Looking for an energy auditor in Foster City, CA? Describe your project once and up to three certified energy auditors who work in Foster City and San Mateo County get back to you with a quote. It's free and there is no obligation.
Foster City is home to about 32,657 people (2024 Census Bureau estimate), a shrinking community (−3.4% since 2020). With 8,623 people per sq mi, it is a densely built-up area. Older homes and long heating or cooling seasons make energy audits worthwhile here.
Foster City at a glance
- Population (Census Bureau estimate, 2024)
- 32,657 (−3.4% since 2020)
- Rank in California
- 229th of 482 cities and towns
- Land area
- 3.8 sq mi
- Population density
- 8,623 people per sq mi (densely built-up)
- Type
- City (Foster City city)
- Main county
- San Mateo County
What to check before hiring in Foster City
- Certification: choose a RESNET or BPI certified professional.
- Rebates: in California, check your utility's programs before booking: some require their own approved auditors.
- Test-in, test-out: a blower door test before and after upgrades shows the result.
- Price drivers: home size, tests included and report detail.
Useful official resources
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ENERGY STAR
Energy efficiency guidance for homes.
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RESNET
Find a certified HERS rater.
Services available in Foster City
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Home energy audit
Whole-home assessment with blower door test and infrared scan, with a prioritized list of upgrades.
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HERS rating
HERS Index rating of a new or existing home by a RESNET-certified rater, for code compliance or programs.
Frequently asked questions in Foster City
How much does an energy audit cost in Foster City, CA?
It depends on the home and the tests. Describe your home: auditors who serve Foster City reply with a quote.
How long does it take?
Usually two to four hours on site.
Will the auditor sell me upgrades?
Some do; an independent auditor gives a neutral list.
Which certified energy auditors will contact me?
Up to three independent certified energy auditors who serve Foster City and the surrounding area, chosen for the service you need. Your details are shared only with your consent.
Source: U.S. Census Bureau, Population Estimates Program (Vintage 2024) and Gazetteer Files (public domain), imported on 10/31/2026. Figures describe the incorporated place or county as published; they are shown for information only.