Lee Ah Mooi Uses A. O. Smith Heat Pump Water Heaters

Lee Ah Mooi Old Age Home, a leading provider of eldercare services in Singapore has recently upgraded their facilities for the provision of personalized and affordable healthcare. No longer using high consumption electrical water heaters, they have made the switch to heat pump water heaters to provide consistent hot water for their shower facilities, all while saving 75% on electrical running costs.
Water heater upgrading works took place in the wing above, which comprised shower areas, laundry room, and kitchens spread out over three floors. We explored two options of water heater placement and type.
  • Option A was to use central heater system, where large heaters were placed on the ground level and hot water piped to the entire building.
  • Option B was to use a micro heater system, where smaller heaters were placed above the ceiling close to the point of use.
Whether to use central heaters or micro heaters are dependent on several factors, most of which have to do with project layout. Key questions asked are:
  1. Is there sufficient space?
  2. What are the differences in product cost?
  3. What is the incremental piping cost?
  4. What are the differences in running cost?
1. Is there sufficient space?
Option A – large heaters require a bigger area of installation
Option B – Micro heaters are small and may be placed above false ceilings if there is one

2. What are the differences in product cost?
Option A – fewer units, lower product cost
Option B – more units, higher product cost

3. What is the incremental piping cost?
Option A – large heaters are placed far away from the point of use and require an additional recirculation loop (red pipes in diagram above) for hot water to reach users quickly
Option B – micro heaters are close to point of use, no need for the recirculation loop

4. What are the differences in running cost?
Option A – Having a recirculation loop means more heat loss to the environment and a higher running cost.
Option B – Although micro heat pumps are about 5% less efficient than central heat pumps, the heat loss from recirculation loop far outweighs this advantage.
Space constraints are a key determinant factor especially in Singapore, where every square inch is precious. The other factors are cost related and can easily be worked out. Here are some sample cost data based on this project.
After weighing their options carefully, Lee Ah Mooi went ahead with the Micro option, but there is no hard and fast rule as every job site and space requirements are different. Costs also vary with different projects.
This is what the water heaters look like installed above the false ceiling. They require a ventilation grille in the ceiling to allow for air circulation.
Heat pumps, like regular electric heaters are still controlled by the heater switch outside the bathroom. In Lee Ah Mooi, the heat pump control panel has been relocated to the top of the ceiling so users can easily see how much hot water is left in the tank. Users can also adjust the heat pump water heater settings with an infrared remote control.

To find out more about heat pumps and how they save energy for small organizations in Singapore, you may read more about our recent projects here:

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.