Summer Cooling Costs, Under Control

Summer cooling costs stay under control when the air conditioning is the last layer, not the first. Keep heat out with shading on sun-struck windows, move air with fans so a warmer setting still feels comfortable, use cooler night air where your climate and security allow, and then run the cooling at the warmest setting the household genuinely finds comfortable. The Department of Energy's cooling guidance works in that same order, because every degree of heat kept out is a degree the system never has to remove. Do the sunny-afternoon walk first, and let it direct the work inside the energy bills system, alongside the summer half of the thermostat schedule.

Sun through glass heats a room like a greenhouse, and the cheapest cooling is the heat that never enters. Outside shading works best where it is practical, since it stops the sun before the glass, and inside, closing curtains or blinds on the sunny side during the hottest hours makes a felt difference even if it is less complete. Follow the sun around your own house: east rooms heat in the morning, west rooms take the punishing late afternoon load, and those west windows are usually the first place shading earns its keep. Trees, awnings and shutters are planned projects for some homes; the household version for this summer is disciplined curtain timing, and it costs nothing beyond remembering, which a household routine or a note by the light switch can carry.

Fans cool people, not rooms, and used with that fact in mind they let the cooling setting rise while comfort stays. Moving air on skin feels several degrees cooler, which is why a ceiling or portable fan in an occupied room is such good value and why a fan running in an empty room is pure waste, a smaller cousin of the heating-empty-rooms problem. At night, where outdoor air is cooler than indoor and windows can be opened safely and securely, whole-house airing before bed can flush the day's heat from the building's fabric, especially in homes that hold heat. In humid climates the balance differs, and the Energy Saver cooling guidance discusses humidity plainly; sticky nights may need the cooling's drying effect more than they need open windows.

Set cooling at the warmest comfortable point and resist the urge to blast a lower temperature to cool faster; most systems cool at one speed, so an extreme setting only overshoots and costs more. Keep the system able to breathe: filters cleaned or replaced as the maker instructs, outdoor units clear of plants and debris, indoor vents unblocked, and condensate drains checked so they do not back up in the season's first heatwave. A system serviced on schedule, like the heating in the heating guide, runs closer to its designed efficiency and is less likely to fail on the hottest weekend. Close doors and vents thoughtfully to unused rooms only where your system's guidance allows, since some systems need their designed airflow to work properly.

Work with the day's rhythm. Pre-cool a little in the morning when outside air is cooler and the system works more easily, rather than asking it to rescue an overheated house at the peak of the afternoon, which is also when time-of-use tariffs, covered in comparing energy plans, often charge most. Move heat-producing jobs, such as oven cooking, laundry drying and dishwashing, toward the cooler ends of the day where the household's life allows, so the cooling is not fighting the kitchen. Dress, bedding and drinks do real work too: light bedding and a cool shower before bed settle sleep at settings that would feel warm under a winter duvet, and comfortable sleepers are what make a warmer night setting stick for the whole season.

Layer the defences and summer stops being the season the bill fights back. Shade the west glass, run fans where people actually sit and sleep, air the house on cool nights, and let the cooling hold a sensible setting without heroics. Walk the house this sunny afternoon, note the rooms that heat first, and fix their shading before anything else. By the first hot week the system will already be in place, and the house can simply be pleasant while the meter turns at a pace you chose.