23.2 Household Renewable Options

Introduction

Households can play a direct role in the energy transition by generating their own renewable energy or by switching to cleaner options for heating, cooling, and hot water. This chapter focuses on what is specific to the home scale, from installing systems on your property to choosing renewable-based services from outside providers. Concepts such as overall personal footprints or workplace actions are covered in other chapters and are not repeated here.

On-Site Electricity From Solar PV

For most households, solar photovoltaic panels are the most accessible way to produce renewable electricity directly at home. Small systems can power a part of your needs, while larger systems can cover most of your annual electricity use if the roof and local regulations allow it. Panels are usually installed on rooftops, but they can also be placed on carports, pergolas, or ground mounts in a garden.

The main elements of a typical rooftop system are the modules that convert sunlight into direct current, the inverter that converts this into alternating current for home use, mounting structures, and cables and protection devices. In grid connected homes, the system is usually sized to match your daytime use and to send any surplus to the grid if allowed. In off grid or backup focused homes, batteries and charge controllers are added, but detailed battery topics are addressed elsewhere in the course.

The output of a home PV system depends on three factors that you can influence: roof orientation and tilt, shading, and system size. South facing roofs in the northern hemisphere, or north facing in the southern hemisphere, usually provide the highest annual output. A tilt angle roughly similar to the local latitude is often used as a starting point. Avoiding shade from chimneys, trees, and nearby buildings is critical, especially at midday when solar intensity is highest.

A very simple estimate for annual electricity from a solar system is:

$$E_{\text{year}} \approx P_{\text{peak}} \times H_{\text{sun}} \times \eta_{\text{system}}$$

where $E_{\text{year}}$ is yearly energy in kilowatt hours, $P_{\text{peak}}$ is the installed peak power in kilowatts, $H_{\text{sun}}$ is the local yearly full sun hours per kilowatt, and $\eta_{\text{system}}$ is an overall system efficiency factor that accounts for losses.

Household systems can be connected under different arrangements with the grid, such as simple export of surplus, net metering where imports and exports are balanced over a period, or self consumption only. The exact rules are defined by local policy and regulation rather than by the technology itself.

Small Wind and Other Microgeneration

In areas with strong and steady winds, some households consider small wind turbines as an additional source of electricity. These are usually mounted on a tower in an open space, not directly on a roof, because turbulence from buildings and trees reduces performance. For a home turbine to be effective, average wind speeds at hub height must be quite high. Many urban and suburban locations do not meet this condition.

Small wind systems share some features with household solar, such as the need for inverters, controls, protection equipment, and often battery storage for off grid uses. However, they also bring unique considerations that matter especially at household scale. Rotating blades can create noise and visual impacts that affect neighbors, and safety clearances must be respected to avoid danger from blade failures or ice throw in colder climates. Permitting requirements for towers can be stricter than for rooftop solar.

Besides wind, households can use small scale hydro in rare cases where a suitable stream is available on private land, with sufficient year round flow and drop in elevation. Such systems are technically part of hydropower applications and must be carefully managed to avoid damaging the local aquatic environment. In practice, micro hydro at the household level is only viable in particular rural settings.

Renewable Heat for Space Heating

While electricity gets most of the attention, household energy use is often dominated by heating in colder climates. Shifting space heating away from fossil fuel based systems to renewable heat is a powerful household level action, and it involves specific options.

Modern air source or ground source heat pumps can supply space heating using electricity and environmental heat from the air or ground. When the electricity that runs the heat pump comes from renewable sources, the overall space heating can be largely renewable. The details of heat pump technology are covered in other chapters, but from a household perspective, choosing the right size, checking building insulation, and updating radiators or underfloor systems are practical steps that can influence performance.

In some regions, households can connect to district heating networks that are increasingly supplied by renewable sources such as biomass, large heat pumps, solar thermal fields, or waste heat. In such a case, the household renewable option is to choose or support a district provider that is transitioning to renewable heat.

Households in rural areas sometimes rely on modern biomass heating, such as pellet stoves and boilers that burn compressed wood pellets with high efficiency and automated feeding. These are different from traditional open fires and basic stoves, with better control over combustion and reduced emissions when properly installed and maintained. Since biomass sustainability and air quality issues are complex, they are treated in detail elsewhere. At the household level, the key point is that any biomass system should be certified, correctly sized, and used with appropriate fuel quality to minimize smoke and indoor and outdoor pollution.

Renewable Hot Water Options

Domestic hot water is another significant energy use that can be supplied from renewable sources. Two practical options stand out at the household level: solar thermal water heaters and heat pump water heaters.

Solar thermal water heaters use collectors, usually placed on the roof, to warm a fluid that transfers heat to a storage tank. The main household decisions involve collector area, tank size, and whether to use a separate backup heater for periods of low sun. Systems can be thermosiphon units, where water circulates by natural convection with the tank mounted near the collectors, or pumped systems with more flexible layouts. In many climates, a well designed solar water heater can cover a large fraction of annual hot water needs.

Heat pump water heaters use an electrically driven heat pump to lift heat from the surrounding air or ground into the water tank. When powered by renewable electricity, they provide renewable hot water with much lower electricity use than a simple electric resistance heater. From the household perspective, installation location is important for noise, airflow, and protection from freezing, and proper controls help coordinate hot water production with periods of solar PV output if panels are present.

