Inverter Vs Standard Air Conditioners

[manchestermike]

I am about to buy a new air conditioner for my master bedroom and cant decide whether or not to purchase an inverter or standard type of system. The Inverter system is approx 8K baht more expensive.

The sales rep claims that the inverter type saves at least 20% on the electricity bill and is a quieter system .

The unit is to cool an 18m2 room using a unit rated at 15000btu. Temperature target set at 23'c. The unit will be in operation approx 12hrs/day everyday.

I have 3 panasonic aircon units in my apartment and all 3 have operated for 3 years without any problems. The only brand my friends recommend is a Daikin.

Does anybody have an easy way to calculate the cost per month ? Anybody got a panasonic or Daikin inverter system installed are they really more cost efficient / quieter ?

[lopburi3]

The label on the unit has the estimated operating cost. But I do not believe it is designed for freezer use as you seem to want (23c is c o l d).

My bedroom is 26sm and I have replaced an 18k unit with a 9k regular Panasonic (was intended just as a backup), but we like about 25c. This unit has no problem keeping room cool (ground floor so no heat buildup below) and has resulted in a 2,000 baht reduction in electric bills each of the last three months.

The advantage with inverter comes when using well less that max capacity so expect you will not see the benefits most people would get (who use a higher normal temp setting). But it may be worth the price difference for noise and more efficient operation (even if not up to advertising amounts).

[ClaudeFeller]

8000 THB seems a lot!

First you should buy a 12.000 BTU for a 18 m² room (if sun exposed and not very good insulated ceiling).

Second if you save 20 % on average 2.000 THB per month the pay back is after 20 months - very short period.

[kamalabob2]

I am not so sure if ELKANGORITO was serious about ending the 16 page thread on HOW MUCH DO YOU PAY FOR ELECTRICITY EACH MONTH.

To add my 2 baht to this AND to recommend a Home Owner consider INVERTER air conditioning I've attached a full months receipt for a larger home with too many appliances. We set the temperature at 26 degrees on the following air conditioners:

Daikin 18 K Inverter in a home office

Daikin 18k Inverter in a Home Theater

Panasonic 24 k Inverter in my daughters bedroom

Mitsubishi sb 24 K Wide and Long in Master Bedroom

Samsung 13K Regular in maids room bought 2nd hand from a fellow Expat making a quick exit from Thailand

Two Amena 13K Regular units in the Aerobics room (the two bedroom units moved from our former rental house)

LG 18K Regular Jet Cool Unit in Guest bedroom

The Panasonic Inverter Compressor Unit is more quiet than the same size Mitsubishi Compressor on the same 2nd floor terrace.

The Daikin 18K Inverter compressor is more quiet than one Amena 13K compressor on the same 2nd floor terrace.

Both Daikin and Panasonic Inverter interior units are very quiet and have been defect free.

NOT every air conditioner is used every day because we have at least one ceiling fan in every room.

We installed 36 Philips LED light bulbs in various standard interior and exterior light fixtures. We have 16 Panasonic Inverter florescent exterior veranda ceiling lights. There are four Panasonic Inverter ceiling lights in the Garage and Pump room building,

I had Philips T5 florescent lights installed in the Two step interior ceilings, the house attic and garage attic.

Most of the ceiling fixtures "down lights" we have 11 watt Osram Mini Twist bulbs installed.

The Panasonic Inverter NR-B41MV3 bottom freezer drawer Fridge is much quieter than the 3 year old LG side by side refrigerator.

We have a small swimming pool with an Onga spa pump and Onga Pool pump. The pool pump operates 7 hours a day. Three LED light fixtures in the pool.

Not exactly by choice we have an expensive 3 phase transformer on our property and I keep a weekly log of Electric meter readings in a book. I know Expats in this same small town who have had billing disputes with the Provincial Electric Authority.

We selected a Grey color roof tile, have CPAC ULTRA KOOL insulation, green tint tempered glass windows, black out curtains in many rooms, 12.5 thick exterior and 7.5 thick interior CPAC Autoclaved Aerated Concrete blocks. The major reason our home might stay cool is the 3.5 meter wide covered verandas on the ground floor and 1.7 meter wide covered veranda on the 2nd floor rear.

Many cooking and cleaning appliances. Too many home entertainment devices.

We are able to keep windows and doors open all day and at night since we have an electric fence from WASP SECURITY for perimeter security. I keep four exterior florescent lights on all night for security and ten LED interior lights on all night so we do not trip on any pet cats.

The eleven halogen decorative lights are rarely turned on.

One Mitsubishi Water pump and one Hitachi Inverter Water pump, operate less since we have a 500 liter pressure tank.

Six Stiebel Eltron DHA 4/8 electric multiple point water heaters for faucets and showers.

Electric lawn mower, and various electric tools.

