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Lehi · Utah County · Climate Zone 5B

Attic Insulation in Lehi, Utah

The attic is where most Lehi homes lose the fight with January and July. It is also the cheapest place in the house to fix.

Lehi Elite Insulation installs blown-in attic insulation for homes across Lehi, from the older houses off Center Street to the newer builds on Traverse Mountain and in Holbrook Farms. We measure what you have, air seal the attic floor, and blow fiberglass or cellulose to Utah's R-49 code level or the R-60 the Department of Energy recommends for this climate. Free inspection, flat written price.

Call (801) 348-3113 Book a Free Attic Inspection

✓ Depth measured across the full attic footprint, not a glance from the hatch
✓ Air sealing included on every attic job, not billed as an upsell
✓ Baffles, insulation dams, and depth rulers installed so the coverage is verifiable

Get a free attic inspection

Takes about 30–45 minutes. No cost, no pressure.

Signs

How to tell your Lehi attic is under-insulated

You do not need a thermal camera. Most of the evidence is visible from the hatch or on your gas bill.

You can see the joists. Ceiling joists are usually 2x6 or 2x8. If the tops are visible, you have 6 to 8 inches at best, roughly R-19 to R-25. Code is R-49.
The second floor runs 5° off the first. Heat rises into an under-insulated attic in winter and radiates back down in summer. Upstairs bedrooms feel it first.
Ice dams after a storm. Heat escaping through the ceiling melts snow on the roof deck. It refreezes at the cold eaves. Ice at the gutter line means heat is leaving through the attic.
Gas bill spikes December through February. Utah County winters are cold and dry. A furnace fighting an R-19 attic runs far longer than one above R-49.
Uneven coverage from past work. HVAC or electrical crews push insulation aside and rarely put it back. Bare spots around ductwork and can lights leak heat like open windows.
The house was built before about 2005. Older Lehi homes were commonly finished at R-19 to R-30. Even newer builds settle and get compressed by storage.

The target

R-49 is the code minimum. R-60 is where the Department of Energy points Zone 5.

Utah adopted the 2021 IECC with state amendments effective July 1, 2024. For Climate Zone 5, which covers Lehi and all of Utah County, the prescriptive ceiling value is R-49.

Going from R-49 to R-60 once a crew and a blowing machine are already on site is a small incremental cost, a few more inches of material. That is why we quote both numbers and let you choose. The ThermWise attic rebate also requires the finished level to land between R-49 and R-60, so R-60 is the top of the rebate window, not beyond it.

Code values: Insulation Institute, Utah energy code summary (2025). Last checked September 30, 2026.

Typical attic R-values by build era

R-19

Built before 1990

R-30

1990s – early 2000s

R-49

Utah code minimum

R-60

DOE recommended for Zone 5B

General guidance for Utah homes, not a survey of specific houses. R-49 is roughly 16–18 inches of blown fiberglass. We measure your attic in several spots and give you the actual number.

Materials

Blown fiberglass vs. cellulose in a Lehi attic

Both are loose-fill products blown through a hose to a measured depth. They behave differently over time, and Utah's dry climate and bench wind change the math a little.

Factor	Blown-in fiberglass	Blown-in cellulose
R-value per inch (typical manufacturer rating)	About R-2.2 to R-2.7	About R-3.2 to R-3.8
Depth for R-49	About 16 to 18 inches	About 13 to 15 inches (blown deeper to allow for settling)
Settling	Minimal	Settles roughly 10 to 20 percent over the first years, so the install depth is set above target
Moisture	Does not absorb water	Absorbs moisture if the roof leaks, then dries slowly
Air movement	Lighter, so wind-washing at the eaves matters more. Baffles and dams fix this.	Denser, resists air movement better. Helpful on the bench where Point of the Mountain wind hits.
Fire and pests	Non-combustible glass	Recycled paper treated with borate for fire and pest resistance
Best fit	Most vented Lehi attics, and any attic with a history of roof leaks	Wind-exposed attics and anyone who prefers a recycled-content product

R-value ranges are typical manufacturer-rated values and vary by product and installed density. The number that matters is the measured depth after installation, which is why we install depth rulers.

