Flats needing refurbishment.
50-100 square metres.
Refurbishment is a great opportunity to replace the old gas boiler with an electric alternative. Depending on the condition of the heating system and your budget, you have three options:
Approximate cost: £6000
If the heating system is in good condition you may decide to only replace the boiler. Install a heat battery boiler, like the Tepeo ZEB, to supply hot water and heating.
A different combination: infrared heating and smart immersion tank. Infrared panels will be visible (and cheaper); instead, the infrared heating mesh can be plastered into the ceiling but will be more expensive.
Infrared panels £7,000-8,500
Plastered-in infrared thin film: £10-14,000
What else can you do?
The power required to heat the house ultimately depends on how well-insulated the building is and how efficient the heating system. It makes sense to address the building fabric and the heat engine simultaneously: improving the fabric reduces energy requirements, and the cheapest energy is the one you don’t use.
Fabric first: Old buildings (pre-war) have no cavity walls. Insulating walls from the inside can be tricky and expensive. Our advice is to advocate fabric improvements at the scale of the building to improve walls from the outside (where possible) and the roof. Instead, you can replace the windows and doors and improve air tightness by checking and insulating all the penetrations (pipes and ducts going out).