The EPC score landlords have not heard of

Most landlords thinking about EPC compliance are focused on one thing: the band. Band D now, Band C by 2030. The familiar A–G scale has been in place since 2008 and the logic is straightforward — find the rating, find the gap, close it.

That picture is about to become more complicated. The methodology behind the EPC is being replaced. The new system — called the Home Energy Model, or HEM — introduces four separate scores instead of one. For existing properties, the equivalent is RdHEM, currently being developed on a parallel track. The final specification has not been published, but the direction is clear. One of those four scores is entirely new. It measures something the current system ignores completely.

It is called the Smart Readiness Metric.

What RdSAP cannot see

The current methodology — RdSAP — was designed in the early 1990s for a world of gas boilers, single electricity tariffs, and on/off thermostats. It records whether a programmer and thermostat are present. It does not distinguish between a 1998 programmable dial and a 2024 weather-compensating controller that learns occupancy patterns, adjusts flow temperature in real time, and responds to grid signals.

To RdSAP, those two things are the same. The smart controller is invisible.

This matters because modern energy technology — heat pumps, solar panels, battery storage, smart tariffs — operates in ways that monthly averaged calculations cannot capture. A heat pump running on a time-of-use tariff, pre-heating the building during cheap overnight hours, interacts with the grid in ways that are genuinely different from a fixed-schedule gas boiler. RdSAP has no way to credit that difference.

The Smart Readiness Metric is the proposed solution.

What the metric measures

The SRM evaluates how effectively a property can use smart controls, automation, and tariff-responsive operation to reduce energy demand and shift loads away from peak periods. It is assessed through HEM’s half-hourly simulation — 17,520 calculations per year rather than RdSAP’s 12 — which can model how a heat pump’s efficiency varies hour by hour, how a battery captures surplus solar and releases it in the evening, and how much of a property’s heating load can shift to cheaper, lower-carbon periods.

Three capability areas drive the score:

Smart control of heating. Zoning, weather compensation, flow temperature modulation, occupancy detection. Controls that match output to actual conditions rather than running to a fixed schedule.

Load shifting and tariff optimisation. Time-of-use tariffs, thermal storage, pre-heating using the building’s own mass, smart heat pump scheduling to run when electricity is cheaper and cleaner.

Demand response. The ability to reduce or shift load in response to grid signals, and smart EV charging — including, eventually, vehicle-to-grid export.

The government has proposed that a smart meter will be a qualifying condition for Band C on the SRM. Physical controls alone, on a flat-rate tariff, are unlikely to be sufficient.

Who this affects most

Properties with heat pumps are best placed to benefit. Heat pumps are inherently suited to load-shifting — they operate at lower power over longer periods, which means a significant portion of daily heating demand can move to off-peak hours without affecting comfort. A heat pump with weather compensation, room zoning, and a time-of-use tariff registered is a fundamentally different proposition to the same heat pump running on a fixed schedule with a flat-rate tariff. The SRM is designed to recognise that difference.

Properties with solar panels and battery storage also stand to benefit more accurately than under the current system. RdSAP credits solar generation in a limited way. Half-hourly simulation can model the full interaction: generation profile against demand pattern, battery charging and discharging, net grid import reduced. Technologies that are currently undervalued by the rating should be rated more accurately.

Properties with no smart controls — manual thermostats, no tariff flexibility, on/off boilers — will score poorly. The SRM measures the gap between standard operation and what smart optimisation would deliver. No smart capability means no gap to bridge.

What is not yet confirmed

The RdHEM specification for existing homes is still being developed. The thresholds that define Band C on the SRM have not been published. The proposed dual-metric framework — Band C on fabric as mandatory, plus Band C on either the heating system metric or the SRM at the landlord’s choice — is the stated direction but not yet confirmed in statute.

What is known is the direction. The current system does not reward smart operation. The replacement system will. Properties that can shift load, respond to grid signals, and interact with time-of-use tariffs will score better than those that cannot. That will not change regardless of where exactly the Band C boundary is drawn.

The practical implication now

For landlords already planning retrofit work, the SRM introduces a consideration that did not exist under RdSAP: controls and tariff capability may count alongside physical measures. A property with a heat pump installed may be able to reach Band C on the SRM through controls upgrades — weather compensation, zoning, time-of-use tariff registration — rather than fabric work alone. The relative cost of that route, once the thresholds are published, will determine whether it is viable.

For properties without heat pumps or solar, the SRM is unlikely to offer a compliance shortcut. The heating system metric or fabric improvement will be the primary routes.

The 2030 deadline has not moved. But the methodology being used to assess compliance in 2030 is not the methodology being used today. Understanding what is coming — even before the final specification is published — is part of making the right decisions now.