Grevillea House 2023

House Notes – Grevillea House

We aimed to build a comfortable home with a touch of luxury which prioritised function over form. A forever home which is very low maintenance and will be suitable for us as we age or have mobility issues. A home which does not need large inputs of external services such as electricity gas and water.
We designed the home ourselves to suit the land making best use of the small block and the unrestricted Northern access.
Features: Central Rammed Earth Wall (REW) completely within the insulated envelope which provides valuable thermal mass in addition to the concrete slab.
Insulation: R5.0 ceiling plus R1.3 roof blanket. Walls R2.5 batts plus 2 layers of RFL.

A sunroom on the NorthWest corner has a large Nth window and an Eastern window. It is well insulated but built with no slab and a low thermal mass. This room is not artificially heated or cooled but is able to be used most days of the year. On sunny winter days it is a comfy retreat and helps to heat the home. On cold nights it is isolated from the main home with a double glazed sliding door and pelmeted curtains.

An evacuated tube HWS provides ample hot water most of the year and rarely needs boosting. All hot water pipes are insulated. The tank is located inside in a laundry cupboard minimising heat loss. An on demand return system on all hot taps sends the initial cold water in the hot water pipes back to the rainwater tank, saving valuable water.
Heating and cooling provided by a single 6kW Daiki split system. Heating is only needed after several cold cloudy days in the winter months when the inside temperature falls to 18deg. The home maintains stable temperatures at all times and with no overnight heating will only drop 1 -2deg overnight in winter. This is due to the thermal mass of the REW, the insulation and the air tightness of the home.

Cooling is aided by DC ceiling fans with the airconditioner used those few occasions when the home reaches 26deg inside.
6.6kW of grid connected solar was installed while the house was still under construction and provides a credit every month of the year.
Electricity use including self consumed solar averages 5.5kWh per day over the year and an average of 24kWh per day is fed back into the grid.
Cooking is by an induction cooktop and an electric oven, no gas is connected to the home

Windows are double glazed aluminium of modest size with 3 large windows on the North 2 modest sized windows on the Sth and total of 4 small windows on the West and East. A ShadeForm retractable awning shades the Living room Nth window and Sunroom East window which were built without eaves.

Water: A 22000 litre concrete tank below the garage provides all water to the home and small garden via a pressure pump. Mains water is available but has not been needed over two summers. The water is screened as it enters the tank and no filtering to the house is required.

The garage is a separate building from the house to prevent thermal bridging to the home and to avoid compromising indoor air quality.

Extra features: ducted vacuuming (better air quality). Electric curtains. Upstairs storage room or office with easy access to the lighted ceiling via an insulated door.