Start with where the waste is
Before buying anything, it helps to know where your household actually uses energy and water. Heating and cooling are commonly the largest share of home energy use, with water heating, appliances and lighting following. The proportions differ a lot by climate, home size and habits, so your own bills are a better guide than any general rule.
A smart device only helps if it targets a real source of waste. A gadget that saves a tiny amount in a category you barely use is unlikely to be worthwhile, however clever it is.
Categories worth considering
Thermostats and zone control
Heating and cooling controls can avoid warming or cooling an empty house, and can follow different schedules for different times. Whether they save much depends on your system and on how you used it before. The specifics are covered in the article on smart thermostats.
Energy monitors and smart plugs
Plugs with power measurement and whole-home monitors show what is using electricity. The main benefit is information: learning that an old freezer or a forgotten device draws more than expected can prompt a useful change. The monitor itself does not save energy; what you do with the knowledge does.
Smart lighting and sensors
LED lighting already uses little power, so the added saving from automation is modest. It mainly comes from lights that switch off when no one is in the room. Options and trade-offs appear in the guide to smart lighting.
Leak and flow detectors
Water sensors placed near a water heater, washing machine or sink can warn you of a leak early, which prevents waste and damage. Some systems monitor water flow at the main line and can flag unusual use. For many households this is one of the more clearly useful categories, because the cost of an unnoticed leak can be high.
Smart irrigation
Controllers that adjust watering according to weather forecasts or soil moisture can reduce overwatering. Their usefulness depends on your garden and local rainfall. Sensible manual scheduling is sometimes just as effective.
Smart power strips and scheduling
Many electronics draw a small amount of power while idle. Switching off clusters of devices, such as an entertainment setup, can trim that standby usage. The amounts are typically small per device, so look at the labels or measure with a monitor before assuming a big impact.
Utility-linked tools
Some utilities provide meters and time-based pricing. If yours does, understanding how smart meters work may let you move heavy use, like laundry, to cheaper periods. Larger investments, such as home solar and home batteries, are big decisions in their own right and need separate research.
How to judge whether a device pays off
A simple payback estimate helps keep marketing in perspective. The formula is:
payback time = purchase and installation cost ÷ expected yearly saving
Here is a hypothetical example, with made-up numbers. Suppose a device costs 120 and you estimate it will save 30 per year. The payback time is 120 ÷ 30 = 4 years. If you believe it will last about 8 years, it is likely to be worthwhile; if it will last only 3, it will not recover its cost.
The tricky part is the yearly saving, which is an estimate. Be skeptical of any precise percentage a maker quotes. Savings depend on your starting habits, climate and home. If you already turn the heating down at night, a device that does it for you saves less than one that fixes a habit you did not have.
Also count hidden costs:
- the electricity the device itself uses;
- subscription fees for apps or services;
- installation, which may require a professional;
- the replacement cycle, since electronics have limited lifespans, a theme in the article on device lifespan.
Sustainability is more than running costs
A device has an environmental footprint of its own: materials, manufacturing, shipping and eventual disposal. Replacing a working appliance purely to get a smart version can easily cost more resources than it ever saves. Often the more sustainable choice is to use what you have, repair it, and upgrade when it fails. Guidance on disposal is in the piece on e-waste recycling, and the wider picture of green technology is introduced in the overview of clean energy tech.
Questions to ask before buying
- What specific waste does this target in my home?
- Can I measure my current usage first, so I can compare afterward?
- Does it work offline, or will it stop working if the company’s service ends?
- Does it have a manual fallback?
- How long will it receive updates?
- Is it cheaper to fix the underlying issue, such as insulation, draughts, an old appliance or a dripping tap?
That last question matters. Low-tech improvements, such as sealing gaps, adding insulation or fixing a dripping fixture, often beat gadgets on both cost and reliability.
A modest approach
Pick one area where your bills are highest. Measure for a month, add one device, then measure again. If the change is visible, consider the next step. If not, you have learned something at a modest cost. The aim is to reduce waste, not to collect gadgets, and every connected device you add brings small ongoing costs in updates, data and attention, as discussed in the article on the connected home. For other categories that fit together with these devices, see the overview of smart home devices.