The ASA ruled that the advert was misleading after the energy supplier was unable to adequately substantiate the savings claim.
Scottish Power said the 20 per cent reduction was based on a trial of 70 homes by a third party between October and December 2011, but the ASA ruled Scottish Power was unable to prove a “causal relationship” between the smart product and gas consumption reductions through the trial.
It also said customers would misinterpret the findings presented in the advert to mean all 70 homes in the trial used the product more than once a week and achieved a 20 per cent drop in usage compared to other households. Only 60 per cent of the customers in the trial recorded this reduction and used the smart system at least once a week, compared to those in the trail using the product less often.
ASA found that a reduction in usage was not enough evidence to prove a savings reduction as the trial did not adequately control other factors to be able to make a direct comparison.
Scottish Power said in response to the investigation that it had already amended the advert to make it clearer the data showed that a user could reduce their gas heating usage by up to 20 per by using the product, but the ASA ruled that the advert must not appear in its current form again.