Energy Cost Of Residential Airconditioners (Single Phase Power)

Air conditioner is one of the electrical appliances which consumed high amount of energy at home. In order to save on energy bill in the long run, it is recommended to install an energy efficient airconditioner at home. Below is a list of brand of airconditioners which are available in the Singapore Market for home use. It shows energy cost per year and also the price to install a system 3. 

A properly maintained airconditioner should last at least 7-8 years on average taking into consideration the compressor which is the most expensive component has a 5 years warranty.

Comparison Table for System 3 

Annual Energy Cost is derived from 8 hours usage daily and Energy Tarrifs of 19.13 cents per kWh

Brand	Model	Green Ticks	Cooling Capacity (kW)	Full Load COP1,2	Part Load COP1,2	Weighted COP3	Annual Energy Consumption (kWh)4,5	Annual Energy Cost ($)4,6	CU Height	Standard HDB Price found online
Daikin	MKS65QVMG	5	6.15	5.07	6.36	5.84	2342	448	695 mm	S$3,220.00
Daikin	3MKS71FSG	3	6.89	3.82	4.66	4.32	3522	674	735 mm	S$2,925.00
Fujitsu	AOAG20LBTA3	4	5.78	4.37	5.72	5.18	2564	490		S$3,299.00
Fujitsu	AOAG24LAT3	2	7	3.7	5.5	4.78	3440	658	700 mm	S$2,635.00
Hitachi	RAM-68Q9	2	6.92	3.4	4.64	4.14	3837	734	750 mm	S$2,709.00
LG	A4UQ26GFA0	3	7.86	4.05	5.79	5.09	3457	661	655 mm	S$2,817.00
LG	A4UQ26GFA2	5	6.47	5	5.84	5.5	2523	483	655 mm	S$3,269.00
LG	A3UQ26GFA0	2	7.74	3.67	5.75	4.92	3673	703	655 mm	S$2,575.00
LG	A4UQ26GFA1	4	7.18	4.5	5.52	5.11	3031	580	655 mm	S$3,299.00
Midea	M3OA-21CDN1-QC4	2	5.83	3.44	4.27	3.94	3183	609	700 mm	S$2,019.00
Midea	SMKY-21-O-04	4	5.78	4.46	5.51	5.09	2529	484	700 mm	S$2,723.00
Mitsubishi Electric	MXY-3G28VA	5	6.12	5.01	6.43	5.86	2295	439	710 mm	S$3,461.00
Mitsubishi Electric	MXY-3A28VA, MXY-3A28VA-R7	2	7.31	3.36	5.17	4.45	3924	751	710 mm	S$2,834.00
Mitsubishi Heavy Industries	SCM60ZJ-S1	3	6.19	4.17	5.38	4.9	2803	536	640 mm	S$2,742.00
Panasonic	CU-3XS27RKZ	3	5.81	3.99	5.39	4.83	2716	519	695 mm	S$2,990.00
Panasonic	CU-3S27MKZ	2	7.44	3.41	5.11	4.43	3936	753	695 mm	S$2,614.00
Samsung	AJ21FCJ3EC	2	6	3.4	4.55	4.09	3300	631	638 mm	S$2,581.00
Sharp	AU-X3M24RV	2	6.99	3.53	5.26	4.57	3539	677	710 mm	S$2,737.00
Toshiba	RAS-3M20SACV	2	5.8	3.42	4.48	4.06	3241	620	695 mm	S$2,531.00
York	YPH3YC021BAMSA-X	2	6.06	3.52	4.32	4	3358	642	695 mm	S$2,188.00

1. Coefficient of Performance (COP) means the ratio of the total cooling capacity expressed in Watts to the total effective input power expressed in Watts.
2. Full load COP means the COP at 100% load, while Part load COP (applicable for inverter air-cons only) means the COP at 50% load.
3. Weighted COP = 0.6 x Part Load COP + 0.4 x Full load COP. Weighted COP is used to calculate the annual energy consumption and annual energy cost for inverter air-conditioners.
4. Annual energy consumption and annual energy cost include the standby energy consumption.
5. The actual annual energy consumption depends on factors such as room temperature, thermostat setting, frequency of maintenance etc.
6. The estimated annual energy cost may vary from the actual annual energy cost.
7. kW is approximately 3412 BTU/hr.

