This was always a topic of debate in my last employment simply because electrical storage and heating just didn’t seem to be moving forward with the world in terms of developments. The biggest problem we have is trying to control the storage and teaching our tenants how best to manage the outputs after storing the heat (if that makes sense).
We have all heard tenants telling us that they leave the input at 6 and the output at 6… this simply means full storage is discharged early in the day and then the tenant is required to plug a 2kW heater in in the afternoon, thus increasing the bills.
There are a number of organisations out there who seem to be telling us they have a solution to this. My preferred products were the electric boiler wet system which is rated at 9kW (can get larger). This is much better than 15kW loads on storage heaters. The other product is the one Martin Suggests above. Dimplex seem to have created a product that uses intelligence to help manage the heat output.
In terms of regulatory requirements and just as a word of caution. Check regulation 312 of the BS7671 – if you decide to increase the load from the design load which the distributor assumes is still the same, you run the risk of the infrastructure not supporting the consumer load. Only really applies in High or Medium Rise but is definitely something you need to consider if running a new contract to replace old for new.
Have a great weekend