How Energy Saving is Your Water Heater?

After air conditioning, water heating is the second-largest energy consumer in households in Singapore. An average household spends about 20% of utility bills on water heating. Whether you are buying a water heater with the latest technology for your home or replacing a leaky old one, it pays to choose carefully.

Walk into the various electrical and bathroom showrooms in Singapore and you will see an array of water heaters proclaiming their green credentials. They can claim to save from 10% all the way to 80% of energy, but is this true? Unfortunately for the environment and the homeowner, it is soon discovered that most of it are just ‘greenwash’ churned out by a marketing department.
If you, as a homeowner, are serious about saving the earth, you will appreciate a straightforward comparison backed by facts and figures. So why isn’t this available in Singapore just yet? The answer is simple, we are all just waiting for a formal third-party ‘green’ rating and certification process to be set up here. But not to fret! If a green study like that has yet to be done in Singapore, we can easily draw parallels by using data from countries that are more advanced in this aspect.
One very good gauge of how much your water heating system can save is the Energy Factor or EF. The Energy Factor is an international standard that measures the amount of energy your water heater consumes. The higher the EF, the more energy-saving your system.
WATER HEATER TYPEIMAGEEFFICIENCY (EF)
Conventional gas storage water heater0.60
High-efficiency gas storage water heater0.65
Demand gas (instant gas heater)0.82
Min efficiency electric storage water heater0.90
High-efficiency electric storage water heater0.95
Demand electric (instant heater)0.95 (estimated)
Solar water heater (storage)1.20
Electric heat pump water heater2.20
Source: American Council for an Energy-Efficiency Economy

According to the table above by the American Council for an Energy-Efficiency Economy, an electric heat pump water heater is currently the most energy-saving system, with an EF of 2.20. Getting free heat from the air is less expensive than creating heat with heating elements.

A heat pump water heater requires much less energy than conventional systems like gas or electric water heaters by drawing ambient heat from the environment to heat the water.

What Is Your Water Heater’s Power Consumption?

To calculate your water heater’s power consumption, first determine the number of people in your family. Assume 2 showers a day.
usage of water heater per day
A typical Singaporean household of 4 will use the heater for about 2.67 hours a day. Use this Electricity Bill Calculator to find the monthly energy cost. Assume current tariff of around 31 cents (Nov 2022). You can get the most current Tariff at this website.
Sample computation of how much does water heater cost in Singapore.
A family of four uses around $77 to heat up a tank each month, that amounts to $930 a year.

Besides energy consumption, you should consider many other variables when getting a water heater, depending on your needs. These might include size, convenience and personal usage patterns. Always do your research before you make your purchases!

You can check out AOS Bath’s range of water heaters here.

More information on Energy Factor (EF) here.

Frequently Asked Questions About Energy-Saving Water Heaters

Why Do You Recommend Heat Pumps Over Solar?
Compared to solar heaters which have a heating efficiency of 50%, heat pumps operate at a higher efficiency of 80%. In Singapore’s unique climate, heat pumps are more popular because of their higher efficiency levels.
Renewable energy water heaters like solar and heat pumps are the most energy-efficient heating systems internationally. They have the highest Energy Factor (EF) of the various water heater types.
As a dedicated water heater specialist, A. O. Smith produces a full range of water heaters. Generation 1 heaters are the least energy-efficient with the lowest initial cost. Digital heaters are higher efficiency systems which offer you 10% savings, while renewable energy solar and heat pump heaters can save you 50-80% energy in total.
Electric water heaters: 3000W

Micro heat pumps: 210W

Central heat pumps: 460W

Heat pumps draw in plenty of free energy from heat in the ambient air. Micro heat pumps alone can save an estimated $600/year.

Top 3 Construction Mistakes in Landed Homes & How to Avoid

Changi Airport, Terminal 4 | AOS Bath Projects

Avoid Landed Home Nightmares!

Do you want to know the Top Construction Mistakes we hear about after owners shift in? You can avoid them all right at the start, during the construction phase. This can potentially save you so much money!

Problem 1: Roof is Dripping, But it's Not Raining!

The sky is clear, but water is mysteriously falling from your roof. What’s going on?

Mistake 1: Lack of Proper Drainage

Like an air con, a water heater drips water when running. If you have no proper drain point, that water will drip right off the roof, even on sunny days. That is really weird!

1-1 How to prevent this drip?

✅ Don't agree to a “free-flow” open roof. Always ask where the excess water will go.

✅ Have a drainage close to heater, within 1 meter, so that water can be neatly directed away.

Plan early. This can only be done during the construction stage.
Heater Installed in False Ceiling? You need to watch out for this mistake too.

Make sure your ceiling has a drainage point. Otherwise, water will always drip right onto your ceiling board and create ugly water patches!