My wife and daughter grew up in a small home in a village. I am extremely fortunate that they both are thrifty with electrical usage. Cooking FOUR MEALS EVERY DAY is on interior or exterior Gas HOB cook tops except for a rarely used Fagor Electric Oven. I paid PG & E electric and natural gas bills for 33 years in my name so I am very concerned with the energy efficiency of any electric item we purchase.

Manchester Mike would NOT regret purchasing a Daikin or Panasonic INVERTER air conditioner installed by an Independent shop that will give him a DISCOUNT (some shops in Buriram Province had insane prices at manufacturers list price or even above list price) including the installation. Our inexpensive Amena units seem to work fine since we really had them cleaned by our appliance shop every 6 months, but the Inverter models are much more quiet even being larger BTU units.

I spend an average of 93 baht a day on electricity living in a large home with low energy devices. 2778 last month was typical and that included some work crew here with drills, but not WELDING machines. No "landlord" padding the electric bill, no electric frying pans, no incandescent light bulbs, no CRT televisions.

July_2008_Electric_Bill_Buriram_Province287.pdf

[manchestermike]

Thanks for the responses so far. A few extra points.

I live in a condo on the 18th floor, the condo was completed mid 90's. I guess the levels of insulation are to the construction standard of that time. I live in a 2 bedroom 90m2 unit and have purchased the 45m2 studio next door to make it a 3 bedroom. My current electricity bill is approx 3k / month ( paid direct to the electricity authority ).

The new airconditioner is for the 'new extension' which has been partitioned into a large bathroom, walkin wardrobe and bedroom.

My existing 2 bedrooms are fitted with panasonic 13000 BTU units. These have operated for 3 years without any issues. The smaller room ( approx 14 m2 ) reaches temperature very quickly and is always cool. The larger master bedroom ( approx 19 m2 ) takes a long time to reach temperature but does maintain the correct temperature. The temperature settings are based upon the remote control reading I have never checked them with a thermometer.

The standard panasonic 15000 BTU unit was quoted at 28K from the high street shops and 21K from a smaller dealer. The inverter version was 36k on the high street and 29K from the smaller dealer. I would welcome any comments on a cheaper place to get the panasonic inverter unit in central bangkok.

Thanks to kamalabob2 for your comparison of the two units.

[youngkiwi]

Go for the inverter. They are far more efficient and cost less to run. Paying the additional cost for an inverter type is worth it in the long run.

[Naam]

Go for the inverter. They are far more efficient and cost less to run. Paying the additional cost for an inverter type is worth it in the long run.

not necessarily. "Lopburi" has spelled out the caveat:

quote: "The advantage with inverter comes when using well less that max capacity so expect you will not see the benefits most people would get (who use a higher normal temp setting). But it may be worth the price difference for noise and more efficient operation (even if not up to advertising amounts)."

[longball53098]

kamalabob2----------that's pretty impressive on the electric invoice for that many high wattage devices!

How you can achieve 92 baht a day is amazing!

I have a small 3 bedroom house with one LG 13k btu AC in the bedroom that runs an average of 8 hours a day on 26/27 setting.

I read and track the usage almost daily. We consume about 45 baht a day using the one AC and 3 or 4 showers a day with one water heater and the other small appliances. If we do not use the AC the usage drops to about 33 baht per day.

I can only believe that most of your AC units are not running most of the time and that the cooking is minimal.

[kamalabob2]

Cooking with Natural Gas at least four times a day. No electric clothes dryer but three Sanki Aluminum clothes racks. Fans are often on, air conditioners seldom on except prior to sleep. The "learning curve" went well for the Thai people in the family and staff to TURN OFF lights, appliances and home entertainment when possible. It has been suggested that the way the transformer and electric meter are "in line" on our property might be to my advantage, but I think using the fourteen interior ceiling fans has helped to keep the electric bill in check. Once we are finally done with work crews I know that bill can drop farther. Even lighting on the Spirit House is kept to a minimum. In APRIL all bets are off as it does get so darn hot in Issan!!

[tjo o tjim]

This graph shows the typical efficiency profiles for larger systems. The "No-Relief" is the absolute cheapest kind of unit; Relief is mid-range; ASD Relief is an inverter-based unit. Depending on what unit you are looking at as a base, the break-even point is usually at 80% or 90% load for the inverter unit. (The relief unit will never be less efficient, and is only equal at full load.)

If you need the full capacity to pull down room temperature fast, but have a well-insulated space that can easily maintain temperature, the inverter unit makes a lot of sense. If the load is fairly constant then you pay 10% more for the inverter unit.

So, for the bedroom, inverter makes a lot of sense. If you have an office that you use during the afternoon, the inverter will likely cost you a little more during the hot season, but will save you during the cool season.

Much of the value comes down to how you use the AC. If it is just when it is too hot to be bearable, the inverter doesn't help. If you use it all the time to pull down the humidity and temper the air, it can work well. If you have a well insulated, low-thermal mass house, it is a hands-down winner.