Houses needing refurbishment.
50-100 square metres.
Refurbishment is a great opportunity to replace the old gas boiler with an electric alternative. Houses with gardens have the great advantage of outside space, where heat pumps and external units can be installed. Heat pumps should therefore be the default option, but because of costs and redundancies, smaller homes may not always be the best cases for heat pumps. You will find other options here.
Another aspect to consider is the extent of the refurbishment: a well-thought refurbishment project will, in fact, strike a balance between investment in heating systems and in upgrading the building to get the best return (lower bills and less carbon footprint) with the minimum effort.
Depending on the condition of the heating system and your budget, you have the following options:
Option 1
Heat pumps are ideal for medium-sized properties, 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 work 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
If the heating system is in good condition and you are not planning an extensive refurbishment you may decide to only replace the boiler. Install a heat battery boiler, like the Tepeo ZEB, to supply hot water and heating.
Approximate cost: £6000 installed
Option 3
Same as above, but combined with a smart water cylinder. The addition of the cylinder gives you more power output, more flexibility of use and ultimately reduces your bills because you are guaranteed to charge when the electricity costs less.
This option entails high peaks of demand during charging. Make sure to check your incoming electricity fuse, as you will likely need at least 100 amps.
Approximate cost: £8500 installed
Option 4
If your want to avoid the heat batteries, you can instead combine Infrared heating and a smart hot water cylinder.
Infrared heating can be visible (in the form of panels) or invisible when plastered into the ceiling.
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 infrared panels
£12-18000 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.
A pragmatic fabric-first approach suggests investing in insulation and draught-proofing in areas that make the most difference. The strategy will vary especially based on the age of the building. Pre-1930s buildings have no cavity walls and need to be handled more carefully. Fitting or increasing loft and ground floor insulation and draught-proofing or replacing doors and windows usually are the best investments.