8 Tips for Choosing the Best Gas Water Heater for Your Condo
8 Tips for Choosing the Best Gas Water Heater for Your Condo
1. Introduction
External gas water heaters are tankless, instantaneous systems designed for outdoor installation. Often referred to as outdoor gas water heaters or on-demand water heaters, these units are ideal for Singapore’s compact urban spaces. They do not require an indoor flue system, simplifying installation while ensuring safety and reducing the risk of carbon monoxide (CO) poisoning. These heaters are available in Town Gas (City Energy) or LPG (Union Gas) options and require an existing gas supply or additional infrastructure for new installations. Using condensing technology, they reduce operational costs and environmental impact while delivering high volumes of hot water.
2. How Exterior Tankless Hot Water Heaters Work
Singapore’s external gas water heaters use condensing technology, recovering latent heat from flue gases to achieve efficiency exceeding 100%, reaching up to 105%. This process lowers exhaust temperatures (35–50°C) and reduces energy consumption by 16% compared to non-condensing models. Units are weatherproof (IPX5D-rated) and produce hot water only when needed, minimising fuel costs and reducing NOx (Nitrogen Oxide) emissions.
3. Key Features & Benefits
- Space-Saving Design: No bulky storage tanks; wall-mounted for outdoor use.
- Durability: Copper heat exchangers or stainless steel to resist corrosion.
- Safety: Outdoor installation eliminates indoor CO risks.
- Flow Rates: Ranges from 16L/min to 24L/min, suitable for diverse needs.
Available Models by Flow Rate:
16L/min models:
- Rinnai REU-16189-RS
- Ferroli GS 16 OTE TG(I)
- Macro MA-16WOD
20L/min models:
- Rinnai REU-2208W-RS
- Rinnai REU-2024W-RS
- Macro MA-20WOD
- Ferroli GS 20 OTE TG(I)
- Ferroli GS 20 OE TG(I) 4G
24L/min models:
- Rinnai REU-2426W-RS
- Temperature Range: Adjustable from 35°C to 60°C (up to 85°C for commercial models).
4. Flow Rates & Usage Guidelines
Aligned with Singapore’s PUB WELS standards (see guidelines):
- Showers: 5–7 L/min (2-tick compliant).
- Bath/Basin Taps: 2–7 L/min.
- Kitchen Sinks: 4–6 L/min.
Tip: Calculate total demand using a diversity factor (not all outlets used simultaneously). For example, if a household has two showers (7 L/min each) and a kitchen sink (5 L/min), the total flow demand is 19 L/min. However, using a diversity factor of 0.7 (assuming not all outlets run at once), the required heater capacity is 13.3 L/min, making a 16L/min unit sufficient.
5. Temperature Rise (ΔT)
Singapore’s inlet water temperature averages 25–30°C. For a comfortable shower (38–40°C), a ΔT of 20–30°C is required. Units efficiently deliver this rise, even during peak demand.
6. Advanced Features
- Internal Recirculation Pump: Reduces wait time for hot water by pre-heating lines (“pre-heat mode”), ideal for distant installations.
Models with Built-in Pump:
- Rinnai REU-2024WP-RS
- Macro MA-20WODP
- Ferroli GS 20 OE BIP TG(I)
- Ferroli GS 20 OE BIP TG(I) 4G
- Cascade Systems: Commercial models (50kW–300kW) support large-scale applications like hospitals or hotels.
7. Commercial Solutions
For high-demand settings, 50kW or 100kW commercial units can be cascaded (up to 300kW). These include ABS weatherproof casings and optional integration with DHW storage tanks.
8. Compliance & Safety
- Mandatory by law: Gas (Supply) Regulations 20 (Installation of gas appliances) and 21 (Testing of gas appliances).
- IPX5D Rating: Protects against heavy rain and humidity.
- Certifications: Installation must be performed by Licensed Gas Service Workers (LGSW) in compliance with Singapore’s SS 146:2022 standard for gas appliances and PUB efficiency regulations.
- Gas Safety Advisory: Gas leaks at joints and reusing old parts like unions and gas valves are the main causes of gas leaks. Insist on new fittings for every installation or replacement.
Summary: Why Choose External Gas Water Heaters in Singapore?
External gas water heaters offer energy efficiency, space savings, and safety for Singapore’s urban homes and businesses. Key advantages include:
- Condensing Technology: Over 105% efficiency with low NOx emissions.
- On-Demand Hot Water: Eliminates standby energy loss.
- Versatility: Suitable for HDB flats, landed properties, and commercial sites.
- Compliance: Meets PUB WELS standards and weatherproofing requirements.
For households, models like 16L/min or 24L/min units balance cost and performance. Commercial users benefit from cascaded systems for large-scale demand. Always opt for professional installation by licensed gas technicians to ensure compliance with SS 146:2022 and other local regulations.
Life by City Energy online store has stated first in the list that “Please note that gas water heaters can only be installed by a Licensed Gas Service Worker (LGSW)” and “All installation work is subject to compliance with requirements from local authorities.”
The statement “The prices quoted are for the supply and delivery of the gas water heaters only” indicates that they do not provide installation services.
Explore authorised dealers like City Gas or Union Gas and consult licensed professionals for tailored solutions.
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