Warmth and comfort not optional Start by calculating how much energy your home is consuming and what you can save by changing your habits and retrofitting your home. Online aids, like the Home Energy Saver in the US (hes.lbl.gov) or the Energy Star web site or Canada’s Natural Resources home heating calculator (www.canren.gc.ca) are invaluable.

The next step is to calculate the return on investment of generating your own energy, beginning with the simplest technologies and those that give the biggest immediate bang for the buck.

Remember that once you opt for generating your own energy, you’ll need an energy audit to qualify for federal grants – such as this one in the US and EcoENERGY in Canada (and matching provincial grants); your system supplier will provide audit and grant details.

A DRAIN WATER HEAT RECOVERY SYSTEM

Like RenewABILITY Energy Inc.’s Power-Pipe (www.renewability.com), it uses heat from shower, dishwasher and other household waste water to warm cold water before it enters your hot water heater. Hot waste water passes down an interior copper pipe around which cold water tubing is wrapped, warming the fresh water to roughly 25 C from 10 C. There is no contact between waste and fresh water.

Installed cost: $600 to $1,200

Approximate savings: $200 a year

Government rebates: Up to $260

Sources: Home Depot (www.homedepot.com or .ca) for DIYs.

A SOLAR HOT AIR SYSTEM

It consists of wall-mounted solar panels that warm the cooler air from the floor level of your house and return it via a vent mounted a couple of feet below the ceiling. Thermostat-controlled systems, like SolarSheet, use a solar-powered fan to move the air through the panels.

Installed cost: from $2,500

Approximate savings: Up to 15 per cent of annual heating costs

Government rebates: None

SOLAR HOT WATER SYSTEM

Increasingly popular, it consists of solar panels or tubes, usually mounted on the roof, a pump, a heat exchanger and a holding tank. The system pumps a liquid, such as glycol, through a closed loop to the panels or tubes, where it is heated by the sun’s energy, before returning to the basement where it transfers its heat to household water. Popular systems include EnerWorks. Solar heating is especially well suited to swimming pools.

Installed cost: from $6,000

Approximate savings: Up to 60 per cent of annual hot water heating costs.

Government rebates: $1,300 plus

WINDMILLS

Suitable for rural properties, they are great in high-wind areas. They supply power, via an inverter, to a battery bank that then feeds the household energy needs. Windmills can be a supplemental energy source or part of a varied off-grid strategy.

Installed cost: $15,000 plus

Approximate savings: Up to 30 per cent of household electricity; payback is a relatively long 12 to 15 years.

Government rebates: None

SOLAR ELECTRICITY GENERATION

It is, for now, within reach of only the well-heeled. Full-scale systems are very expensive while smaller ones, like windmills, usually require backup energy sources. They are, however, ideal for isolated sites where energy needs are minimal and hydro hookup prohibitively expensive.

Installed cost: $35,000 plus

Approximate savings: As much as 100 per cent

Government rebates: None