Aggregate consumption typically exceeds 60 per cent of GDP and should be pivotal in central bank policy models. Most have adopted semi-structural macro-models, yet, predominantly, consumption is inadequately specified, based on the simple textbook permanent income form. This paper uses a systems approach to estimate new equations for South African consumption, house prices, mortgage and non-mortgage debt, and income forecasting (to capture income expectations). A credit-augmented consumption function introduces a greater role for uncertainty, varies the spendability of different components of wealth, and includes a key role for credit conditions. The estimated equations provide new insights into the multiple monetary transmission mechanisms, from policy interest rates and credit conditions to aggregate demand, including via non-homogeneous household balance sheet items on consumption. Credit conditions for mortgages and for other debt move quite differently from each other, with implications for consumer spending. Non-mortgage debt covers a larger fraction of total household debt than in advanced market economies, affecting household financial vulnerability. Housing market participants tend to extrapolate recent changes in house prices in forming expectations of capital gains, so positive shocks to housing demand can feed back positively onto house prices and consumption and extend boom conditions. House prices and debt can overshoot relative to their fundamentals, with risks to financial stability. Our new findings should benefit future policy modelling in South Africa.