11 St. Swithun’s Terrace

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11 St. Swithun’s Terrace
Energy Graph
Emissions Graph


Address: 11 St. Swithun’s Terrace, Lewes, BN7 1JU
Owners: Liz Mandeville and Mike Jones
Type: terraced
Built: 1900
Beds: 3
Walls: solid brick at front, cavity unfilled rear
Residents: 2 adults

Eco Features

Solar Thermal hot water
Solar PV (1kW, West facing)
Wood burning stove (3.3 kW)
Loft Insulation (250mm)
Underfloor insulation (200mm)
Low energy lighting
Secondary Double glazing


This building demonstrates how far emissions can be reduced for a simple house, by employing the most cost-effective measures. Solar panels for hot water were installed several years ago, along with a highly insulated hot water tank. Recently a 1.05 kW PV array was added to help offset the already frugal electricity use. Window heat losses, always a problem with sash windows, were sensibly managed by relatively inexpensive secondary glazing, which also cuts out draughts. The ground floor has been insulated from below, thereby cutting heat losses and, again draughts. Liz and Mike further minimise emissions by using a woodburning stove in the sitting room as the main evening heat source, which displaces gas with near carbon-neutral fuel. Setting the internal thermostat to modest levels, and good insulation and renewables, result in a building with CO2 emissions that are an impressive 90% below the norm.

Summary of present energy regime

Gas boiler – approx 20 years old
Gas cooker/electric kettle
Solar HW (installed Jan 2008)
Wood-burning stove (3.3kW max)

Insulation etc.

Loft insulation - upgraded over past 20 years to keep pace with standards (now 250 mm glass fibre wherever possible).
Insulated HW tank (180 litres, replaced when solar HW installed).
Secondary double glazing on sash windows - main rooms 2005, rest 2008.
Underfloor insulation (under suspended wooden floor) - glass fibre.
Draughtproofing/control of ventilation.
Low energy bulbs.
Advised against filling cavity wall (age of house etc) but exposed areas are not huge.

Energy Usage (kWh per year)   Cost
  2004-06 2008-9 (year to March 2009)
Gas 13,250 5,250 £267
Electricity 1,600 1,200 £218
Logs n/a 2.5m3 £190
Total     £675


For general heating, we aim for a background temperature of 16 to 18C. The wood stove provides comfort heating in the evenings and also helps to heat the rest of the house, which remains at a reasonable temperature until the next pm.

In winter months, during the past year, we have put on the boiler for only 1-3 hours in early evening; this makes the best use of winter sun with the solar water heater. From March to October we only use the boiler as an occasional back-up for the solar HW system.

The ‘cost’ includes standing charges etc. The electricity and wood are from renewable sources.


11 St. Swithun’s Terrace
11 St. Swithun’s Terrace
11 St. Swithun’s Terrace