High PG&E bill? Insulation, air sealing and a home energy check

For Silicon Valley homes · Updated October 2026 · Sources below

If your bill jumps in winter or summer, heating and cooling are usually the place to look, and leaky, under-insulated homes lose a lot of it. Sealing air leaks and adding attic insulation are some of the cheapest upgrades: ENERGY STAR says they can cut heating and cooling costs by up to 15%. A home energy check shows where your home loses the most.

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The short version

Sealing and insulating can save up to 15% on heating and cooling
Attic insulation level with or below the joists? You probably need more
Bay Area counties are in climate Zone 3: about R49 for an empty attic, R38 if it has 3-4 inches
Caulking and weatherstripping usually pay for themselves in a year or less
PG&E power costs the most from 4 to 9 p.m.

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What it costs

Add attic insulation$1,700 - $2,500
Air sealing$250 - $750
Home energy assessment$212 - $698

Attic size, access, removing old insulation and the material change the price.

Typical ranges from published cost guides - mostly national figures. Bay Area prices usually run higher. Your actual price depends on your home and the job, and a pro gives you the real number. Source: HomeAdvisor cost guide (national) (Jun 2026). Have a quote? Check it with the Quote Explainer

Signs your home is losing energy

Your attic insulation is level with or below the floor joists, or thin along the eaves
Drafts around doors, windows, outlets or where pipes and wires come through walls
Dirty spots on ceiling paint or carpet edges - a sign air is leaking through
Some rooms are always too hot or too cold
Heating and cooling bills jump sharply in winter and summer

What to do first

Start free: run PG&E's 5-minute Home Energy Checkup or SVHN's Energy Bill Check to see where your energy goes.
Look in the attic: if you can see the tops of the joists, you likely need more insulation. If you see vermiculite (pebbly loose fill), don't disturb it until a lab tests it for asbestos.
Seal before you insulate - caulk and weatherstrip the gaps, then add insulation on top.
For a full picture, hire a home energy professional for an energy audit; it can also spot safety issues.

In Silicon Valley

Santa Clara, San Mateo and Alameda counties are in climate Zone 3C. ENERGY STAR recommends R49 for an uninsulated attic there, R38 when adding to 3-4 inches already in place, and R19 for floors.
PG&E's time-of-use rates make power most expensive from 4 to 9 p.m. - a well-sealed, insulated home holds its temperature through those hours.
Palo Alto Utilities offers an attic insulation add-on rebate with a qualifying heat pump or other electrification rebate; it requires R-30 in attics and R-19 for Eichler and flat-roof homes.
PG&E customers can run PG&E's free 5-minute Home Energy Checkup in their online account to see how their energy splits between heating, hot water, appliances and lighting.

Questions homeowners ask

Why is my PG&E bill so high?

Often it's heating or cooling during a cold or hot spell, and using power from 4 to 9 p.m. costs the most on PG&E's time-of-use rates. Start with PG&E's free Home Energy Checkup or SVHN's free Energy Bill Check at /energy to see which upgrades might help your home most.

How do I know if my attic needs more insulation?

Look across the attic. ENERGY STAR says if the insulation is level with or below the floor joists, you probably need more; if you can't see the joists at all, adding more may not be worth it. Check the edges near the eaves too - they're often thin.

How much attic insulation do I need in the Bay Area?

Most of the Bay Area is in climate Zone 3. ENERGY STAR recommends about R49 for an attic with no insulation and R38 when adding to an attic that already has 3 to 4 inches.

Is air sealing worth it?

Usually, yes. The Department of Energy says caulking and weatherstripping often pay for themselves in a year or less. Common leaks are around doors and windows, behind outlet plates, and where pipes, ducts and wires pass through walls and ceilings.

How much does insulation cost?

National cost guides put attic insulation at about $1,700 to $2,500 and air sealing at about $250 to $750. Bay Area prices usually run higher, and removing old insulation adds to it.

What is a home energy audit and do I need one?

A home energy professional checks your home for air leaks, insulation gaps and equipment problems, and can spot safety issues. National cost guides put one at about $212 to $698. A free online check is a good first step if you're not sure where to start.

Rebates: Insulation

City of Palo Alto Utilities Rebate Hub
BayREN home energy programs

Rebate programs change often and money runs out. Amounts are from each program's page as of Oct 2026 - always confirm on the program page, and check whether you must apply before you buy or install.

See the rebates for your ZIP

Save with your neighbors

Home energy check is a job neighbors team up on: one pro, one trip down your street, a group price the pro sets. Three homes start it.

Start or join a Neighborhood Block Deal

Questions to ask the pro

Will you air seal before adding insulation?
What R-value will my attic have when you're done?
Does the old insulation need to come out first?
How will you keep the home properly ventilated after sealing?
Does this qualify for a rebate from my utility?

Before you sign, check the contractor's license at cslb.ca.gov. How to hire a contractor in California

Know a neighbor dealing with this?

Send them this page - it's free, and every answer has its sources.

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