Flats: 90-140 square metres
Just replace the boiler
"A boiler needs replacing", was the condition we originally set out to investigate and solve. Small flats without gardens or terraces that are not planned to be refurbished will be the most important category that will make or break our transition away from gas, one boiler at a time. For this to happen, we need cost-effective and unintrusive solutions.
Install a heat battery boiler, like the Tepeo ZEB, to supply hot water and heating. You remove the existing boiler and plug in this new one.
90 to 140 square metre flats should be just within the ZEB's energy capacity. If your property is not well insulated you should look at Option 2 below.
Approximate cost: £6000 installed
Install a heat battery boiler and a smart hot water cylinder to supply hot water and heating.
The addition of the smart water cylinder gives you more power output because the hot water is managed by a new machine, leaving the smart heat battery to deal only with heating. Option 2 also allows more flexibility of use and ultimately reduces your bills because you are almost guaranteed to charge only at night.
Approximate cost: £7800 installed
Avoid heat batteries by combining Infrared panels for heating and a smart hot water cylinder.
The infrared panels will be visible and typically installed on the ceiling. The installation entails some construction work: you may want to remove the radiators, and you will need to run cables to the infrared panels. On the other hand, infrared heating usually will not require upgrading the electric power supply to three-phase and does not have space or weight constraints.
Approximate cost: £7-8000 installed
One last thing, not needing refurbishment doesn't mean you can't attempt minimal improvements to the building itself. Replacing or increasing the loft insulation does not require any demolition. In some cases, very smart robots can also insulate under the ground floorboards through the undercroft. Depending on the condition of the heating system and your budget, you have one option.