Background
This ruling forms part of a wider piece of work on advertising for greener heating and insulation products. The ad was identified for investigation following intelligence gathering by our Active Ad Monitoring system, which uses AI to proactively survey ads in specific sectors. See also related rulings published on 4 March.
Summary of Council decision:
Two issues were investigated, both of which were Upheld
Ad description
A paid-for Meta ad for British Gas, seen in May 2025, included an image of a person standing next to a heat pump and superimposed text stated, “Go greener and lower your bills. Save up to £546 with a heat pump and our exclusive tariff”. Text beneath that stated, “Switch to a heat pump and start saving With British Gas”. The caption stated, “Upgrade to a low-carbon heat pump and you could save up to £546. Savings based on year 1. T&Cs apply”.
Issue
The ASA challenged whether the:
- claim “Save up to £546” was misleading and could be substantiated; and
- ad omitted material information.
Response
1. British Gas Services Ltd said that the savings claim was presented as an “up to” figure, which indicated that a significant proportion of consumers were able to achieve that level of saving, rather than suggesting that all would. Their target market was consumers looking to retrofit their home with an air source heat pump after their gas boiler reached the end of its life.
They explained the £546 saving had been derived from a model that estimated a customer’s energy bill savings after switching from a boiler at the end of its life to an air source heat pump and joining British Gas’s heat pump energy offer tariff rate, and it demonstrated that a significant proportion of consumers could achieve the advertised rate of saving. The model was based on assumptions around pre-and-post installation energy usage, tariff types – the default tariff subject to the price cap which reflected what the majority of consumers were currently on, heating system efficiencies, assumptions regarding the use of gas and electricity for cooking purposes, and the effect of removing the daily standing charge for gas. Pre-installation energy usage was based on calculations from the Office of Gas and Electricity Markets (Ofgem)’s 2023 Typical Domestic Consumption Values (TDCVs) for medium-usage households, which was based on median energy consumption usage for properties across the UK. They explained that was the best way to estimate likely energy usage as the figures were based on a large dataset, which ensured accuracy and representativeness, and realistically reflected typical household consumption. They said, as a significant proportion of their customers needed to achieve the savings claim, it was appropriate to base the claim, in relation to pre-installation energy usage, on a property with medium energy usage. The TDCV rates were designed by Ofgem for energy suppliers and price comparison websites to use when a consumer’s actual annual consumption was unknown. They said the savings claim was made in relation to different methods for heating and hot water in a home and was not a comparison against any of their competitor’s prices or their products.
To validate the assumptions in the initial model, they supplied an additional breakdown of modelled data based on actual customer heat pump installations, which identified customers who had a heat pump installed by British Gas since the offer launched and had an electricity account with British Gas making them eligible for the heat pump energy add-on. The data compared predicted energy usage and rates for heating over a 12-month period from the date of installation, comparing the continued use of the customer’s boiler against the use of a new heat pump system. Details about the customer’s property were also collected through the pre-installation survey process, which included the efficiency of their current boiler and the Seasonal Coefficient of Performance (SCOP) of the proposed air-source heat pump system. From those calculations, 34% of customers achieved the £546 saving stated in the ad. British Gas believed their approach was consistent with previous ASA decisions.
2. British Gas stated that space restrictions in the ad meant that full details explaining how the savings claim was calculated were not included. They highlighted the ad stated, “T&Cs apply” and that consumers who clicked on the link were directed to their landing page which provided full details.
Assessment
1. & 2. Upheld
The CAP Code stated that price claims such as “up to” must not exaggerate the availability or amount of benefits likely to be obtained by the consumer. The Competition and Markets Authority guidance ‘Marketing green heating and insulation products: Consumer law compliance advice for businesses’ (the CMA Guidance) stated that “up to” claims should reflect that at least a significant proportion of consumers would be likely to achieve the stated outcome. Where relevant, they should also reflect the range of factors that impact product performance. The ASA had regard to the guidance in assessing the ad against the CAP Code.
We considered consumers would understand the claim to mean that a significant proportion of consumers could save £546 on their energy bills in the first year after installing a low-carbon heat pump and signing up to the British Gas tariff. We acknowledged that British Gas had based the savings claim on different methods for heating and hot water in a home, according to modelled criteria. However, the ad did not disclose that its savings claim was modelled, nor what the model’s criteria were. We assessed the ad, and the supporting substantiation that was provided, in relation to the ad’s specific overall presentation. We considered that the consumers who would be viewing the ad would likely be paying an existing energy bill and that context would impact their understanding of the ad’s savings claim, which referred to British Gas’s “exclusive tariff”. That meant the significant proportion of consumers who were able to save £546 were able to do so regardless of their current energy supplier or what heating device they used prior to having a heat pump installed and signing up to British Gas’s tariff.