Brands Comparison of Energy Efficiency can be found on NEA's Website


https://e-services.nea.gov.sg/els/pages/search/publicsearchproduct.aspx?param=goods&type=p



Based on lastest energy Tarrifs from EMA website

https://www.ema.gov.sg/Residential_Electricity_Tariffs.aspx

Things to look out for when getting a new airconditioner in singapore for residential property

First of all when installing an airconditioner for your residential property, you will need to consider the following pointers besides just evaluating purely based on price. End of the day, it is neither the lowest price in the market that offers you the best value nor the most expensive price that gives you the most value.

1)How reliable are the people installing the aircon for you?
This can be found by looking at the number of years the company is in business and the track records which give them a higher credibility when they are involved in projects like installing airconditioner for school, government buildings or events before.

2) Are the installers Building and Construction Authority (BCA) trained?

Flat owner shall be responsible for the proper installation, safety and stability of the airconditioner. This is applicable to flats without an aircon ledge which requires the mounting of a stainless steel bracket to support the condensing unit. This is because the condensing unit posed as a safety hazard if it fall off as a result of improper installation by a non-qualified installer. BCA trained installer is also required to wear a safety belt when installing the condensing unit for flat requiring a stainless steel bracket to support the condensing unit. Therefore, you will need to engage a BCA trained installer to install for flat which requires a stainless steel bracket.

3) Is the company using its own installers or subcontractors?

Having a team of in-house installer means that the price you will be paying for does not inccur a third-party cost which translate to a better savings. Second and the most important reason is quality control when the company uses in-house installer and getting the same installer to go back to do any touch up or rectification work is easier. Don't have to go through too many channels and installer has a proper schedule to follow. It is much more difficult to get the subcontractors to go back for any post installation work as they are paid strictly based on assignments with less strings attached to the company who called for their service.

4) What are the installation materials used for the airconditioner?

Installation materials to look out for include insulation thickness, copper pipe tubing and drainage pipes.

For rubber insulation thickness, 3/8",1/2" and 3/4" are commonly available. Some companies will stick to one standard size of 3/8" insulation thickness only with no upgrade options.

For R22 refrigerant with exposed/surface trunking meaning you can see the white casing, 3/8" thick insulation is suffice if it is installed in HDB flats. If you are quite particular about sweating due to condensation issue and don't mind a thicker trunking size you can upgrade to 1/2" thickness rubber insulation.

For R410A refrigerant, 1/2" thickness rubber insulation is highly recommended due to a higher condensation as compared to R22 refrigerant. For concealed piping 3/4" rubber insulation will be recommended.

As for copper pipe tubing, a recommended thickness of gauge 23 (0.6mm thickness) is required. Having a thicker copper pipe wall of gauge 22 (0.7mm thickness) will be a plus due to a higher gas pressure for R410A ascompared to R22 refrigerant.

Drainage pipe size of 16mm diameter is recommended. Some companies might offer 13mm drainage pipe in order to cut cost which leads to a higher chance of water leaking from the fancoil.

5)How many years of installation warranty does the company covers?

As far as installation warranty is concern, installation warranty does not cover sweating due to condensation as there is no way to prevent condensation.

With the right sizing and thickness of insulation material used for the copper piping, condensation will be greatly reduced.

Installation warranty covers gas leaking from copper piping which is not joined or bend properly with proper bending tools causing a gas leak within the stipulated installation warranty period. Logically, with proper installation of the airconditioner by a qualified installer, you will not even be required to top up the refrigerant at all as the refrigerant is being recycled.

6) Does the company offers any value added services like extended warranty for the airconditoner?

Getting an extended warranty for your airconditioner is crucial as you can have a peace of mind when your airconditioner break down suddenly and also it can prevent others from overcharging you for any repair work rendered when you need to use the airconditioner. Nowsaday, electrical appliances are not make to last anymore. This is due to a lower production cost in mass production and place of manufacturing  thereby reducing the pricing and quality of the product.

7) Does the company offers any aircon servicing package?

Last but not least, prevention is better than cure. You will not want your airconditioner to be out of order in the middle of the night just like human beings falling sick when they are overworked and cannot work for a few days.

With regular servicing:

Water leaking from the fancoil can be prevented when the drainage pipe is cleared.

Malfunction of the airconditioner can be greatly reduced when it is not overworked and properly maintained. Your electricity bill will not shoot up suddenly as a result of the compressor running at a higher speed for inverter airconditioner and running non-stop for non-inverter airconditioner when it requires a longer time to cool down the room.

Aircon is as cold as new and the air you inhale is fresh.

The life span of the airconditioner can be prolonged.

What you need to know when installing an airconditoner in HDB flats in Singapore

Types of airconditoners available

Cassette, Wall-mounted, Floor/Ceiling suspended, Duct-Connected, window unit, casement and portable aircon.

