High Heat Retention Storage Heaters Explained: EPC Scores, Real World Efficiency & Costs

High Heat Retention Storage Heaters: Are They Really the Best Electric Heating Option?

As UK households move toward electric heating solutions and seek ways to improve their Energy Performance Certificate (EPC) ratings, high heat retention storage heaters (HHRSHs) have grown in popularity. These modernised storage heaters are often viewed favourably on EPC assessments and are commonly recommended by assessors due to their classification as an “energy-efficient” electric heating technology.

But while high heat retention storage heaters may improve your EPC score on paper, the real-world picture is more complicated. From slow warm-up times and poor control to high upfront costs and bulky design, their day-to-day efficiency often falls short of expectations. Meanwhile, more advanced technologies—most notably infrared heating panels—remain undervalued by the EPC framework, despite offering better performance, comfort, and running costs.

In this blog, we’ll explore why high heat retention storage heaters are popular, how they work, the limitations of the EPC system, and why they may not be the most efficient electric heating option for your home.

Why High Heat Retention Storage Heaters Are Popular

Favoured by EPC Assessments

One of the biggest reasons for the rise in HHRSH popularity is the EPC scoring system. The framework ranks heating systems partly based on historic assumptions about electric heating, carbon intensity, and cost. Because high heat retention units are technically more efficient than older storage heaters, EPC software tends to reward them generously.

For landlords, housing associations, and homeowners targeting EPC band C or above, HHRSHs can appear to be the “safe” choice.

Seen as an Upgrade to Old Night Storage Heaters

Compared with the basic storage heaters of the 1970s-1990s, today’s high heat retention units do offer improvements:

• better insulation around the thermal bricks

• integrated fans for more controlled heat distribution

• smarter electric controls and timers

• reduced overnight heat loss

Because of these enhancements, they are marketed as a cleaner, more modern alternative to traditional electric heating.

Easy Swap for Electric-Only Properties

In homes without gas supply, HHRSHs are often suggested as a direct replacement for old night storage heaters. They work with Economy 7 or Economy 10 tariffs, making them an appealing choice for properties trying to make use of off-peak electricity.

But despite their advantages over older models, they still inherit many of the core problems of storage heating.

How High Heat Retention Storage Heaters Work

High heat retention storage heaters follow the same basic principle as traditional storage heaters:

1. They store heat overnight using cheaper off-peak electricity.

2. Ceramic bricks inside the unit absorb and hold this heat.

3. They gradually release heat during the day, often through a fan-assisted system.

Newer models have better insulation and improved heat control, but the fundamental process remains unchanged.

This “charge overnight, release during the day” method introduces several limitations that impact real-world comfort and efficiency—not all of which are captured in the EPC scoring system.

The EPC Framework: Why It Favours Storage Heaters (But Shouldn't)

EPC Assessments Use Outdated Assumptions

EPC methodology still relies heavily on data from the early 2000s, when electric heating was considered expensive, inefficient, and carbon-intensive. Modern technologies—such as far infrared heating—are not correctly recognised or scored.

Infrared heating panels:

• use 42% less wattage than electric radiators

• heat people and objects directly, reducing wasted energy

• maintain warmth after switching off

• are ideal for zoned heating, reducing whole-house consumption

Yet EPC software currently treats infrared panels the same as basic electric panel heaters, which dramatically undervalues their efficiency and affordability.

Why HHRSHs Score Well Despite Limitations

High heat retention storage heaters score well on EPC software because:

• They utilise off-peak electricity.

• They are considered “efficient” due to improved insulation.

• They are categorised as a modern electric heating system.

But EPC does not measure:

• actual running costs

• real-world comfort

• warm-up times

• energy wastage

• usability

• heat control

• the needs of people who work away from home during the day

So while HHRSHs may look good on an EPC report, they often perform poorly in everyday living conditions.

The Disadvantages of High Heat Retention Storage Heaters

1. Slow Warm-Up Times

Unlike infrared heating—or any on-demand heating—storage heaters cannot deliver immediate warmth.

• You must “charge” them the night before.

• They take all night to store heat.

• You cannot boost them instantly if the room feels cold.

