How much does it cost to install a radiant barrier?

HomeAdvisor's June 2026 guide gives $710 to $2,840 for a typical job, $1,700 on average. Material is $0.10 to $0.50 per square foot for one-sided foil, $0.50 to $0.90 for two-sided and $0.65 to $1.00 for spray-on, and labor $0.60 to $1.00 per square foot.

How many square feet of radiant barrier do I need?

The area of the underside of the roof deck, plus the gable end walls if you cover them. That is the attic floor area times the slope factor for the pitch: 1.118 at 6 in 12 and 1.414 at 12 in 12. A 40 by 28 ft attic at 6 in 12 needs 1,252 sq ft on the deck and 196 sq ft on the gable walls.

Is radiant barrier priced by attic size or roof area?

HomeAdvisor's table is keyed to attic size, at $0.70 to $2.00 per square foot of attic. The foil covers the roof, which is larger than the attic floor at any pitch, so check which area a quote is based on.

How much does spray-on radiant barrier cost?

HomeAdvisor gives $0.65 to $1.00 per square foot, or $250 to $400 per five-gallon bucket, and says spray-on barriers typically reach only about 75% reflectance.

What is the difference between one-sided and two-sided radiant barrier?

HomeAdvisor describes one-sided foil as reflective on one face only, at $0.10 to $0.50 per square foot, and two-sided as reflective on both, at $0.50 to $0.90.

Home › Insulation › Radiant Barrier Calculator

Radiant Barrier Calculator

Roof deck area from the attic plan and pitch; prices from HomeAdvisor's June 2026 guide

A radiant barrier goes on the underside of the roof, and a sloped roof has more area than the attic floor beneath it: 12% more at 6 in 12, 41% more at 12 in 12. HomeAdvisor's price table is keyed to attic size. This calculator works out the area the foil actually covers and prices both.

The attic and the barrier

Attic length

Attic width

Roof pitch

in 12

Roof shape

Cover the gable end walls

Barrier

Attic length and width are the floor inside the walls. Pitch is inches of rise per 12 in of run.

Specification summary

Generated from on . Reopen that address to reproduce these figures exactly.

Entered

Result

Published ranges for the jobs entered

Radiant barrier prices

As each row states
Item	Low	High	Unit
Radiant barrier, typical project	$710	$2,840	total
One-sided foil	$0.10	$0.50	per sq ft
Two-sided foil	$0.50	$0.90	per sq ft
Spray-on	$0.65	$1	per sq ft
Labor	$0.60	$1	per sq ft
500 sq ft attic, all in	$350	$1,000	total
1,000 sq ft attic, all in	$700	$2,000	total
1,500 sq ft attic, all in	$1,050	$3,000	total
2,000 sq ft attic, all in	$1,400	$4,000	total
Spray-on, five-gallon bucket	$250	$400	each
Attic fan	$625	$625	average

Source: HomeAdvisor, how much does a radiant barrier cost. Last price check: September 16, 2026.

The size table is keyed to attic size and works out to exactly $0.70 to $2.00 per sq ft at every row. The same guide says the material covers the attic's roof, walls and floor, which is more area than the attic floor.

Worked example

A 40 by 28 ft attic under a 6 in 12 gable roof, one-sided foil, gable ends covered.

Deck. 1,120 sq ft × √(1 + 0.5²) = 1,120 × 1.118 = 1,252 sq ft.
Gable ends. 2 triangles, 28 ft wide and 7 ft high: 28 × 28 × 6 ÷ 24 = 196 sq ft.
Barrier. 1,448 sq ft × ($0.10 to $0.50 material + $0.60 to $1.00 labor) = $1,014 to $2,172.
The size table on the floor. 1,120 × $0.70 to $2.00 = $784 to $2,240.

The foil covers 29% more area than the floor. The size table's low end prices only the floor.

The formula

Plain geometry, then HomeAdvisor's rates:

deck = floor × √(1 + (pitch ÷ 12)²) gable ends = width² × pitch ÷ 24

floor: attic length × width, sq ft
pitch: rise in inches per 12 in of run
gable ends: two triangles, each half the width times the ridge height

Cost = barrier area × (material rate + labor rate).

