Insulation Company in Monrovia, CA
Blown in insulation solves a problem Monrovia homeowners know too well: rooms that bake in summer and never quite warm up on winter nights. Most homes here, particularly the craftsman bungalows and Spanish Colonials built between the 1920s and 1950s, have wall cavities that are either completely empty or filled with cellulose that settled decades ago. For homes in 91016 and 91017, the fix is usually blown in insulation that fills every gap without tearing into original plaster. Call Hollywood Insulation Co at (866) 605-6949 for a free estimate.
Why Monrovia Homes Are Different
Monrovia sits right at the base of the San Gabriel Mountains, which means summer afternoons routinely climb past 95°F while winter nights drop into the 40s. That wide daily temperature swing is exactly what insulation is supposed to handle, but the housing stock here makes it harder than it sounds. Homes in the historic core near downtown and the foothill neighborhoods north of Foothill Blvd were built in an era when insulation was an afterthought, if it was even thought about at all. Many still have knob-and-tube wiring in the walls, which means blowing in cellulose or fiberglass around old electrical lines requires care and a crew that’s done it before.
The south side of Monrovia is a different story. Newer developments there have standard batt insulation in the walls, but attics are often poorly sealed, so conditioned air leaks straight through the ceiling. And in the foothills, steep roofs and tight attic access mean insulation teams frequently work from the exterior or use injection methods that don’t require crawling through a cramped scuttle. It’s a town where two houses on the same street can need completely different approaches.
The dry climate adds another layer. Monrovia doesn’t get much rain, so air leaks aren’t just an energy problem – they’re an open door for dust and pests. A proper air seal before insulation goes in matters more here than homeowners expect.
Our Main Monrovia Services
Most calls from Monrovia break into two categories: attic insulation for homes with poor ceiling performance, and spray foam for older walls and hard-to-reach cavities. Here’s what each one looks like on the ground.
Attic Insulation in Monrovia
Attics in the older Monrovia homes near downtown often have nothing but a thin layer of dust where insulation should be. The job starts with assessing what’s there, sealing ceiling penetrations, and then installing blown in material or batts matched to the home’s framing. Peak summer cooling bills are usually the reason homeowners finally call. We work in tight Monrovia attics every week, including those with limited access in the foothill homes, and we can usually finish a standard attic in one day. See Attic Insulation in Monrovia for the full breakdown.
Spray Foam Insulation in Monrovia
When Monrovia walls are empty or filled with settled old material behind 1920s plaster, spray foam is often the only practical upgrade without ripping open the wall. We use injection methods through small holes, or open-cell systems like Icynene for attic rooflines that need both R-value and air sealing. The technique depends on the wall cavity, the wiring, and whether you’re dealing with a Spanish Colonial or a southside ranch. Read more at Spray Foam Insulation in Monrovia.
What happens when you call
- 1
A real person answersNo phone trees — you reach a local pro.
- 2
You get an upfront price rangeHonest numbers before anyone is dispatched.
- 3
A background-checked tech heads outLicensed & insured, dispatched right away.
- 4
You approve before work beginsNothing starts until you say go.
Blown In Insulation in Monrovia
Blown in insulation is the most common request we get from homeowners in Monrovia’s older neighborhoods, and for good reason. Homes built between the 1920s and 1950s in the historic core near downtown and the foothill streets north of Foothill Blvd frequently have wall cavities with no insulation at all, or old cellulose that has settled to half its original height. Blown in material lets us fill those cavities through small holes without disturbing original plaster or triggering the code upgrades that often come with opening up walls. In a climate with 95°F summers and cool winter nights, the difference after a proper blow-in is immediate. We install both cellulose and fiberglass systems, and if you want the full scope of what’s involved, see Blown In Insulation on our main service page.
Cellulose Insulation
Signs you need it
Rooms facing the afternoon sun in older Monrovia bungalows get hot within minutes of the AC cycling off, a classic sign wall cavities are empty or near empty.
What it costs in Monrovia
Blown in cellulose in Monrovia typically runs $1.20 to $2.50 per square foot installed, depending on wall density and whether we’re working around knob-and-tube wiring.
How we do it
We drill small access holes through exterior stucco or interior plaster, blow in GreenFiber cellulose at the right density, then patch and texture the holes to match.
Blown In Attic Insulation
Signs you need it
Your upstairs hallway is noticeably warmer than the rest of the house in summer, and you can see the ceiling joists in the attic because there’s barely any material up there.
What it costs in Monrovia
Attic blow-in work in Monrovia usually falls between $1.50 and $3.00 per square foot, with most standard attics landing around $1,800 to $3,500 all-in.
How we do it
We seal all ceiling penetrations first, then blow fiberglass or cellulose to the target R-value, keeping soffit vents clear so the roof assembly still breathes.
