Garden flats needing refurbishment.
100-150 square metres.
Refurbishment is a great opportunity to replace an old or existing gas boiler with an electric alternative. A garden may have additional flexibility allowing the installation of heat pumps. Depending on the condition of the heating system and your budget, you have three options:
Heat pumps are ideal for medium-sized properties and especially in the case of extensive refurbishment, Heat pumps work in properties with a reasonable level of insulation (not high). Therefore, the older the house, the more investment is required to bring them to the right level. On average, they will require more investment than other heat engines, but the opportunity of a refurbishment usually makes them worthwhile.
Approximate costs: £8,000 -10,000, including units, cylinder and installation and government incentives (currently £5000)
Option 2 is ideal for lighter refurbishments. If the heating system is in good condition and you may keep the radiators, a combination of a heat battery and a smart hot water cylinder can prove very effective,
You must check your incoming electricity fuse, as you will likely need at least 100 amps.
Approximate cost: £8,500
For very light refurbishments of well-insulated buildings, Infrared heating combined with a smart immersion tank bring the advantage of not tasking too much the electric fuse.
If installing infrared heating panels, the cost will probably be comparable to a heat pump.
If installing infrared thin film, the cost will be higher (hence only valid for very light refurbishments).
Approximate cost: £7-8,000 for infrared panels
£16-19,000 with plastered-in thin film infrared
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) will not have 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).