at your expense.

[cooked]

Thanks kaptain. I was thinking of taking the roof off, applying the foil and then attaching wooden lathes to the steel construction (through the foil) before putting the roof back. I must admit I haven't thought this through yet.

[kokesaat]

I'll leave the technical stuff to the experts.......here's my experience. We had a 24kbtu old style ac that ran pretty much 24/7 to cool a bedroom at night and a living room (albeit not well) during the day. Two years ago we trashed the old, and bought 2 daikin inverters (18k btu each) and a 6k carrier. One daikin in the big bedroom, one in the living room, and the carrier in a smaller bedroom.

Our house is easily 30% cooler than before, and our electric bills are about 30% lower. And during the rainy season, the humidity level in the 3 rooms is much lower (no nasty smells).

How it all works, I don't know, but I do know it was money well spent.

Edited December 27, 2012 by kokesaat

[kaptainrob]

Thanks kaptain. I was thinking of taking the roof off, applying the foil and then attaching wooden lathes to the steel construction (through the foil) before putting the roof back. I must admit I haven't thought this through yet.

You could do that, also. Labour's cheap in Th and foil sarking provides water-proof integrity.

Installing Batts in foil, glass wool blanket or whatever it's called, is the best way to insulate existing roof/ceiling areas.

[onthedarkside]

Inflammatory post and the response, removed.

[MaiDong]

my 18.000 btu samsung aircon if used for 8 hours a night at around 25 dont like it to cold costs me about a 1000 bhat a month bargin

Holy crap, that's near double our total power bill!

Yes but not everybody uses kerosine lamps, cold showers and and a hand fan.

555 very funny. Our power bill was 585 bt average using a/c 8hrs per night, 4 hot showers a day with at least 2 pedestal fans running most of the day. LED TV and 2 PC's used for ~ 8hrs per day also.

That is absolutely incredible!

Our electric bill is always over B3,000, I use:

1 pc on 24 hours a day.

1 aircon unit(not sure of BTU but it sort-of cools our 22sq/m bedroom for approx 8 hours a night.

6 warm showers.

1 pedestal fan on 24 hours a day and a couple of others on and off throughout the day.

8 lights throughout the house during the evening, and maybe 1 or two in the daytime.

I'm thinking of getting new aircon due to ours being ridiculously noisy(it's a Singer unit and it's crap), and not particularly cooling.

I'm thinking of Mitsubishi 'Slim' or a Daikin model, the problem with our bedroom is that the ceiling is pathetically insulated, it's just hung tiles, and as soon as the aircon is turned off the room bakes. So along with a new aircon unit I'd like to put some insulation above our ceiling tiles but I'm worried about it not being strong enough, it was put up by our landladys husband but he's an odd-job man, not a professional! Can I get a really lightweight foam?

What insulation should I look at and how much might it cost for the whole upstairs? Bedroom is 3.9m x 5.65m, 2nd bedroom/office is 2.75m x 4.35m so 34sq/m in total?

[MaiDong]

Which one of these should I buy? If any? Homepro insulation

[mcgriffith]

Moved to the Do It Yourself housing forum, with a live link remaining on Chiang Mai.

[MaiDong]

Which one of these should I buy? If any? Homepro insulation

I'm bumping this last post up because I want to go and buy my aircon today, I was thinking of asking the aircon engineers which insulation to use but I'm not sure I can trust their answer...so I'll try one more time here and if I can't get a reply then I think I'll just go with this one HOME BASE 0.6X4M EX-COOL FIB.GLASS INSULATIONPrice: ฿389.00 ฿295.00

any opinions?

[Khun Jean]

I have similar and it works ok. Thicker would be better, maybe 2 layers?

[MaiDong]

I have similar and it works ok. Thicker would be better, maybe 2 layers?

I have similar and it works ok. Thicker would be better, maybe 2 layers?

Have you noticed a change in your electricity bills?

[jbrain]

Which one of these should I buy? If any? Homepro insulation

I'm bumping this last post up because I want to go and buy my aircon today, I was thinking of asking the aircon engineers which insulation to use but I'm not sure I can trust their answer...so I'll try one more time here and if I can't get a reply then I think I'll just go with this one HOME BASE 0.6X4M EX-COOL FIB.GLASS INSULATIONPrice: ฿389.00 ฿295.00

any opinions?

Take a look at Global House if there is one in your area, they have a similar product with the same dimensions at 195 Baht.

Use 2 layers across over each other.I have it in my house and rarely use a fan during daytime, I keep windows open 24/7 however to get ventilation.

[cooked]

Don't bother asking the 'engineers' about insulation. The above advice is good, maybe overkill. I will be doing this soon, at the same time installing ventilation in the eaves of the house, am thinking about a whirligig as well, one thing at a time. The insulation should be enveloped with reflective foil.

[MaiDong]

Which one of these should I buy? If any? Homepro insulation

I'm bumping this last post up because I want to go and buy my aircon today, I was thinking of asking the aircon engineers which insulation to use but I'm not sure I can trust their answer...so I'll try one more time here and if I can't get a reply then I think I'll just go with this one HOME BASE 0.6X4M EX-COOL FIB.GLASS INSULATIONPrice: ฿389.00 ฿295.00

any opinions?

Take a look at Global House if there is one in your area, they have a similar product with the same dimensions at 195 Baht.

Use 2 layers across over each other.I have it in my house and rarely use a fan during daytime, I keep windows open 24/7 however to get ventilation.

I'm in Bangkok, I believe Global House is only in the provinces, I have checked their website and the closest branch I can find is Tumbon Lumphaya, Amphur Muang Nakhon Pathom, Nakhon Pathom 73000 which is pretty much 50km's away, as the crow flies...

Don't bother asking the 'engineers' about insulation. The above advice is good, maybe overkill. I will be doing this soon, at the same time installing ventilation in the eaves of the house, am thinking about a whirligig as well, one thing at a time. The insulation should be enveloped with reflective foil.

Yes, I don't think 2 layers is neccessary, the first bedroom I want to insulate is 21.6sq/m and that's going to cost approx. B4,000 with just a single layer of 3" 0.6 x 4m!

[MaiDong]

My bedroom is 21.6 sq/m, it's north-facing, the ceilings are 2.65m high, they are hung gypsum ceiling tiles.

Would a 12,000 BTU Mitsubishi aircon unit be adequate? I plan on using a single layer of 3" insulation and I'm also going to close up the gaps in the windows from the shoddy build of the house & the movement since the house was built.

We like to sleep in pretty frosty conditions so would that be adequate?

12,000 BTU is going to cost B21,000, an 18,000 BTU is going to cost almost B30,000.

Any advice?

[Naam]

We like to sleep in pretty frosty conditions so would that be adequate?

define "frosty".

[MaiDong]

We like to sleep in pretty frosty conditions so would that be adequate?

define "frosty".

Very, very cold, so cold that we need a nice big quilt to prevent our toes dropping off, I like to breath cold air whilst being all wrapped up cosy.

We're both very hot people, human cookers.

[MaiDong]

The shitty Singer unit we have now is mostly on 21c, and sometimes that's not cold enough