How Air or Ground Source Heat Pumps Change Your Radiator Requirements

Traditional Boilers vs. Heat Pumps

  • Traditional boilers burn fossil fuels to generate high-temperature water (typically 65°C to 75°C). Because the water is at such a high temperature, it can quickly heat a cold room using smaller standard-sized radiators.
  • Air or ground source heat pumps work entirely differently. To achieve maximum efficiency, they circulate low-temperature water, typically between 35°C and 55°C. Instead of short, hot bursts, they supply steady, continuous warmth but at a lower flow temperature—which means you need larger radiators to heat the exact same space effectively compared to the traditional boiler system

What This Means For Your Radiators (Delta 50 vs. Delta 30)

A common misconception is that a radiator has one fixed heat output. In reality, any radiator can have multiple different output ratings depending entirely on the temperature of the water entering it.

To standardise these differences, the heating industry uses an official measurement called "Delta" (ΔT), which represents the difference between the average water temperature inside the radiator and the air temperature of your room:

  • Delta 50 (ΔT50): This is the standard rating for modern boilers. It assumes your system runs with an average water heating temperature of 70°C in a 20°C room (70°C - 20°C = 50). Most radiators are sold using this Delta 50 number.
  • Delta 30 (ΔT30): This is the modern heat pump standard rating. It assumes your system runs on cooler, energy-saving temperatures with an average water heating temperature of 50°C in a 20°C room (50°C - 20°C = 30).

The Radiator Sizing Trap When Updating Your Heating System:
What happens if you connect your old radiators which were heated by a traditional boiler to a new Air Source Heat Pump (ASHP) or Ground Source Heat Pump (GSHP) system?

The cooler water flow temperature will automatically cut the radiator’s actual heat output by roughly 50% - 60% compared to its Delta 50 rating. To get the same room comfort, you must look at the radiator's specific Delta 30 performance, which requires 2 to 3 times more radiator surface area.

Timeless Style Meets Modern Efficiency: You don't have to compromise on your interior design. Our column radiator range offers a classic look that pairs beautifully with high-efficiency, eco-friendly heat pump technology.

Why Column Radiators Are the Solution:
To get the extra radiator surface area required for an air or ground source heat pump system, a column radiator is the ideal choice. The design places three, four, five, or six tubes deeply from front to back. This depth multiplies the metal surface area required, making it perfect for lower water temperature heating systems.

 Versatility for Your Home:

Our column radiator range will fit any room seamlessly, featuring:

  • 14 Heights: Ranging from 300mm to 2500mm, including the highly popular 600mm and 1800mm options.
  • 38 Width Options: Allowing you to find the perfect fit for any wall space or alcove while achieving the BTU output your room requires.
  • Countless Colours: Choose from an extensive palette of finishes to suit your interior style.

The Modern Option

Aluminium column radiators by Eskimo design.

These are an exceptional alternative to the standard column radiators mentioned above with a sleek modern appeal and outputs to rival. Designed specifically for low water temperature heating systems such as air or ground source heat pumps. Available in horizontal and vertical configurations, white and colours.

• Aluminium radiators hold significantly less water than steel. This means the radiator responds almost instantly when the heat pump starts circulating water.

•Aluminium transfers heat from the water within the radiator into the room much faster than traditional materials. This rapid transfer helps maximise the efficiency of your heat pump cycle.

•They deliver clean, contemporary lines and high BTU outputs, proving that eco-friendly, low-temperature heating can look sleek and modern.