This creates major usability issues during sudden cold spells or unexpected weather changes.

2. Poor Heat Release Timing

One of the biggest frustrations for users is heat release at the wrong time:

• They release heat gradually throughout the day, often when nobody is home.

• By the evening, when people actually want warmth, the heat reserve may be depleted.

• A warmer-than-expected day results in wasted heat — and wasted money.

Heating your home when you don’t need heat prevents true efficiency.

3. High Daytime Electricity Costs

If stored heat runs out, the heater must switch to day-rate electricity — which is significantly more expensive.

During winter, many households regularly “run out” of stored heat by mid-afternoon, forcing them to use costly electric top-ups.

This makes running costs unpredictable and often higher than anticipated.

4. Bulky, Heavy, and Unsightly

High heat retention storage heaters are:

• large

• intrusive

• difficult to reposition

• heavy due to their internal ceramic bricks

They occupy valuable wall space and often compromise interior design—unlike slim infrared panels that mount discreetly on walls or ceilings.

5. Limited Control & Precision

Compared to modern heating technologies, storage heaters offer poor controllability:

• Many lack proper thermostats.

• Temperature adjustments are basic and imprecise.

• They cannot respond instantly to your comfort needs.

• Users must “guess" how much heat they’ll need for the next day.

This lack of flexibility leads to wasted electricity and inconsistent comfort.

6. Heat Dissipation Even When ‘Off’

Even the more insulated units still release heat when not required:

• You cannot “store” heat for later.

• Warm weather wastes the previous night’s stored heat.

• They cannot adjust to fluctuating temperatures.

This is particularly inefficient in modern UK homes, which experience varied weather patterns through the year.

7. High Upfront Costs

High heat retention models are often £1,200–£2,500 per unit installed.

This is significantly more expensive than:

• infrared panels

• electric radiators

• or even replacing multiple panels or heaters

For landlords managing several properties, costs escalate quickly.

Why Infrared Heating Is More Efficient in Real-World Use

Despite EPC scoring limitations, infrared heating outperforms high heat retention storage heaters in almost every practical way.

Instant, Direct Heat

Infrared panels heat people and objects directly — not the air.

This means:

• no waiting

• no overnight charging

• no wasted heat

• warmth exactly when you need it

Precise Control

Infrared allows:

• room-by-room heating

• smart thermostats and scheduling

• perfect temperature accuracy

• heating only the areas you’re using

This reduces energy waste dramatically.

Lower Running Costs

Because infrared uses less wattage and operates intermittently (heating objects which then re-radiate heat), it costs significantly less to run.

Works with Standard Tariffs

No need to rely on Economy 7 pricing, which is becoming less favourable as day rates rise.

Ultra-Slim, Modern Design

Infrared panels are:

• thin

• lightweight

• wall or ceiling mountable

• available as mirrors or custom image prints

Perfect for modern interiors where bulky heaters are not welcome.

Better Heat Retention

Infrared warms the thermal mass of the room:

• walls

• floors

• furniture

These surfaces then release heat slowly, keeping rooms warm even after the heater switches off.

Storage heaters warm the air, which escapes easily.

So Why Are High Heat Retention Storage Heaters Still Recommended?

The short answer: EPC scoring.

But EPC scoring does not reflect:

• real household usage patterns

• varying work schedules

• the need for evening comfort

• the cost of day-rate top-ups

• efficiency in practice

• the comfort of radiant heat

• modern technology like infrared panels

As long as EPC software remains outdated, high heat retention storage heaters will continue to appear favourable—despite not being the best electric heating option for long-term comfort or cost-efficiency.

Final Thoughts

High heat retention storage heaters may look good on an EPC report, but for real-world living they come with significant limitations: slow warm-up times, poor temperature control, wasted daytime heat, bulky design, unpredictable running costs, and high initial expense.

In contrast, infrared heating offers:

• immediate comfort

• precise control

• lower running costs

• better real-world efficiency

• sleek, modern aesthetics

• compatibility with future electric grids

• heat where and when you need it

If you're looking for an electric heating system that performs well in daily use—not just on paper—infrared heating remains the superior choice.