Green building has become a poster child for everything from solar panels to bamboo flooring. While all aspects are of green building are important, the first step towards a green home is to get the core systems working properly.

At Sustainable Spaces, when we work with homeowners to develop a roadmap for retrofitting their houses, we emphasize getting the basics, or the infrastructure, done right. It might not be sexy, but it is the core of the house. After looking at the basics, we focus on major systems, such as heating systems, water heating, ventilation, and air-conditioning. Once the house is operating efficiently, with good air quality and comfort, then we look at properly sized renewable energy systems such as solar and wind. These systems will be much smaller (and more affordable) because the house now uses much less energy.

But what can a homeowner do right now that will have an impact on their energy load, without involving a major home remodel? Here’s my top five list of improvements anyone can make to get on the path of energy efficiency, at a reasonable cost. Keep in mind that it’s important to accomplish the to-do list in the order they are presented below. For instance, there is no point in insulating before you’ve reduced air leakage.

1) Get a home energy audit – Start by evaluating your entire house as a system. It’s not about products; it’s about results. A building science-based audit will help you create a plan to fix your home based on what will have the maximum results. And PG&E will even help underwrite this audit! See EnergyStar.gov for more info

2) Reduce air leakage – Heated or air-conditioned air leaks out through gaps, cracks and holes in your home’s walls and ceilings and means your energy dollars are floating away. Sealing these penetrations is the most cost effective way to save energy. Most leaks are between your house and your attic. Read a Fine Homebuilding article on the topic here.

3) Seal your ducts – In California, the average duct systems (the tubes that move heat from your furnace to your house), has 30% leakage. When you figure that 40% to 50% of your home’s energy goes through this system, you can see that it has a huge impact on your bill. This system is also responsible for your home’s comfort and indoor air quality. Leaky ducts bring in dirty air from all the worse places to replace the air that escapes. Poor design and leaks mean that there is imbalanced distribution that results in cold and hot rooms, and general discomfort. When sealing duct work, use mastic not duct tape.

4) Add insulation – Adding insulation should happen after you air seal (or air sealing becomes very hard to do later). Generally adding insulation to the attic is the easiest and has the fastest return. You should have 10 inches of insulation or R-30+. We recommend using blow-in cellulose (recycled newspapers). If you want to do it yourself and use batts, try to get blue jean batts – but remember that you must install the insulation very carefully, as most insulation only performs at 50% of its rated value due to air gaps, compressions, and other installation defects. When adding a layer of batts to an attic, lay it perpendicular to the first layer to help reduce air gaps.

5) Replace light bulbs / appliances / plug-loads – Compact Florescent Bulbs (CFLs) use 25% the energy for the same amount of light. Replacing a 15 year old refrigerator with an energy star model can cut your bill by 60%. That’s a pretty substantial amount in two steps. Plug loads can be negated with a power strip plugged into a switchable wall outlet.

Not everyone can make their home 100% green and zero energy in the ï¬rst-pass, but by creating a comprehensive plan homeowners can begin the path towards sustainability and see real results on almost any budget.

And remember, a green house does not necessarily mean it is full of fancy new technology. There’s usually 30% to 40% waste just in these fundamental issues that don’t need fancy solutions to resolve them!

–Matt Golden is president of Sustainable Spaces, a home energy performance company in San Francisco, Calif