How Much Does Insulation Cost?

Larger homes or multi-story buildings naturally require more insulation. Complex architectural features, such as vaulted ceilings and irregular layouts, can increase time and material requirements.

Whether the home is brand-new or existing construction also matters. In new construction, open cavities make installation faster and typically more affordable. However, retrofitting in existing homes can require drilling for dense-packing which increases labor costs.

Energy Star reports that 9 out of 10 U.S. homes are under-insulated. Many older Delaware homes were built with minimal insulation or outdated materials that have settled or deteriorated over time.

Upgrading older insulation usually costs more upfront, but the energy savings tend to be much greater and more immediate.

Sometimes removal is required before installing new insulation, especially if the old materials are:

• Moldy
• Pest-infested
• Water-damaged
• Non-compliant with today’s code

Safe removal and disposal add to the project cost, especially for potentially hazardous materials. Delmarva Insulation does not remove vermiculite insulation, which may contain asbestos. New construction avoids this issue, while older homes undergoing renovation should take it into account.

Different parts of the home have different price ranges:

• Attics: Generally the most cost-effective and highest-impact area for price, easiest to access.
• Walls: More labor-intensive, especially in finished homes.
• Crawl spaces and basements: Often require moisture-resistant insulation, such as rigid foam or closed-cell spray foam.
• Floors over garages or other unheated spaces: Require additional labor to access.

In summary, newer, smaller homes with open access fall on the lower end of the investment scale. Larger or older homes with enclosed cavities and outdated materials fall on the higher end. Material choice is the next major cost factor.

Fiberglass, available in batts or blown-in loose-fill, is one of Delaware’s most affordable insulation materials, falling at the lower end of the material pricing tier. It offers strong performance per dollar, is widely available, and works well in:

• Attics
• Open wall studs
• Floor joists
• Retrofit applications through small access holes

Some benefits of fiberglass include affordability, availability, noncombustibility, and moisture resistance. However, fiberglass does not air-seal on its own (manual air sealing can be added separately) and loses effectiveness when compressed. Fiberglass insulation remains the most economical choice for many Delaware homeowners.

Cellulose is made from recycled paper fibers and fire-retardant treatments. It typically costs slightly more than fiberglass but remains cost-effective. Typical uses include blown-in attic insulation or dense-packing it into walls.

Advantages include good air-blocking performance when dense-packed and eco-friendliness, given its high recycled content. Potential downsides include settling over time and vulnerability to moisture if leaks occur. However, it is a popular choice for older home upgrades, including attic and wall retrofits.

Mineral wool is made from rock or slag fibers and is valued for its superior fire resistance and sound-dampening qualities. Available in batts or loose-fill, it typically costs more (roughly 25% or above) than fiberglass and cellulose, making it a mid-range option. It’s ideal for:

• Walls, floors, and ceilings
• Townhome or condo shared walls
• Furnace rooms or mechanical spaces

It offers the benefits of being highly fire-resistant, excellent sound-dampening, and maintaining its R-value even when wet. However, it also comes with a higher upfront investment, is more rigid to handle, and usually requires professional installation. It is ideal when fire codes or acoustic comfort are priorities.

Spray foam, available in open-cell and closed-cell varieties, has the highest upfront investment. Closed-cell provides an exceptional R-value per inch (around R-6), a built-in air barrier, and moisture resistance.

Applications include:

• Rim joists
• Crawl spaces
• Sealed attics
• Irregular or hard-to-reach cavities

Spray foam provides both insulation and an air barrier, fills cracks, reduces drafts significantly, and even adds structural integrity to buildings when used with closed-cell foam. It requires the highest initial investment and requires professional installation, but offers significant long-term energy savings and comfort improvements, and many Delaware homeowners find the payoff worth it.

Rigid foam (polyiso, XPS, EPS) offers high R-value per inch and is positioned in the moderate-to-high investment tier per square foot. It is commonly used in:

• Basement walls
• Crawl space walls
• Exterior sheathing
• Attic knee walls

Delaware’s 2018 IECC code allows combinations such as R-13 cavity insulation and R-5 continuous exterior foam for wall assemblies. Continuous insulation helps reduce thermal bridging, acts as a vapor and moisture barrier, and can help improve whole-home efficiency. It is a higher investment than fiberglass, and given its installation process of sealing and cutting the boards, it requires professional installation. This makes it ideal for new construction or major renovations of existing homes focusing on foundations and external walls.

In summary, while the overall cost of installing insulation varies, the material price plays a part in determining the final cost. Fiberglass and cellulose fall into the budget tier, offering strong performance at the most accessible price point. Mineral wool and rigid foam sit in the mid-range tier, providing higher fire resistance, sound control, or continuous insulation benefits at a moderate increase in cost. Spray foam is considered the premium option thanks to its superior air sealing and high R-value per inch. In practice, many Delaware projects use a strategic combination of materials, such as fiberglass in open attics, spray foam at rim joists or other major leak points, and rigid foam boards along basement or crawl space walls to manage moisture and improve overall efficiency.

