If you're looking for a smarter, more efficient way to produce hot water for your home or business, air source hot water cylinders are quickly becoming one of the best-value renewable options available across Ireland and Northern Ireland. They deliver high efficiency, low running costs and a cleaner, more sustainable alternative to traditional immersion heating or oil-fired systems.
This guide breaks down how they work, how much they cost, what they save, and whether they’re the right option for your property.
What Is an Air Source Hot Water Cylinder?
An air source hot water cylinder uses heat pump technology to extract energy from the surrounding air and convert it into hot water. Instead of burning fuel, it moves heat — making it up to three to four times more efficient than standard electric systems.
An ASHW cylinder includes:
- A compact heat pump unit (usually top-mounted)
- An integrated hot water cylinder
- Smart controls for efficiency
- A high-efficiency compressor
It’s a renewable alternative that offers year-round hot water — even when temperatures drop.
How Air Source Hot Water Systems Work
- The unit draws in ambient air.
- The heat pump extracts heat energy from the air.
- A refrigerant cycle boosts the temperature.
- The heat is transferred into the water cylinder.
- The system stores and delivers hot water on demand.
Because it moves heat instead of generating it, energy consumption is dramatically lower than immersion heaters.
Costs of Air Source Hot Water Cylinders in 2026
Pricing varies depending on cylinder size, installation needs, and whether the property is domestic or commercial.
Domestic Pricing
- Typical installed cost: £2,300–£3,800 (NI)
- ROI properties: €2,800–€4,200
- Suitable for 1-bed apartments up to 5-bed houses
Commercial Pricing
- Larger cylinders or multiple units: £4,000–£12,000+
- Ideal for hotels, B&Bs, care homes, HMOs, gyms
Factors affecting cost include:
- Cylinder capacity
- Ventilation requirements
- Existing hot water setup
- Electrical upgrades (if needed)
Running Costs & Energy Savings
Air source hot water systems reduce electricity consumption by up to 70% compared with immersion heating.
Typical savings:
- Home: £300–£650 per year
- Commercial: £800–£3,000+ per year depending on usage
They operate efficiently all year round and are significantly cheaper to run than oil systems for hot water generation. Many models are also compatible with solar, which can reduce running costs even further (e.g. a 250L cylinder can cost less than £1 to fully heat on an overnight tariff).
Grants & Incentives
Republic of Ireland (SEAI Grants)
- Support available for heat pump systems
- Eligibility depends on BER and property condition
- Can reduce overall cost significantly
Northern Ireland
- Local energy schemes or commercial grants may apply depending on the project
- Ideal for businesses looking to reduce carbon footprint
Is an Air Source Hot Water Cylinder Right for You?
An ASHW cylinder is ideal if you want to:
- Reduce energy bills
- Replace old immersion heaters
- Lower carbon emissions
- Add renewable technology with fast ROI
- Future-proof your heating and hot water setup
Great for:
- Homes
- Hotels & B&Bs
- HMOs & student accommodation
- Care homes
- Offices
- Retail units
- Gyms and sports facilities
Why Choose Gaia Smart Energy?
Gaia is one of Ireland and Northern Ireland’s leading specialists in renewable heating. We supply, install and maintain high-efficiency air source hot water cylinders tailored to your property. Every installation is designed for maximum savings, comfort and long-term reliability.
Get Your Free Hot Water Assessment
If you're considering switching to renewable hot water, we’ll assess your home or business and provide a tailored quote — no obligation, no pressure.
Traditional systems often require complex pipework or boiler integration. Air source cylinders with built-in heat pumps are easier to install, need only water piping, and come in sizes 80–250L. They’re also compatible with solar for even greater efficiency.
