What's the best combined heating and AC unit to get for a 1200 sq ft, single story, 1920s Spanish house in LA?

Asked by Karin
Los Angeles, CA


Ted Kidd

Answered by Ted Kidd

Rochester, NY

Ted Kidd Energy Guru

November 23, 2010

Every house is so different, your best solution will need to be tailored to meet your home and your budget.

The best way to do this properly and avoid expensive mistakes is to have an energy auditor assess your home, including a blower door test and manual J load calculation. This will define your home's current conditions, and may uncover hidden opportunities to increase comfort and reduce energy bills.

A lot of the tenets of building science are completely counterintuitive. Often people's erroneous preconceptions take them down the path of bad design. Take these two proven building science concepts, for example:

  • Smaller equipment is better. By installing the smallest equipment possible, you will get much more even temperatures throughout your home. Also, equipment and airflow noise is dramatically reduced with smaller equipment.
  • Longer run times are better than short. Equipment takes a while to reach optimum efficiency, so short cycles may mean the equipment NEVER reaches optimum efficiency.

For most people, these two concepts cause eyes to widen. I could go on for days listing misguided assumptions and preconceptions that I have had turned on their heads.

You asked about heating-cooling equipment for your home.

  • Based upon the size of your home and its location, I suspect some type of small hybrid system or mini-split heat pump will be options you should explore.
  • If you get a traditional system, I would strongly encourage multi-stage equipment, as I suspect you will find they don't make single-stage small enough to properly match the load of your home, even in the very coldest weather you experience.


For more information:

Read Rick Goyette's Q&A "Should I go with an air source heat pump or electric radiant floor heat?"

Also, read Randy Potter's Q&A "I can't afford geothermal. Is an air-to-air heat pump my best option for heating?"

Tagged In: heating cooling

Do you have a question about greening your home? GreenHomeGuide invites you to Ask A Pro. Let our network of experienced green building professionals – architects, designers, contractors, electricians, energy experts, landscapers, tile & stone specialists, and more – help you find the right solution.