Clean Energy and Home Efficiency: The Complete Topic Guide

Start here. Solar is one part of a home energy system, and it is rarely the first part worth buying. This is the map to our 18 guides on efficiency, heat, water and the wider clean energy picture. The sequence that saves the most money is efficiency, then electrification, then generation — start with the home energy audit.

On this page

• Efficiency comes first
• Which guide fits you
• Heat and hot water
• Beyond the house
• Getting started and policy
• AI and markets
• FAQ

Efficiency comes first

Every kilowatt-hour you stop wasting is one you never have to generate. These four return more per dollar than panels in most older homes.

• Home energy audit — what a blower door test and thermal camera actually find
• Attic insulation — the cheapest upgrade in most houses, and why air sealing comes first
• Smart thermostats — an honest look at the savings, including the heat pump setback trap
• Smart energy systems — monitoring, automation and load scheduling
• Next-generation efficiency — where building efficiency is heading

Which guide fits you

Heat and hot water

Heating is usually the largest energy load in a home, and it is where solar thermal still competes with photovoltaics.

• Solar water heaters — types, savings, and an honest comparison against PV plus a heat pump
• Solar pool heaters — the fastest-paying solar system, and why a cover comes first
• Geothermal vs solar — why these are complements rather than competitors

Beyond the house

• Greenhouse solar power — where to put panels without starving the crop
• Solar desalination — turning sunlight into fresh water

Getting started and policy

• Getting started — the practical first steps for a household
• Clean energy for homes — the full menu of options
• Policy changes — what shifted this year and what it means
• Technology trends — the developments actually reaching market
• The clean energy future — the longer-range outlook

AI and markets

• AI in energy management — forecasting, scheduling and fault detection
• AI in solar technology — where machine learning is genuinely helping
• Clean energy sector research — educational sector background, not investment advice

FAQ

Should I insulate before installing solar?
Yes. Reducing consumption first lets you size a smaller, cheaper array against real post-retrofit usage.

Is solar thermal better than photovoltaics for hot water?
Per square metre it captures more energy. Overall, PV plus a heat pump water heater is often cheaper to install and easier to maintain.

Do smart thermostats really save money?
Sometimes. The savings come from not conditioning an empty house, so they are largest if you currently hold one temperature all day.

Is geothermal worth it?
In severe climates with a long occupancy horizon, often yes. In mild climates a modern air-source heat pump usually wins on total cost.

Can I put solar on a greenhouse roof?
You can, but opaque panels compete with the crop for light. The north slope, an adjacent building or a ground array are usually better.

What is the right order of upgrades?
Air sealing and insulation, then electrified heating and hot water, then solar sized against the new consumption.

More

Browse the full Clean Energy & Future Tech category, or see the costs and incentives guide.

Efficiency guidance is published by the U.S. Department of Energy and ENERGY STAR.