For a single home:

Level 1
10% better than Part L1A: 2006

Level 3
25% better than Part L1A: 2006.
Enhanced performance from conventional approach

Level 4
44% better than Part L1A: 2006.
As level 3 but with some on-site renewables.
Can be achieved with solar hot water collectors

Level 5
100% better than Part L1A: 2006.
As level 4 but with on-site renewables sufficient for all of heating, hot water, lighting, fans and pumps. Requires both heat and electricity from renewable energy sources

Level 6
Super-insulation standard, plus renewable energy for appliances and plug demands, as well as renewables to meet Level 5.

Typical upgrade path:

Level 1
Walls U-values 0.2 W/m²K
Windows U-value 1.6 W/m²K

Level 3
Walls U-values 0.18 W/m²K
Windows U-value 1.4 W/m²K
Air permeability 5m³/h/m² at 50Pa

Level 4
As 4m² of solar hot water panels

Level 5
Low energy lighting throughout
5kW wood pellet boiler
1.5kW of photovoltaics

Level 6
Wall/roof/ground U-values of 0.11 W/m²K
Window U-value 0.7 W/m²K
Air permeability 1m³/h/m² at 50Pa
90% heat recovery ventilation
2kW wood pellet boiler
4kW of photovoltaics

Energy Use

The energy use has been calculated using an adapted SAP method. SAP (Standard Assessment Procedure) is the calculation method used for the energy assessment for checking Building Regulations compliance for dwellings. The heating energy is calculated using a degree day method.

SAP has been adapted as follows:

• 100% low energy lighting rather than 30%
• 0% secondary heating rather than 10% electrical
• 88% heat recovery efficiency rather than 66%
• specific fan power (SFP) of 0.92 W/l/s rather than 2 W/l/s
• 2940 kWh/yr solar thermal (calculated by manufacturer) rather than 1475 kWh/yr
• water heating based on reduced shower water flow rate

Lighthouse Energy Use

The energy cost of running the Kingspan Lighthouse would be about £31 per year for the wood pellets, assuming wood pellets cost 1.8 p/kWh. The electricity is free, from the sun! A house of the same size and shape but built to 2006 Building Regulations standards would cost about £500 a year in energy bills.

Most of the domestic hot water energy is provided by the solar thermal panels. There is a small amount of Carbon Dioxide emissions associated with the growing, processing and delivery of the wood pellets for the remainder of the hot water and for the space heating. This is offset by extra renewable electricity that is generated from the sun by the photovoltaic panels and exported to the grid.

* In this way, the house is Net-Zero Carbon on an annual basis.

Operational Energy Use

This chart compares the estimated energy use for Lighthouse with benchmarks and measured data.

The Building Regulations estimates were done for a similar size and shape house designed to Building Regulations standards for 2006 and for 2002. Leicester is measured data for a residential home development for old aged pensioners, which was built in the mid-1990s. The 2001 national data is measured data averaged over all the housing stock in the UK.