“We bought the house in 2008, and deliberately chose a south-facing house that had not been touched for some years, as we were keen to do an energy-efficient renovation and to install solar renewables. We set a target of a 60% CO2 reduction, and commissioned an energy options analysis from Parity Projects. Parity suggested that we should increase the loft insulation to 270 mm, draughtproof windows and doors, install underfloor heating, put in a new condensing boiler with TRVs and install 100 mm of internal insulation to the ground floor and all external walls. This analysis showed that we were losing 29% of energy to draughts, as compared with a UK average of 15%! It also indicated the benefits of double-glazing the windows on the north side of the house. We chose our options from this list, and added in some more ideas of our own.“
ROOF, WALLS AND FLOORS
The attic was insulated with 270 mm of Knauf Loftroll over 60% of its surface, and over the other 40% 50mm of Kingspan insulation boards to facilitate storage.
The ground floor insulation comprised 65 mm of Kingspan TP10 board placed between the joists and under the underfloor heating tray, a layer of ply and an engineered wood flooring.
We installed 55 mm of Kingspan insulation board behind battens and plasterboard to internally insulate the front and back bays.
The side wall was insulated externally with 50 mm of phenolic insulation board covered with 8 mm of polymer render.
WINDOWS AND DOORS
All seven windows on the north side of the house were replaced with new low-E coated double-glazed units; there was sufficient depth to re-use the old window boxes.
Three other windows have been replaced completely, using double-glazed sashes, where the boxes were rotting or damaged.
All other windows were repaired where needed, draughtstripped, and had their ironmongery replaced.
All internal doors were overhauled and we ensured that they shut properly.
New double-glazed patio doors were installed in the kitchen and sitting-room.
The 20-year old boiler was replaced with a Worcester Bosch Greenstar system boiler, and a new hot water cylinder fitted with dual coils to accommodate solar-heated hot water.
Underfloor heating with two zones was fitted to the ground floor, and new radiators to the first floor.
We have installed 12 solar panels on the extension roof, giving 2.82 kWp capacity.
We also installed a 25-tube evacuated tube solar hot water system; this means that we can turn off the boiler between early May and late September.
LIGHTING / APPLIANCES
Energy-efficient bulbs are in use in most places, 5.5W LED bulbs have replaced halogen ones on the track in the kitchen, and 11W LEDS are installed in the showerroom ceiling.
We have installed a rainwater harvesting system which diverts rainwater from the extension roof, and feeds two WCs and a washing machine via an 800l holding tank in the patio.
Natural or recycled materials have been used wherever possible; an example is the glass-fibre loft insulation which is manufactured from 70% recycled material.
Ventilation is entirely natural – achieved by opening and shutting windows!