Now the external walls are complete, the sunspaces and porches can be added to the houses.
The sunspaces to the rear are one and a half storeys high, with flat roofs containing two Velux roof lights, one opening and one fixed. The sunspaces are thermally separated from the main house, i.e. there are external quality triple glazed windows and doors between the house (kitchen/diner) and the sunspace.
The sunspace will harvest passive solar energy, and when the sunspace is warmer than the house, and the tenant wants to heat the house up, the windows and doors can be opened to the house and this heat will then transfer in and get absorbed into the mass of the floor and walls; it will then get given up by the mass when the air temperature cools. We are also planning to have this harvesting automated by a modification to the mechanical ventilation and heat recovery unit, such that it will take its air supply from the sunspace instead of outside, when the sunspace is warmer than the house, and the air temperature inside the house is below a pre-defined minimum.
The sunspaces also include a downstairs bathroom, with a shower, hand basin and toilet, which adds lifetime homes benefit to the houses.
The porches help to separate the internal environment from the outside; they effectively act as an airlock to the house. In winter only one door should be open at any one time, this will help reduce heat loss from the house, and thereby help to keep them warm.