Before you do anything new...look at what is already there. 

1. Do the existing windows allow drafts?  Upgrade existing windows first before considering new windows.  I don't think the payback is that great over existing windows that are properly maintained. 

2. Is the header serviced annually?  Change the filter monthly (there are so cheap), check all the ducts for breaks and tape them up.  Walk around the house when the heater(s) are on and check the temperatur in each room.  When you have done your homework then have a profeswsional come in.

3. Seal around the ceiling can lights on the second floor that are allowing heater air into the attic. 

4. Replace the seal around all your exterior doors.  This is really the case on the door from the garage to the house. 

Start there \Philp Anderson HDR Remodeling Berkeley CA

With current financing options that are available, the best return-on-investment is to go solar!  It may seem expensive to install a solar panel system, but with current financing options such as $0/down home-equity loans, you'll see immediate cash flow savings!

Solare Energy has been serving San Diego for 25 years and provides our customers with a free energy audit and rate analysis before designing a solar panel system for their homes.  This allows us to accurately size the system to your energy consumption needs and get you the best value for your investment.

Learn more at www.SolareEnergy.com or call 858-547-4300 for San Diego area solar installations.

Rob Shaw
Marketing Manager
Solare Energy, Inc.
San Diego, CA

Many great answers here regarding insulation and air sealing.  If you have a pool, also look into upgrading your pump to a variable speed pump.  They run at lower RPM for filtering than they do for vacuuming.  This can be a significant saver in energy costs... and as always, GO SOLAR!

Solare Energy has been serving San Diego for 25 years and provides our customers with a free energy audit and rate analysis before designing a solar panel system for their homes.  This allows us to accurately size the system to your energy consumption needs and get you the best value for your investment.

Learn more at www.SolareEnergy.com or call 858-547-4300 for San Diego area solar installations.

Rob Shaw
Marketing Manager
Solare Energy, Inc.
San Diego, CA

Alex,

Solar is one of the best home improvement opportunities available to homeowners today.  The return-on-investment is over 100% (unlike most of home improvements).  See immediate cash flow savings by "zeroing-out" your energy bill.  The increase in value and decrease in time-on-market will also help when it comes time to sell.

There is still a 30% federal tax credit available, as well as other incentives depending on the state where you live.  Financing options range from cash purchase to lease/PPA.  You'll see the best rate of return on a cash purchase, though any option is usually better than the price you pay for utilities.

Solare Energy has been serving San Diego for 25 years and provides our customers with a free energy audit and rate analysis before designing a solar panel system for their homes.  This allows us to accurately size the system to your energy consumption needs and get you the best value for your investment.

Learn more at www.SolareEnergy.com or call 858-547-4300 for San Diego area solar installations.

Rob Shaw
Marketing Manager
Solare Energy, Inc.
San Diego, CA

Definitely replace your air filters every single month as this is a big contributor to a home's energy efficiency when it comes to HVAC

Solar Panels are increasing in energy generation and energy storage is getting better and better.  You definitely need to make sure that your dwelling is positioned on the property to maximize benefits.  While it is way down the road, make sure to investigate the implications of what happens when the day comes to replace your shingles.  I would make sure you also have adequate insurance in the event the panels are damaged by hail, trees etc. and that you have a comprehensive maintenance program in place should you elect to have panels installed.  You may want to check with your local building code authority and see if you are able to have solar panels on your property other than on the roof if you have enough space.  Just like the VCR, solar panels are coming down in cost and going up in efficiency, so you may want to wait.  If you could have many less panels in the near future, that produce more output, that may be the best choice. Here is a link of many residential applications https://images.search.yahoo.com/search/images;_ylt=A0LEVzpL309ThhkA45xXNyoA;_ylu=X3oDMTB0YXQwZXBpBHNlYwNzYwRjb2xvA2JmMQR2dGlkA1ZJUDQxNl8x?_adv_prop=image&fr=yfp-t-745-s&sz=all&va=solar+panels+homes

Check seals on doors & windows.  Replace single pane windows with newer products.  Check the attic for insulation.  Loose fill, blown in insulation is the best.  Make sure to seal any spots where air is escaping INTO the attic first.  Also make sure your attic has both adequate intake AND exhaust ventilation.  Make sure not to clog the airflow from the soffit area and the attic space by using Baffles as seen in the picture.  Check out YouTube for other great suggestions. 

If anyone tells you that you can save "X" with windows, throw them out of the home. Will you save something, yes. Is is impossible to tell what that something will be without a laboratory environment, yes as well.

When looking at window performance, it is imperative that you compare both U-Factors and Air Infiltration rates. A window that is tighter will be more efficient over its lifespan in the home.

WoW Home Solutions

We suggest Simonton Vinyl Replacement windows to all our customers. They are very energy efficient and work flawlessly. I will show a customer a lot of the times how I can open the window with ease with my pinky finger. It's hard to say how much you will save on your energy bill. There are a lot of factors involved. If you currently have a well insulated home and low energy bill you probably won't save that much. If your home isn't that well insulated and large energy bills it will show up more there. I use the example of my grandfather alot. He replaced his windows with Simonton about 10-15 years ago. They have a small 3 bedroom ranch and were having utility bills of $3-400 a month. They replaced the windows and the bill came down to $100 a month. If you are having a hard time keeping your rooms cool in the summer and warm in the winter, you will see a drastic difference in your comfort level along with the power bill. Another reason we offer Simonton is the affordability. We typically install a 5050 replacement window turnkey around $400 per window. Of course there are reasons this can go up, but typical install is on average this price. I would suggest going to simonton.com and searching for an experienced installer in your area. Hope this helps! Good luck with your search. 

I say insulation should be at the top of your list. I would also take a look at your water pumps.

Here's a few of the items we actuallyp ersonally suggest when going green: http://xtremegreenhomes.com/green_options.php.

Alex,  

Solar panels are a great long term solution for energy savings. The average time frame for recovering the initial cost of the panels and installation is about 5 years, so if you are planning on living in the home for longer than 5 years, you will begin to see a return on your investment around year 6 and beyond. Also a big bonus is that tax credits are available to homeowners on both the state and federal level for solar currently!

Hope this helps! Good luck with your new home =)

Eric Consuegra, Arocon Roofing and Construction

We have written on good bit on this subject: Please take a look at these blogs we wrote!

http://blog.akatlanta.com/2010/11/10-mistakes-not-to-make-when-heating.html

http://blog.akatlanta.com/2010/11/7-winterization-tips-to-keep-your-money.html

+1

If you can amortize it into the long term loan on the home, it is a 100% no brainer.

Yes!!

Air sealing and insulation are the two biggest things you can do to globally improve the efficiency of the home. 

There are several articles on this application and I have yet to be in a home that didn't need it. 

Tightening up the envelope across the attic surface will lessen air infiltration at all the other areas of the home.