Blown In Fiberglass Insulation
Signs you need it
The walls feel hollow when you knock on them, or a remodeler discovered empty cavities while doing unrelated work in a 1950s ranch on the south side.
What it costs in Monrovia
Blown in fiberglass in Monrovia typically costs $1.50 to $2.80 per square foot, slightly less than spray foam for the same wall cavity.
How we do it
We drill and blow fiberglass through holes sized to minimize patching, checking fill density with a thermal camera before we close anything up.
What Blown In Insulation Costs in Monrovia
| Item | Typical range in Monrovia |
|---|---|
| Blown in attic insulation (installed) | $1.50 – $3.00 per sq ft |
| Blown in wall insulation (existing home) | $1.20 – $2.80 per sq ft |
| Air sealing before blow-in | $350 – $900 per attic |
Does blown in insulation settle over time?
Cellulose settles about 10% after installation unless it’s dense-packed. We account for that by installing at settlement depth so your walls don’t lose R-value. Fiberglass settles less but still needs proper density at install.
Can you blow insulation into walls without removing the plaster?
Yes. We drill small access holes from the exterior or interior, blow the material in under pressure, and patch the holes. Original 1920s plaster stays intact, and you avoid opening walls.
Brands We Service in Monrovia
We stock and install Rockwool mineral wool, CertainTeed fiberglass, and both Icynene and Demilec spray foam systems for Monrovia jobs. Parts and material are loaded for this area weekly, so most projects start within a few days. Our brands page lists the full lineup and what each material does best.
Pricing for Insulation Company in Monrovia, CA
| Service | Typical range in Monrovia |
|---|---|
| Blown in attic insulation | $1.50 – $3.00 per sq ft |
| Blown in existing wall insulation | $1.20 – $2.80 per sq ft |
| Spray foam attic roofline | $2.80 – $5.50 per sq ft |
| Spray foam rim joist | $3.50 – $6.00 per linear ft |
| Spray foam existing walls (injection) | $2.50 – $5.00 per sq ft |
| Batt insulation for attics | $1.80 – $3.20 per sq ft |
| Air sealing (standalone) | $600 – $1,900 per home |
| Attic insulation removal and reinstall | $1.50 – $2.50 per sq ft |
Two things push prices up in Monrovia more than anything else: knob-and-tube wiring that requires careful workarounds, and steep foothill roofs that slow down access. We give an upfront price before work starts, and the number on the quote is the number you pay.
Neighborhoods We Serve in Monrovia
We cover all of Monrovia, from the historic bungalows near Old Town to the foothill streets north of Foothill Blvd and the newer subdivisions south of the 210. Our crew is based close enough that we can usually be on site within one to two days for estimates.
- Old Town Monrovia
- North Monrovia foothills
- Monrovia Heights
- South Monrovia (91016)
- East Monrovia near Mayflower
Service Area – Cities Near Monrovia
Beyond Monrovia, we regularly run jobs in the neighboring foothill communities. Mayflower Village, CA is just minutes north of the 210 and has a similar stock of 1950s homes with thin attic coverage. Duarte, CA and Bradbury, CA have larger lots and a mix of older and newer construction, while Arcadia, CA brings more mid-century ranches with settling issues.
Serving Monrovia, CA — Our Local Coverage Area
We’re based in the Monrovia area and know this community well. Use the map below to see our service coverage — if you’re nearby, we can almost certainly help.
FAQs About Insulation Company in Monrovia
We usually schedule estimates within one to two business days across Monrovia. Since our crews work this area regularly, we can often work around a homeowner’s schedule rather than asking you to wait a week. Call (866) 605-6949 and we’ll lock in a time.
Most insulation-only projects in Monrovia don’t require a permit, but if the work touches knob-and-tube wiring or triggers code upgrades in older homes, the city may want an electrical sign-off. We’ll tell you upfront if your project crosses that line.
Yes. We’ve insulated homes throughout Old Town and the foothill neighborhoods north of Foothill Blvd, including homes with original plaster and knob-and-tube wiring. We use methods that don’t disturb protected exterior finishes or require structural changes.
What happens when you call
- 1A real person answersNo phone trees — talk to a local insulation pro.
- 2You get an upfront price rangeHonest numbers before anyone is dispatched. No surprises.
- 3A background-checked tech heads outLicensed & insured, typically within 30–60 min.
- 4You approve before work beginsNothing starts until you say go.
What Monrovia Customers Say
"Found and sealed a gap around the chimney chase that was basically an open chimney to the attic."
— Brandon Wong"Work is good and the house is noticeably more comfortable. There was insulation debris left in the hall closet under the attic access that I had to clean up."
— Miguel Garcia"Plastic laid from the front door to the attic hatch and they vacuumed the hallway afterward."
— Heather Walsh