Energy at Home

Heating, cooling and lighting: where small decisions add up. Covers: The Tap, the Television and You and Climate Control (Energy at Home).

Where small decisions add up

A home does not consume "electricity" in the abstract: it consumes a series of very specific services — keeping the indoor temperature comfortable, heating water, lighting, preserving food, washing, entertainment — and each of those services has its own energy-conversion chain, its own efficiency, and its own room for improvement. Heating and cooling the indoor air is usually, by a wide margin, the largest energy consumer in a typical home; hot water usually comes second; the rest — lighting, appliances, consumer electronics, standby consumption — shares a smaller, though not negligible, fraction of the total. Confusing these relative magnitudes is the most common and most costly mistake when deciding where it is worth investing time, money or attention.

No single decision solves everything

Unlike a power plant or a transmission network, which can be improved with a single large engineering investment, household consumption is built up from dozens of small, scattered decisions: how thick a wall's insulation is, a heat pump's seasonal efficiency, the habit of turning off a screen that is not being used, the reference temperature chosen for the thermostat, the load a washing machine is run with. No single decision on its own transforms a home's energy bill, but the sum of them does, and substantially so. This block walks through those decisions in the order it makes sense to address them: first the building envelope and the large climate-control systems, where most of the real consumption is concentrated, and then everyday habits and small scattered loads, which matter, but should not overshadow the former.