Think going green means starting over? Think again.

I recently told historic preservation expert Claire Thielke about my 1921 Houston Heights house and asked what a family like mine could do to green up. Elaborate water systems and replacing the roof with solar panels would be a hard sell.

What I found out was that while there are some seriously progressive green home-builders in town, my house was already a lot greener than I thought.

"Older homes have great bones," Thielke says. They're more than likely built from local materials, from lumber that was cut either onsite or nearby. They've got balloon frames and more time was spent on their joints.

"There was no air conditioning," Thielke says, "people actually had to think about window placement and air flow."

I came away from our conversation with a new respect for my creaky old house (where a marble rolls straight into the corners of my living room) — and with 10 easy tips to make both the house and our energy bill more sustainable.

Pay attention to the sun — East and west-facing windows get the most light. Glazing your windows can prevent temperature loss and reflect some sunlight away from your house. Screens and heavy drapes are also effective.

Install light dimmers — 75-watt traditional light bulbs dimmed by 30 percent for three hours a day can save you 25 percent on your home lighting expenses.

Insulate properly — Seal for air flow around windows and major joint areas. The attic is one of the worst areas for temperature loss. You can tack on insulation plates in the attic to protect against heat loss from the bottom and give your cooling and heating system a break.

Automate your thermostat — Set your thermostat to automatically adjust the temperature when you're not home.

Install ceiling fans — It's another easy way to cut your cooling bill and improve air flow.

Get an energy audit — Even for the most casually environmentally conscious , this more-focused home inspection lets you know where you can minimize your impact, and what appliances are using the most energy. Just remember to balance the tradeoff.

Sure, older appliances tend to use more energy, but where does that castoff microwave go? Right in a landfill.

Don't forget the yard — Orient your planting to take advantage of your home's relationship to the sun. A well-placed tree can easily do as much for your energy bill as those heavy drapes. And the yard itself can be a huge energy suck, reflecting heat off of heavy surfaces like concrete right back onto your house. Crushed gravel and similar materials allow heat to be defused.

Hit Craigslist before Pottery Barn — The concept of embodied energy is an important one. Embodied energy is the energy used to make a product. In basic terms, the longer you use something, the less energy is needed to produce a new product and the more energy valuable the old one is. If you want to prolong the energy of your home, start with the products in it and buy used when you can.

Run appliances on surge protectors — Using a surge protector for your appliances helps offset the energy drainage of vampire power — the power many appliances still use even when they're shut off.

Change your linens — It's not always summer here, believe it or not. Changing your linens from winter to summer changes your perception of indoor temperature and where you need to set your thermostat.

Claire Cormier Thielke studied Urban Planning and Design at Stanford University and has a masters' degree in historic preservation and green retro-fitting.