Problem 2: No Hot Water in Some Bathrooms!

You step into your gorgeous new bathroom, turn on the tap, and… ice-cold water greets you. Meanwhile, the master bathroom is enjoying piping hot water. What is going on?

Mistake 2: Wrong Pipe Layout

If there is a mistake in pipe work of the hot water recirculation loop, some bathrooms will be blocked from getting hot water.
2-1 What is a Recirculation Loop?

It is a pipe loop that goes around the house. Hot water circulates through this loop.

Loop must be continuous.

Every bathroom tees off from the loop. This setup allows you to get hot water fast, compared to if you run a direct pipe from the heater to each bathroom.
2-2 Mistake: Loop is NOT continuous

❌ Will create dead zones, in blue. Dead zones will not get hot water.

Hot water will only run through the continuous loop, the yellow dotted part.

⚠️ To fix this, you’ll need to hack the walls. A very expensive and painful mistake.
As installers, we will test the heater to check if:

✅ Hot water is coming out at the heater. This confirms the heater is working.

✅ At least one bath has hot water. This confirms the circulating pump is working.

⚠️ If other baths do not get hot water, there is a pipe issue. Look for the person who did the pipes.
Even with experienced teams..

This Mistake Happens 30% of the Time

How Can You Prevent This?
Get more parties involved. Call your contractor, architect, and consultant to check and confirm that the loop is continuous.

The final responsibility is yours, if something goes wrong, you foot the bill! Make sure it’s done right at the start.
PDF: Schematic diagram, continuous loop

Problem 3: Ugly, Exposed Trunking on Your Beautiful Feature Wall

You've forked out a fortune for the a unique, textured wall.. only to have it ruined by a streak of cheap looking white casing running right across it. UGH.

Mistake 3: Forgot to Conceal Wires Early

Here is another mistake that happens way too often!

3-1 ❌ Forgot to Conceal Wire

The heater is at the roof and you are planning to place the control panel on the second floor. The panel wire is ready, but it has not been run and is left coiled up at the roof!

This wire must be concealed early, before the tiles are up. otherwise, you will get an exposed trunking right across your tiles. Unsightly!
3-2 How to Conceal Wire?

✅ Check, check, triple check that the wires are concealed

✅ If done right, you will see a wire box and the end of the cable hanging out out if.

✅ For best results, run only one wire in the conduit pipe.

Problem 4: Hidden Costs that Run into the Thousands $1000s of Dollars.

You were told that the installation would be $1000, but this figure ends up at $2000. What happened along the way?

Mistake 4: Forgot to Provide Compulsory Items

Before the renovation, you will get a checklist. Get these items ready early and you will save money. Here is how:
4-1 Gate valves
Negotiate for these early, and it will be included in the pipe work. If you forget and request for them later, it may cost you $150+
4-2 Isolator (Weatherproof Power Supply)
Be clear about the quantity and power rating early. Just like concealed wires, these need to be pre-planned.

If missed out, you will get:
❌ Ugly exposed wire tracks
❌ Higher chance of heater trips, no hot water!
❌ Long wait to get hot water
4-3 Scaffolding / Crane
Huge bonus tip that can save you One Thousand Dollars! If your heater needs to be lifted to the roof, you may need additional scaffolding or crane.

The good news is, you may not have to pay for these extras if you plan well. There is a good chance your main contractor or aircon supplier will be using this lifting equipment for other works.

Time your heater installation so that you can piggy back on scaffolding or the crane while it is at the site. This saves you a lot of time, and you don't need to pay twice. Do it early! If you miss the boat, too bad.

Don't Forget! You'll Have to Pay Penalties.

These 4 mistakes are all about 'forgetting'. It happens in 70% of houses. Don't be too trusting or naive to think it won't happen to you!

The good part is that they can be avoided. Here are some tips for your success.

✅ Double Check. Use the checklist, don't skip.

✅ Cross Check. Get others involved. Don't leave it to just one company or one person.

✅ Get Involved. You don't need to do everything, but at least watch out.

Construction Mistakes FAQ

Can my contractor install the heat pump?
Heat pumps are specialised heaters that require care and professional handling. It is best if your Heat pumps are installed by water heater specialists.
Installing a pressure pump in your home will certainly increase your water pressure but this is not legal in Singapore. This is because a pressure pump draws water pressure away from your neighbours.

If all your neighbours are experiencing water pressure problems, it is advisable to contact your Town Council or MCST for a solution.
The Climate Vouchers can only be used to purchase energy-efficient household water heaters like heat pumps.

Climate Vouchers cannot be used for other types of water heaters.
You can install heat pumps at any level of the house. The water pressure will not be affected.

You will get the maximum possible water pressure at your shower. This is because the heat pump is a pressurised storage tank.

You will only get lower water pressure if you are using an instant or gas water heater.