Complete Guide to Home Insulation

Types of insulation, where to insulate, and energy-saving tips

5 Articles • 35 min read

Lower your energy bills by 15-20%. Proper insulation is one of the best investments you can make in your home. This guide shows you everything you need to know about insulation types, where to insulate, and how to save money.

Why Insulation Matters

💰 Save $200-600 per year on energy bills
🏠 Increase home resale value
♻️ Reduce carbon footprint by 10%
🌡️ Improve year-round comfort
🔇 Reduce noise from outside

1. Understanding R-Value

R-Value measures insulation's resistance to heat flow. Higher R-value = better insulation.

Recommended R-Values by Climate Zone

Location	Attic	Walls	Floor
Warm (South)	R30-R49	R13-R15	R13
Mixed	R38-R60	R13-R21	R19-R25
Cold (North)	R49-R60	R13-R21	R25-R30

💡 Check Your Current Insulation

Measure attic insulation depth. If fiberglass, multiply inches by 3 for approximate R-value. (6 inches = R18, 12 inches = R36)

2. Types of Insulation

Fiberglass Batts

Cost: $$ | R-Value: R2.9-R3.8 per inch | DIY: ✅ Easy

Best for: Attics, walls, floors between exposed joists

Pros: Affordable, easy DIY installation, widely available

Cons: Can compress (reduces R-value), needs vapor barrier, itchy to install

Blown-In Fiberglass

Cost: $$ | R-Value: R2.2-R2.7 per inch | DIY: ⚠️ Medium

Best for: Attics, tight spaces, irregular areas

Pros: Fills gaps completely, good for retrofits

Cons: Requires rental equipment, can settle over time

Cellulose

Cost: $$ | R-Value: R3.2-R3.8 per inch | DIY: ⚠️ Medium

Best for: Attics, dense-pack walls

Pros: Eco-friendly (recycled paper), fire-resistant treatment, good soundproofing

Cons: Can settle 20%, absorbs moisture

Spray Foam

Cost: $$$$ | R-Value: R3.5-R6.5 per inch | DIY: ❌ Professional Only

Best for: Air sealing, rim joists, cathedral ceilings

Pros: Highest R-value, air barrier, fills every gap

Cons: Expensive, requires professional installation, permanent

Rigid Foam Boards

Cost: $$$ | R-Value: R3.6-R6.5 per inch | DIY: ✅ Medium

Best for: Basement walls, exterior sheathing

Pros: High R-value per inch, moisture resistant

Cons: More expensive, requires cutting to fit

3. Where to Insulate (Priority Order)

🔴 Priority 1: Attic

Impact: 25-30% of heat loss

ROI: Pays for itself in 2-4 years

Cost: $1,500-3,000 (DIY) | $2,500-5,000 (pro)

How to Insulate Attic:

Air seal first (caulk gaps, seal penetrations)
Install baffles at eaves to maintain ventilation
Add insulation to reach R38-R60 total
Don't cover recessed lights (unless IC-rated)
Maintain ventilation (don't block soffit vents)

🟡 Priority 2: Walls

Impact: 20-25% of heat loss

ROI: 4-8 years

Cost: $3,000-8,000 (blown-in retrofit)

Options for Existing Walls:

Blown-in insulation through small holes
Insulate during renovation (open walls)
Interior insulation + drywall (reduces room size)
Exterior insulation + new siding (expensive but best)

🟡 Priority 3: Basement & Crawl Space

Impact: 10-20% of heat loss

ROI: 5-10 years

Cost: $1,500-4,000

Basement Insulation:

Insulate walls with rigid foam (R10-R15)
Insulate rim joists (huge air leakage area)
Don't insulate ceiling (wastes conditioned air)

Crawl Space:

Encapsulate with vapor barrier on ground
Insulate walls, not floor above
Seal all vents in encapsulated crawl space

🟢 Priority 4: Floors Above Unheated Spaces

Impact: 10-15% of heat loss

Cost: $1,000-2,500

Insulate floors above garages, porches
Use batts between joists with vapor barrier up
Support with wire mesh or strapping

4. DIY vs. Professional Installation

✅ Good DIY Projects

Attic Insulation (Batts or Blown-In)

Difficulty: Medium | Savings: 40-60%

Tools needed: Respirator, safety glasses, gloves, stapler/blower rental

Time: 1-2 days for average attic

Basement Wall Insulation (Rigid Foam)

Difficulty: Medium | Savings: 30-50%

Tools needed: Foam board, adhesive, saw, caulk

Time: 2-3 days

❌ Hire a Pro For:

Spray foam insulation (requires specialized equipment)
Wall insulation in existing walls (blown-in)
Crawl space encapsulation
Removing old insulation (especially asbestos)
Homes with knob-and-tube wiring

⚠️ Safety Warnings

Always wear respirator, long sleeves, gloves
Never stand on ceiling joists (only on boards)
Ensure adequate ventilation while working
Check for asbestos before disturbing old insulation
Never cover recessed lights (unless IC-rated)

5. Calculating Your Savings

Average Savings by Project

Project	Cost	Annual Savings	Payback Period
Attic insulation (DIY)	$1,500-2,500	$300-600	3-5 years
Wall insulation	$4,000-7,000	$250-450	10-15 years
Basement insulation	$2,000-3,500	$200-350	7-12 years
Air sealing	$300-600 (DIY)	$150-300	2-3 years

💡 Don't Forget Air Sealing!

Air sealing is just as important as insulation. Seal gaps with caulk and expanding foam before adding insulation. Common leak spots:

Around windows and doors
Electrical boxes and outlets
Plumbing penetrations
Attic hatch
Chimney chase
Recessed lights

Tax Credits & Rebates

Check for available incentives:

Federal Energy Tax Credits (30% up to certain limits)
State and local utility rebates
Low-interest financing programs
Weatherization assistance (income-qualified)

Start Saving Today

Insulation is one of the best home improvement investments. Start with your attic, seal air leaks, and watch your energy bills drop. The savings last for decades!