Sequence

Air sealing first, then baffles, then insulation

Blowing 16 inches of insulation over an unsealed attic floor is a partial fix. Warm air still leaves through the gaps, it just takes a slightly longer route.

Every attic job we run starts with the attic floor. Top plates where the drywall meets the framing, plumbing and flue chases, bath fan housings, recessed can lights, wiring holes, and the attic hatch itself all get sealed with the right material for each spot. Fire-rated sealant goes around flues and chimneys. The hatch gets weatherstripping and a rigid insulated cover so the one door into the attic is not the biggest leak in it.

Next come the eaves. Vented attics need air to move from the soffit vents up to the ridge or roof vents. Blown insulation that spills into the soffit blocks that airflow and gets wind-washed thin. We install baffles at every rafter bay along the eaves and insulation dams around the hatch and any mechanical platforms so the material stays where it belongs at full depth.

Then we blow to depth. Depth rulers go in across the attic on the way out. They are the cheapest quality-control tool in the trade: anyone with a flashlight can check the coverage from the hatch for the next 30 years.

What comes with every attic job

Attic floor air sealing with fire-rated sealant at flues and chimneys
Rafter baffles at the eaves and dams around the hatch and platforms
Blown fiberglass or cellulose to the R-value in your written quote
Depth rulers and before-and-after photos
Drop cloths from the door to the hatch and a vacuum on the way out

Installer working on the floor of a residential attic before insulation is blown in — Air sealing happens on hands and knees across the attic floor before the blowing hose comes out. Stock photo, used to illustrate the step.

Before you add

When old attic insulation has to come out first

Most of the time it doesn't. Dry, uncontaminated insulation stays put and the new layer goes over the top. The old material still counts toward your R-value and pulling it out adds cost for no benefit.

Removal is the right call in four situations: rodent contamination (droppings, urine staining, nesting), water damage from a roof or plumbing leak, smoke or fire damage, and vermiculite that may contain asbestos. Vermiculite looks like small gray-brown or silver-gold pebbles. If you see it, stop and have it tested before anyone disturbs it.

When removal is needed we vacuum the old material out through a hose to a truck, sanitize the attic, then air seal and re-insulate as one continuous job with one price. Our insulation removal page covers the process and the rodent-first sequence in detail.

Active rodents? Get a pest control company to seal the entry points first. New insulation in an attic that mice can still reach will be contaminated again by next winter. We can point you to companies in Utah County that do exclusion work properly, then handle the removal and re-insulation once the house is sealed.

How it works

The attic job, start to finish

Free inspection

We walk the attic, measure depth in several locations, check the baffles and ventilation, and find the air leaks doing the real damage. About 30–45 minutes.

Written scope and price

Material, target R-value, air sealing scope, and any rebate you qualify for, in writing, flat priced. No "starting at," no day-of surprises.

Install

Walkways protected, penetrations sealed, baffles and dams set, insulation blown to depth, rulers installed. The schedule is in your quote.

Walkthrough

Before-and-after photos, confirmed depth readings, and the documentation a rebate application asks for.

Cost & rebates

What drives the price of attic insulation in Lehi

Attic insulation is priced by square footage of attic floor, current depth, target R-value, access, and how much air sealing the attic needs. A straightforward top-up on an accessible 1,500 square foot attic is a very different job from a low-clearance attic with knee walls and a contaminated layer that has to come out first.

Rather than post a "starting at" number that never survives contact with a real house, we quote flat after we have measured. The inspection is free, the quote is in writing, and the price doesn't move once you sign it.

Things that push the number up: removal, very low clearance, multiple attic sections, a lot of can lights and penetrations to seal, and going to R-60 instead of R-49. Things that keep it down: clear access, an existing dry layer we can build on, and a simple roof.

Get your flat written quote

Attic rebates for Lehi homes

ThermWise attic insulation, Tier 1 $0.32 per square foot when at least R-19 is added and the attic finishes between R-49 and R-60. Enbridge Gas customers. Contractor-installed work must come from a ThermWise authorized contractor.