Some households also access renewable hot water through shared systems in apartment blocks or district heating that provide centrally heated water. In those cases, the renewable choice is collective, but residents can support decisions and investments through building associations or local governance.

Household Scale Solar Thermal for Space Heating

In colder regions with clear winter skies, some households use solar thermal not only for hot water but also for space heating. This typically requires larger collector areas and larger storage volumes than water only systems. Floor heating, which runs at lower temperatures, is particularly suitable because solar collectors deliver moderate temperature heat.

At the household level, such systems are often combined with another heat source, such as a biomass boiler or backup electric or gas heating. The solar part covers a share of the total heat demand, while the backup system takes over during long cloudy periods or very cold snaps. The integration details, such as how mixing valves and controls manage temperatures, are part of heating system design and are not treated in depth here. The important point is that households interested in this option must consider both building insulation and collector space, because solar heating is much more effective in well insulated buildings.

Community and Shared Household Renewable Projects

Not every home has a suitable roof, yard, or budget for individual systems. Community level and shared arrangements allow households to benefit from renewable energy even without on site installations.

In many regions, households can subscribe to community solar projects, where a larger off site PV installation sells shares or subscriptions. Participants receive credits on their electricity bills corresponding to a portion of the project output. Some models involve direct ownership shares, while others are subscription services with monthly fees. The technical operation of these projects fits into broader community solar models that are explored elsewhere in the course. For the individual household, the main tasks are to understand the financial terms, contract length, and how bill credits are calculated.

Housing cooperatives and multi apartment buildings sometimes install shared solar PV on the roof or shared solar thermal for hot water. Costs and benefits are allocated among residents by agreement, for example through ownership shares or rent adjustments. These arrangements shift part of the decision making from individual households to building level governance, so residents need to engage in collective discussions about investment, maintenance, and risk sharing.

Some utilities and energy providers offer green tariffs or renewable electricity contracts. While the generators are usually located elsewhere, a household can choose to buy electricity that is matched by renewable generation or covered by renewable energy certificates. The specific functioning of certificates and green tariffs is treated in other chapters. Here it is enough to note that for many households that cannot install on site systems, these products provide a way to support renewable generation and align household electricity purchases with climate goals.

Backup Power and Resilience with Household Renewables

Household renewables can also play a role in improving resilience during grid outages. This aspect is separate from overall emissions reduction, but it can influence how systems are designed and used.

A standard grid tied solar PV system without batteries usually shuts down during outages for safety reasons, so that it does not energize lines while workers are repairing them. However, some inverters support limited backup power if they include special features and wiring. When batteries are added, a home can create a small islanded system during outages, powering selected loads such as lighting, refrigeration, and communications. Detailed microgrid and islanding concepts are covered elsewhere, but households can still decide whether backup capability is a priority and choose system components accordingly.

In off grid homes, such as cabins or rural houses without grid access, household renewable systems are the main source of power. Here, solar PV with batteries is the most common option, sometimes combined with small wind or generators that run on liquid fuels as backup. System design must balance array size, storage capacity, and load management, which is more complex than for typical grid connected homes.

Choosing Between Household Renewable Options

Household renewable options vary widely in cost, complexity, and suitability. A practical starting point is to look at the main categories of household energy use: electricity, space heating and cooling, and hot water. For each category, the household can identify where renewables can be integrated or where fossil systems can be replaced as they reach the end of their life.

In many grid connected homes with usable roof space, rooftop solar PV combined with efficiency improvements is often the first renewable step. For households in colder climates, pairing PV with a heat pump for heating and cooling or with a heat pump water heater can gradually shift most energy use to renewable electricity, especially if the household also chooses a renewable electricity contract for any remaining imports. In rural or specific local contexts, small wind, biomass boilers, or micro hydro can complement these options where appropriate.

Financing and ownership models also matter at household scale. Some homeowners purchase systems outright, while others use leasing, power purchase agreements, or on bill financing provided by utilities or third parties. The details of financing models and their economic implications are developed in other chapters on economics and project development. For the household, the key is to understand contract duration, maintenance responsibilities, and what happens if the property is sold.

Household renewable options are most effective when they are considered together with energy efficiency and conservation. Smaller, better insulated, and more efficient homes need smaller renewable systems to meet their remaining needs. Other parts of this course address efficiency and behavior in detail, but from the perspective of household renewables, improving the building and appliances first can make the renewable transition easier and more affordable.

Practical Steps for Getting Started

Once a household has identified the most promising renewable options, there are several practical steps to move from idea to implementation. First, it is useful to collect basic information about current energy use from bills, including annual electricity consumption in kilowatt hours and fuel use for heating or hot water. This helps size systems and compare technologies.

Second, understanding site conditions, such as roof size and orientation, shading patterns through the day and seasons, local climate, and any restrictions in building codes or heritage rules, is essential. In apartments or rented homes, it is important to clarify whether landlords or building associations allow installations. Where individual systems are not possible, households can focus on community projects or renewable based contracts with suppliers.

Third, households should consult qualified professionals for technical design, safety checks, and regulatory approvals. Electrical and plumbing work must follow local standards and permitting processes, and connection agreements with the grid operator are often required for PV and other generators. Maintenance needs and warranties should be clarified in advance, since domestic systems must operate safely and effectively over many years.

By combining informed choices about technologies, careful planning, and attention to local conditions and rules, households can use a variety of renewable options to reduce reliance on fossil fuels, improve comfort, and contribute to wider energy system changes that are discussed across this course.