Where the numbers come from

The area is geometry: a plane sloped at a given pitch is longer than its horizontal projection by the square root of one plus the pitch squared. It needs no source and none is claimed.

The prices are HomeAdvisor's, from its radiant barrier guide updated 19 June 2026 and read on 16 September 2026. That guide says the material covers the attic's roof, walls and floor; this page covers the roof and, if you choose, the gable walls.

The table prices the floor, the foil covers the roof

HomeAdvisor's radiant barrier guide keys its price table to attic size: $350 to $1,000 for 500 sq ft, $700 to $2,000 for 1,000 sq ft, and so on up to 2,000. Every row works out to exactly $0.70 to $2.00 per square foot: its cheapest material plus its lowest labor rate at one end, and spray-on at $1.00 plus its highest labor rate at the other.

An attic floor is not what the foil covers. It goes on the underside of the roof, and a pitched roof is longer than the floor it spans.

Roof deck area over 1,000 sq ft of attic floor
Pitch	Deck area	More than the floor
4 in 12	1,054 sq ft	5%
6 in 12	1,118 sq ft	12%
8 in 12	1,202 sq ft	20%
10 in 12	1,302 sq ft	30%
12 in 12	1,414 sq ft	41%

On a gable roof the two end walls add more: two triangles whose area grows with the square of the house width. A 28 ft wide attic at 6 in 12 has 196 sq ft of gable wall.

So a quote per square foot of attic and a quote per square foot of barrier are different numbers for the same job. Ask which one you are being given.

Hip or gable does not change the deck area

A roof pitched the same on every face has a deck area equal to its plan area times the same slope factor, whatever its shape. A hip roof over a 40 by 28 ft attic has the same deck area as a gable roof over it, 1,252 sq ft at 6 in 12. What differs is the walls: a hip roof has none to cover.

That holds for the deck inside the attic. The shingled area outside is larger, because it includes the overhang, and that is the area the roofing calculator works with.

Frequently asked questions

How much does it cost to install a radiant barrier?: HomeAdvisor's June 2026 guide gives $710 to $2,840 for a typical job, $1,700 on average. Material is $0.10 to $0.50 per square foot for one-sided foil, $0.50 to $0.90 for two-sided and $0.65 to $1.00 for spray-on, and labor $0.60 to $1.00 per square foot.
How many square feet of radiant barrier do I need?: The area of the underside of the roof deck, plus the gable end walls if you cover them. That is the attic floor area times the slope factor for the pitch: 1.118 at 6 in 12 and 1.414 at 12 in 12. A 40 by 28 ft attic at 6 in 12 needs 1,252 sq ft on the deck and 196 sq ft on the gable walls.
Is radiant barrier priced by attic size or roof area?: HomeAdvisor's table is keyed to attic size, at $0.70 to $2.00 per square foot of attic. The foil covers the roof, which is larger than the attic floor at any pitch, so check which area a quote is based on.
How much does spray-on radiant barrier cost?: HomeAdvisor gives $0.65 to $1.00 per square foot, or $250 to $400 per five-gallon bucket, and says spray-on barriers typically reach only about 75% reflectance.
What is the difference between one-sided and two-sided radiant barrier?: HomeAdvisor describes one-sided foil as reflective on one face only, at $0.10 to $0.50 per square foot, and two-sided as reflective on both, at $0.50 to $0.90.

Check these numbers yourself

How Much Does a Radiant Barrier Cost?HomeAdvisor, updated 2026-06-19, read 2026-09-16.

How every figure here is verified: Sources & Method. Who builds this: Lucas Pradella, and the method is on About. Found something wrong? Tell us and it gets fixed or removed.

Figures on this page last checked against the source documents on 2026-09-16. Codes are amended locally; confirm against the edition your jurisdiction enforces.

Related calculators

The prices are HomeAdvisor's, read on 16 September 2026, and none is this site's. The area is geometry for a roof of one pitch with no dormers; measure a complex roof face by face.