Heating and cooling is usually one of the largest parts of a home’s energy bill, so small changes in how the system runs add up. The twelve steps below run from free habits to improvements that cost money but pay back over time. Start at the top: the free ones cost nothing to try.
Free changes
1. Adjust the thermostat
Every degree matters. Set the heat a couple of degrees lower in winter and the cooling a couple of degrees higher in summer, and the system simply runs less. Change one setting at a time and live with it for a few days before deciding it is too cold or too warm.
2. Use fans
A ceiling fan’s breeze makes a room feel cooler, so you can set the AC a few degrees higher without feeling warmer. Fans cool people, not rooms, so turn them off when you leave. In summer the blades should push air down, which on most fans means turning counterclockwise as you look up; in winter, a slow reverse setting moves warm air off the ceiling without a draft.
3. Close blinds
Window coverings block solar heat gain. On warm days, close them on the windows that get direct sun during the hottest hours, usually the south- and west-facing ones in the afternoon. In winter, do the opposite: open them on sunny days to let the warmth in and close them at night.
4. Seal obvious leaks
Feel for drafts around doors and windows on a windy day. Weatherstripping and door sweeps are cheap and effective, and so is sealing gaps where pipes and cables pass through outside walls.
5. Don’t block vents
Make sure furniture, rugs and curtains don’t cover supply registers or return grilles. The return matters most: a blocked return starves the whole system of air. Closing supply vents in unused rooms rarely saves anything, because it raises the pressure in the ducts and pushes more air out through any leaks. If some rooms are always too hot or too cold, air balancing fixes the cause instead.
Low-cost improvements
6. Change filters regularly
A dirty filter makes your system work harder and run longer for the same comfort. It is the simplest maintenance there is and one of the most effective. Check the filter monthly and replace it when it looks gray, even if the box says it has time left. Use the size and type your system was designed for, because a very restrictive filter can choke the airflow on some systems.
7. Program your thermostat
Set the temperature back when you are asleep or away. If you don’t have a programmable thermostat, a basic one costs $25–50. With a furnace, a deeper setback is fine. With a heat pump, keep the setback moderate or use a thermostat set up for heat pumps, because a large jump back up can bring on the backup electric heat, which costs much more to run than the heat pump itself. Thermostat service can set up or replace a thermostat that does not suit your system.
8. Seal accessible duct leaks
If you can reach ductwork in an attic, crawlspace or garage, seal visible gaps and loose joints with mastic or metal foil tape, not regular cloth duct tape, which dries out and lets go. Supply leaks lose air you have already paid to heat or cool; return leaks pull in hot attic air or dusty crawlspace air. Do not tape or seal the furnace vent pipe: it carries exhaust and is not a duct. In an attic, step only on the framing.
9. Add attic insulation
If you can see the tops of the ceiling joists in your attic, you probably need more insulation. It keeps heat in during winter and out in summer, and it makes every other step on this list work better. Keep insulation clear of the furnace or water heater vent and of any recessed lights not rated for contact with insulation.
Investment improvements
10. Upgrade to a smart thermostat
If you’ll use the features, a smart thermostat can follow or learn your schedule, adjust when nobody is home and show your usage, which helps you spot waste. If you already keep a sensible schedule on a basic programmable model, the extra savings are smaller. Before buying, check that it supports your equipment, especially a heat pump with backup heat or a two-stage system.
11. Consider duct sealing
Many ducts leak at joints and connections you cannot see or reach. Professional duct sealing finds and closes those leaks, and it makes the biggest difference when the ducts are leaky and run through a hot attic. A ductwork repair visit shows whether sealing is worth it in your home.
12. Schedule maintenance
A well-maintained system runs more efficiently. A yearly tune-up checks the airflow, the coils and the electrical parts, and on cooling systems the refrigerant side, so a struggling part gets caught early instead of running up the bill for months. See HVAC maintenance.
What about replacing equipment?
If your system is 15 or more years old and inefficient, replacement might pay for itself in energy savings, especially when it also needs a major repair. Modern systems are significantly more efficient than older models. Whether the savings cover the cost depends on how many hours you heat and cool. The guide to efficiency ratings shows how to work that out, and how long an HVAC system lasts helps you judge how much life is left in yours.
Lowering bills in a Hayward home
A few points specific to the local climate and housing:
- Heating is often the bigger bill. With winter nights in the 40s and mild summers, most Hayward homes heat on more days than they cool. Setbacks, weatherstripping and attic insulation pay off mostly in winter.
- Use cool evenings. On many summer days the air outside cools off by evening. Open windows when it is cooler outside than in and close them in the morning, rather than running the AC into the night. If your electricity plan charges more at certain hours, cool the house before those hours start.
- Hill homes. Homes in the Hayward Hills are cooler and windier at night, so drafts cost more there and air sealing is worth the effort.
- Attic and slab ducts. Many flatland homes sit on slabs, with ducts in the attic or, in some older homes, in the slab. Attic ducts sit in the hottest part of the house in summer, so leaks and torn insulation there waste energy. Slab ducts cannot be sealed by hand, so if floor registers blow weakly or smell damp, have them inspected.