We reviewed the summary of the modelled data used at the time the ad was launched (the initial modelled data) and the additional modelled data obtained during the subsequent validation process that British Gas provided.
The initial modelled data was underpinned by assumptions around energy rates and usage; cooking fuel; gas standing charge removal; heating system efficiency; and tariff types.
Pre-installation energy usage was based on calculations from the Ofgem’s 2023 TDCVs, for medium-usage households, estimated to be 11,500 kilowatt-hours (kWh) per year (31.5 kWh per day) for gas and 2,700 kWh per year (7.39 kWh per day) for electricity. The TDCVs were industry standard values for the annual electricity usage of a typical domestic user. However, the ad itself did not make clear its specific claim was only based on households with median energy usage. From that position, we considered the evidence that needed to be held to substantiate the specific claim as it was presented in the ad should demonstrate that the median energy usage parameter was representative of British Gas’s actual customers, which we had not seen was the case.
The data was partly based on the assumption that a significant proportion of consumers stopped using gas entirely following the installation of a heat pump, which would in turn eliminate the daily standing charge for gas. This was based on British Gas’s understanding that more UK households used electricity than gas for cooking. However, the ad itself did not make that clear. Further, the ad was for a product designed to replace a home heating system which did not necessarily remove the need for a gas supply within the home. In that context, we had not seen evidence that demonstrated stopping using gas entirely was representative of British Gas’s customers.
Regarding the pre-existing boilers that British Gas had compared the usage and efficiency of their heat pumps and tariff against, the data had assumed that consumers had a boiler with a ‘D’ energy efficiency rating. However, the ad had not made that clear and we had not seen evidence that outlined that ownership of that type of boiler was representative of British Gas’s customers.
The modelled data obtained during the subsequent validation process was based on actual customer heat pump installations and covered two scenarios: the expected heating costs if a consumer continued using their existing boiler, while also accounting for their boiler’s efficiency; and the expected heating and hot water costs with the new heat pump system, based on its Seasonal Coefficient of Performance (SCOP), a system used for measuring heating efficiency in heat pumps by replicating seasonal use. We understood the data was not held at the time the ad was published, which was a requirement under the Code. It outlined the rates British Gas’s customers were being charged before and after having a heat pump and joining British Gas’s tariff. Within the scenario that British Gas had modelled, 34% of 194 customers achieved the savings claim in the ad, with some expected to also incur higher bills after insulation.
Regarding the tariff type parameter, the initial modelled data and the data obtained during the subsequent validation process had based calculations on a default price cap tariff prior to heat pump installation, and we acknowledged the majority of consumers had their energy provided at that rate. However, neither dataset had accounted for customers who may have been on alternative tariffs from another supplier before switching to British Gas’s exclusive tariff. We therefore did not consider them adequate substantiation for the savings claim as it was presented in the ad, which did not disclose that the claim was based on customers being on the standard variable tariff and, in that context, how it was likely to be subsequently understood by consumers.
We considered that the basis of the savings claim, including that the savings figures were modelled and the assumptions underpinning it, was material information that was likely to affect a consumers’ understanding of the ad’s overall message. It was therefore required to be stated in the ad, so that consumers could proceed further into the consumer journey of obtaining a heat pump and joining British Gas’s tariff in an informed manner. We further considered the ad was not limited by time or space to such an extent that the information could not be provided. While the ad stated, “T&Cs apply” and its landing page, one click away, featured the £546 savings claim and included a footnote that explained the model’s parameters and assumptions, consumers did not need to read all the information on the page in order to proceed through the process of obtaining a quote for a heat pump installation with British Gas.
As the savings claim was based on specific circumstances, which were undisclosed in the ad, and the evidence provided, assessed in regard to how the average consumer was likely to interpret the ad, did not demonstrate that a saving of £546 on their energy bill could be achieved by a significant proportion of consumers in their first year after installing a heat pump. We, therefore, concluded that the ad omitted material information, and the savings claim as it was presented had not been adequately substantiated.
The ad breached CAP Code (Edition 12) rules 3.1, 3.3 (Misleading advertising), 3.7 (Substantiation), 3.9 (Qualification), 3.17, 3.22 (Prices) and 3.38 (Price comparisons).
Action
The ad must not appear again in the form investigated. We told British Gas Services Ltd to ensure they held suitably robust evidence to demonstrate any “up to” savings claims could be achieved by a significant proportion of consumers. We also told them to ensure their ads included all material information, which, in ads for heat pump installation with a savings claim, included qualifying information about the type of installation, any complexities that the savings claim was dependent upon, or if referenced figures were modelled.
CAP Code (Edition 12)
3.1 3.3 3.7 3.9 3.17 3.22 3.38