Inverter vs Non-inverter

Inverter airconditioners are running on variable speed compressor thereby reducing energy cost as compared to non-inverter airconditioners which is mono speed (on/off) and runs at full load when the compressor runs.

The compressor of inverter airconditioner will reduce the running speed once the preset temperature of the airconditioner is achieved while non-inverter compressor only switches off when the preset temperature is achieved for a while before turning on again when the room temperature rises. Room temperature remains almost constant for inverter airconditioners as compared to non-inverter airconditioners which has a fluctuation in temperature.

Noise level of inverter condenser is greatly reduced as it is using a DC twin rotary compressor.

R410A refrigerant vs R22

R410A refrigerant is CFC free (environmental friendly) and has a operating gas pressure of 1.6 times higher than R22 refrigerant. R410A also has a higher condensation rate due to its slightly higher cooling of the refrigerant as compared to R22. On average, 30% of energy can be saved by getting an inverter airconditoner as compared to non-inverter airconditioner provided the airconditioner is being serviced regularly and cooling capacity of the fancoil is not undersize. R22 refrigerant is used in Non-inverter aircon and has a lower operating gas pressure

Single split means one condenser connected to one fancoil also known as system 1

System 2 means 2 Fancoils (Indoor units) connected to one condenser (Outdoor Unit)

System 3 means 3 Fancoils (Indoor units) connected to one condenser (Outdoor Unit)

System 4 means 4 Fancoils (Indoor units) connected to one condenser (Outdoor Unit) 

BTU is known as british thermal units and is a unit of measurement of thermal energy

Conversion from Kw to BTU. 1 kW= 3412 BTUs.

HP stands for Horse power. 1 HP is the power input equivalent to 746 W and can produce approximately 9000 BTUs

Typically fancoil units are available in 9000 BTUs (2.5 kW) 1 HP, 12000 BTUs (3.5kW) 1.5 HP, 18000 BTUs (5kW) 2 HP and 24000 BTUs (7kW) 2.5 HP. 1 HP = 746 w, 230 V at 50 Hz

To find out what is the sizing of the aircon required for the area you can take area size in square feet multiply by 65 or area size in square meters multiply by 650.

Example 140 square feet area size will require 140 x 65 =9100 BTUs

In this case you can select 9000 BTUs for the room as there will be furniture like built in cabinet or wardrobe occupying the space.

Rule of thumb for installing fancoil capacity in HDB flats.

Flat Type	Rooms BTUs	Living Room/Hall BTUs
3-room	9000 x 2	12000
4-room	9000 x 3	18000
5-room	12000 for Master bedroom 9000 for the rest of the rooms	24000
Executive Apartment/Maisonette	12000 for Master bedroom 9000 for the rest of the rooms	24000

*Living Room /Hall BTUs exclude kitchen area therefore preferably need to have a sliding door or curtain to block out the area to prevent the cold air from escaping if it is an open concept then you will need to get a higher cooling capacity or install one more fancoil at the kitchen area.

How many condensers can one HDB flat install?

It depends on the electrical loading of the flat.

Flats with 40 Amps main switch and flats upgraded

under Main Upgrading Programme (MUP)

Maximum of 2 split-type air-conditioner condensing

units (max. weight of 110 kg each) are allowed to be

installed externally.

(i) No control on running current of electrical appliances.

But to be restricted by the 20Amps DP isolater or

15Amps power point.

(ii) No restriction on number of casement/window unit air

-conditioners.

To check whether your flat has a higher electrical loading please visit the website below.

https://services2.hdb.gov.sg/webapp/BN31AWERRCMobile/BN31SElectrical?loadAction=electrical

HDB apartment blocks completed on or after 1 Jan 1994 are provided with a 40 amps main switch. Incoming electrical supply is also upgraded for blocks under the Main Upgrading Programme (MUP). Flat owners need not apply for an HDB permit to install an air-conditioner or other higher capacity equipment/appliances if the flat is provided with higher electrical loading.

For flats which do not have higher electrical loading they are flats provided with 30 Amps main switch . Only one condenser is allowed and the following guidelines are to be followed when installing a new airconditioner.

Flats with 30 Amps main switch

Flat Type	Max. Total Running Current Allowed	Air-Con Condensing Unit Max. Weight Allowed
1/2-room	5Amps	80kg
3/4/5-room/ Multi Generation	8.5Amps	80kg
Executive Apartment (with 4 bedrooms)	8.5Amps	80kg
Executive Apartment (with 5 bedrooms in converted block)	11 Amps	80kg