AP Syllabus focus:
‘Home energy conservation includes adjusting thermostats, reducing heating and cooling demand, conserving water, using energy-efficient appliances, and choosing conservation landscaping.’
Energy conservation at home reduces energy demand, lowers utility costs, and decreases environmental impacts from electricity and fuel use. Practical changes target the biggest household energy uses: space conditioning, hot water, and appliances.
Core idea: use less energy without losing needed services
Home conservation combines behavior changes, efficient technologies, and building/yard design so the home delivers the same comfort and function with fewer energy inputs.
Energy efficiency: Using less energy to provide the same service (for example, the same lighting level or indoor temperature).
Efficiency improvements often reduce pollution and greenhouse gas emissions because less fuel is burned upstream at power plants or in home heating systems.
Adjusting thermostats (heating and cooling setpoints)
Small thermostat changes can produce meaningful savings because space heating and air conditioning are typically the largest home energy uses.
High-utility thermostat practices
Set the thermostat lower in winter and higher in summer when the home is occupied.
Use setbacks while sleeping or away to reduce runtime.
Prefer programmable/smart thermostats to automate schedules and prevent “setpoint creep.”
= electrical energy used, in
= device power demand, in
= operating time, in
This relationship explains why reducing HVAC runtime (time) or choosing higher-efficiency equipment (lower power for the same heating/cooling) cuts total energy use.
Reducing heating and cooling demand (building envelope and habits)
Conservation focuses on reducing unwanted heat transfer and air exchange so the HVAC system does less work.
Diagram of a house highlighting common air-leak locations in the building envelope (attic, walls, floors, and penetrations). The labels make it clear how small gaps can create major infiltration pathways, increasing heating and cooling loads and forcing HVAC systems to run longer. Source
Building-envelope improvements
Insulation in attics/walls/floors to slow conduction.
Air sealing (weatherstripping, caulk) to reduce drafts and infiltration.
High-performance windows (double-pane, low-emissivity coatings) to reduce heat loss/gain.
Shading and window management (blinds/curtains) to limit summer solar heat gain and retain heat in winter.
Everyday practices that reduce loads
Use ceiling fans to improve perceived comfort (allowing higher summer setpoints).
Avoid heating/cooling unused rooms; close doors and manage vents where appropriate.
Maintain HVAC systems (clean filters, serviced ducts) so equipment operates efficiently.
Conserving water to save energy
Water conservation is also energy conservation because energy is required to pump, treat, and heat water.
Set of diagrams showing alternative hot-water distribution system designs (trunk-and-branch, core, and manifold). The visuals connect plumbing layout to wait time, wasted water volume, and the extra energy needed to heat water that never reaches a fixture. Source
Hot-water–focused actions
Take shorter showers; install low-flow showerheads.
Wash clothes with cold water when feasible.
Fix leaks (hot-water leaks waste both water and heating energy).
Set water heater temperature appropriately and consider insulating hot-water pipes to reduce standby losses.
Using energy-efficient appliances and lighting
Appliance choices influence long-term household energy demand, especially for devices that run frequently.
High-impact upgrades and settings
Choose ENERGY STAR–rated (or equivalent high-efficiency) appliances.
Replace incandescent bulbs with LED lighting and turn off lights in unoccupied spaces.
Use appliance “eco” modes and run full loads in dishwashers/laundry to reduce energy per use.
Reduce “phantom” or standby power by unplugging idle chargers/electronics or using smart power strips.
Choosing conservation landscaping
Landscaping can lower heating and cooling demand by changing microclimate around the home.
Landscaping strategies that reduce energy use
Plant deciduous shade trees on the sun-facing side(s) for summer cooling while allowing winter sunlight after leaf drop.
Use windbreaks (shrubs/evergreens) to reduce winter wind exposure and heat loss.
Select native/drought-tolerant plants and mulches to reduce irrigation demand, indirectly saving pumping and treatment energy.
Group plants by water needs (hydrozoning) to avoid overwatering.
FAQ
Many use occupancy sensors, learning algorithms, and outdoor weather data.
They optimise schedules by reducing runtime during low-need periods while maintaining comfort targets.
Common culprits include set-top boxes, game consoles, and older audiovisual equipment.
A plug-in energy meter can reveal continuous watt draw even when devices appear “off.”
Air sealing reduces uncontrolled air exchange (infiltration/exfiltration).
Insulation slows heat transfer through materials. A tight, well-insulated envelope reduces HVAC cycling and improves comfort.
Prioritise deciduous trees to block high summer sun while allowing lower-angle winter sun after leaf drop.
Avoid shading south-facing winter solar gain in colder climates unless overheating is a bigger concern.
Poorly matched fixtures can feel weak if household water pressure is low.
Choose quality, pressure-compensating models and ensure aerators/showerheads are compatible with your plumbing system.
Practice Questions
State two household actions that conserve energy by reducing heating and cooling demand. (2 marks)
Any two valid actions (1 mark each), e.g. improve insulation; seal air leaks/weatherstrip; use shading/curtains appropriately; adjust thermostat setpoints.
Explain how conserving water at home can reduce overall energy use, and describe three specific measures a household could take. (6 marks)
Explains link between water and energy (up to 2 marks):
Energy is used to pump/treat/distribute water (1).
Energy is used to heat domestic hot water; reducing hot water reduces energy demand (1).
Three measures described (up to 3 marks; 1 each):
Low-flow showerhead/shorter showers.
Fix leaks.
Cold-water laundry.
Insulate hot-water pipes or reduce hot-water use in dishwashing.
Clear connection of each measure to reduced energy use (1 mark).
