“The house had had a loft conversion in the 1960s, with so little insulation that the loft was almost unusable – freezing in winter, boiling hot in summer, and extremely draughty – with the rest of the house not much better. The insulation that we have installed, together with many triple-glazed windows and a wood-burning stove, have made the house now very comfortable, and our heating bills have been reduced by nearly two-thirds with the additional help of solar thermal panels on the roof and a new boiler.”
ROOF, WALLS AND FLOORS
The roof was insulated internally, as also the walls of the loft and the (solid) front wall of the house (which faces north; external insulation to the front wall would have been cheaper and less disruptive, but was precluded by the stucco on the outside). Natural woodfibre insulation was used (100mm Pavadentro), which, because it can breathe, avoids problems of condensation; it also has the advantage of absorbing heat, letting it out when the house cools down. Breathability was also enabled by the use of natural lime plaster and breathable paint.
Similar woodfibre bats (Pavaflex) were installed (by ourselves) under the ground floor – these keep out the draughts which had come up through the gaps in the floorboards.
WINDOWS AND DOORS
New triple-glazed French doors in the loft replaced a strip of U-PVC windows whose seal had failed, and a triple-glazed Velux was installed in the front slope of the roof.
External venetian blinds on the south-facing French doors keep the sun off the loft on hot days, helping to keep it cool.
Triple-glazed windows were installed in the front of the house, and similar French doors on the ground floor back.
A well-insulated front door – without a letterbox to banish draughts – replaced a U-PVC door (we now have a mailbox on the front wall).
The old non-condensing boiler was replaced with a Viessmann boiler with external weather compensation system – the latter anticipates how much colder the house is likely to get when the weather outside gets colder (and similarly if the weather outside gets warmer); note that the level of compensation had to be adjusted on our boiler to allow for the high level of insulation in the house, otherwise it overcompensates for cold weather outside by heating the house up too much!
A Clearview wood-burning stove (5kw) in the open-plan ground floor (except hall) heats the whole house on winter evenings (if the doors are left open), so the central heating is turned off (the house benefits in this respect from being centered around the stairwell, without a back extension). The stove is attractive to watch when it is burning, and can be used to boil kettles/saucepans.
Two solar thermal panels on the back slope of the roof (south-facing) heat the water in bright weather.
Six photo voltaic panels (Panasonic, 1.98kWp output) have more recently been installed on the flat dormer roof of the loft, connected to a 7kW capacity LG battery. As we are a relatively low electricity-consumption household, this has meant that we can live very largely on home-produced electricity over the summer months.