ThermWise attic insulation, Tier 2 $0.08 per square foot when at least R-11 is added and the attic finishes between R-49 and R-60.

Wattsmart (Rocky Mountain Power) $0.10 per square foot for attics finishing at R-49 or more from R-19 or less. RMP customers only, so it does not apply to homes on Lehi City Power. Homes built in the last 10 years are excluded.

Amounts and rules are set by the utilities and change. See the full Utah insulation rebates guide for current terms, which utility serves your city, and a quick eligibility checker. Last checked September 30, 2026.

Older attic with exposed floorboards and thin insulation, typical of pre-1990 construction — Older attics with floorboards over the joists usually hide a thin, settled layer. Stock photo.

Around Lehi

Older Lehi vs. newer Lehi: two different attic problems

Lehi's housing stock splits cleanly at about the year 2000, and the attics split with it.

The older homes near Main Street and Center Street, and the original tracts north of the freeway, were built when R-19 was normal and R-30 was generous. Many have had nothing added since. The material is often compressed, sometimes disturbed by decades of storage and wiring work, and the attic floor was never air sealed. These attics get the biggest improvement per dollar of anything we do.

The newer subdivisions on Traverse Mountain, in Holbrook Farms, and along the Thanksgiving Point corridor were built to a more recent code, but builder-grade attic insulation is installed to the minimum on the day of inspection and not a fraction more. It settles, it gets pushed around by the HVAC and low-voltage crews who come after the inspector, and bare spots around the furnace platform and can lights are common. Wind exposure on the bench makes wind-washing at the eaves worse.

The inspection is the same either way. We measure in several spots, photograph what we find, and tell you the current R-value and what it takes to get to R-49 or R-60. The home's age just tells us where to look first.

Common questions

Attic insulation in Lehi, UT: FAQs

How much insulation should be in my attic in Lehi?

Utah's current energy code calls for R-49 in the ceiling for Climate Zone 5, which is roughly 16 to 18 inches of blown fiberglass or 13 to 15 inches of cellulose. The Department of Energy's recommendation for this zone goes up to R-60. If you can see the tops of your ceiling joists from the hatch, you are well under both numbers.

Can you blow new insulation over old?

Usually yes. If the existing material is dry, uncontaminated, and not vermiculite, we air seal the attic floor and blow new insulation directly over the old layer. The old layer still counts toward your total R-value. Removal is only needed when the old insulation is wet, rodent-contaminated, smoke-damaged, or suspected to contain asbestos.

Fiberglass or cellulose for a Utah attic?

Both work in a vented Utah attic. Blown fiberglass resists settling and moisture. Cellulose is denser and blocks air movement a little better, which matters on the bench where the Point of the Mountain wind is a factor, but it settles over time so it has to be blown above target depth. We recommend based on what is already up there and how the attic is vented.

Do I need a permit to add attic insulation in Lehi?

Adding insulation to an existing attic is normally treated as maintenance and does not require a permit on its own. If the job is part of a larger remodel or finish that already needs a permit, insulation gets inspected as part of that. Lehi City Building has the final say, and we will tell you if your project falls into the second category.

How long does attic insulation take?

An air seal plus blow-in on a typical single-family attic is usually a same-day job. Removal of old material first adds time. Your written quote spells out the schedule so there are no surprises.

Does attic insulation help in summer?

Yes, and it is underrated. A Lehi attic can reach 140°F in July. A full layer of insulation slows that heat from radiating down through the ceiling, which is why upstairs bedrooms notice the change most.

Will I qualify for a ThermWise rebate?

If your home has natural gas from Enbridge Gas, ThermWise pays $0.32 per square foot when at least R-19 is added and the attic finishes between R-49 and R-60. A smaller Tier 2 rebate applies when at least R-11 is added. Contractor-installed work must be done by a ThermWise authorized contractor. Our rebates guide has the full rules and a checker.

Other work that often goes with this

Free inspection

Find out what is actually in your attic

The inspection is free and takes under an hour. Worst case, you learn your insulation is fine and stop wondering about it every time the furnace kicks on.

Call (801) 348-3113

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Call (801) 348-3113 for a Free Inspection