Insulation is one of the few home projects that starts paying you back immediately. ENERGY STAR estimates that sealing and insulating can save homeowners around 15% on heating and cooling costs and 11% on total energy use. According to EnergyCodes.gov, Delaware households that follow the 2021 standards can reduce overall energy consumption by 9.8%, translating to about $276 in annual savings. Better insulation also reduces strain on HVAC systems, extending their lifespan and lowering maintenance expenses.

But it’s not just a financial benefit. Efficient insulation results in additional comfort in your home, including more even temperatures throughout the house, fewer drafts and hot/cold spots, improved indoor air quality, and less dust, pollen, and outside noise entering the home.

Most insulation upgrades offer a 5–8 year payback period, depending on home age and material choices. Quality modern materials last decades, making insulation one of the highest-ROI improvements Delaware homeowners can make.

On a sustainability note, reduced energy consumption and greenhouse gas emissions result in a more environmentally friendly home, something increasingly valued by Delaware homebuyers.

A quick attic check can clue you into whether you’re under-insulated. If you can see the ceiling joists, you probably need more insulation. ENERGY STAR confirms that most U.S. homes, including many in Delaware, don’t meet recommended levels. Once you’ve confirmed your insulation needs, prioritize important areas. Attics are often the easiest and most effective for quick savings, and you can combine air sealing with insulation for maximum effectiveness. By air sealing and insulating your attic or crawl space, you’ll immediately save around 15% on heating and cooling costs.

To proceed with an effective insulation project, match the material needed for the proper area.

• Fiberglass or cellulose for large open areas
• Spray foam for major air-leak points
• Rigid foam for below-grade or moisture-prone areas
• Mineral wool where fire resistance or sound control matters

New construction must meet R-49 ceilings, R-20 walls, and R-10 to R-13 basement/crawl wall requirements. Existing homes aren’t required to meet new-build standards, but using them as guidelines can improve comfort and efficiency.

Every home is different. A professional assessment helps identify air leakage points, moisture concerns, material compatibility, and the best-value upgrades. Be sure to obtain multiple quotes to receive competitive pricing. While DIY may be feasible for some projects, professional installation is crucial to ensure optimal performance.

Delaware residents may also qualify for assistance programs such as the Weatherization Assistance Program, which helps eligible households reduce energy costs.

Insulating a Delaware home is one of the smartest investments you can make for comfort, efficiency, and long-term savings. The total cost varies depending on climate zone requirements, the home’s size and age, the areas being insulated, and the materials selected, but Delaware’s building codes and climate mean most homes benefit from substantial insulation upgrades to stay comfortable year-round. Choosing materials strategically helps you manage your budget while still maximizing performance. Fiberglass offers a reliable, budget-friendly option for many projects, and premium choices like spray foam or rigid foam deliver significant efficiency gains when air leakage or moisture control are concerns. The payoff is a more comfortable home and meaningful annual energy savings, often amounting to hundreds of dollars.

Ready to upgrade your home’s comfort and efficiency? Contact Delmarva Insulation for expert guidance, solutions tailored to Delaware homes, and detailed project estimates.

References:

Ardor Construction. (n.d.). Different types of attic insulation and cost. https://www.ardor.construction/energy-efficient-insulation-contractor-services/different-types-of-attic-insulation-and-cost

Certified Roofing Solutions LLC. (n.d.). Attic insulation cost. https://certifiedroofingsolutionsllc.com/blog/attic-insulation-cost/

Delaware.gov. (n.d.). Facts about Delaware. State of Delaware. https://delaware.gov/guides/facts/#:~:text=Delaware%27s%20climate%20is%20moderate%20year,from%20170%20to%20200%20days

Delaware Department of Natural Resources and Environmental Control. (n.d.). Weatherization Assistance Program. https://dnrec.delaware.gov/climate-coastal-energy/sustainable-communities/weatherization/#:~:text=Weatherization%20Assistance%20Program%20,by%20weatherproofing%20and%20improving

HomeAdvisor. (n.d.). How much does insulation cost? https://www.homeadvisor.com/cost/insulation/#:~:text=HomeAdvisor%20www,Mineral%20Wool

HomeGuide. (n.d.). Insulation cost. https://homeguide.com/costs/insulation-cost

Insulation Institute. (2020). Delaware residential energy code summary. https://insulationinstitute.org/wp-content/uploads/2020/08/DE_Code-FINAL.pdf#:~:text=Prescriptive%20R402,SUMMARY%20OF%20KEY%20RESIDENTIAL%20ENERGY

This Old House. (n.d.). Spray foam insulation cost. https://www.thisoldhouse.com/roofing/spray-foam-insulation-cost#:~:text=Spray%20foam%20insulation%20is%20considerably,need%20to%20hire%20a%20professional

U.S. Department of Energy. (2021). Delaware residential cost effectiveness. Energy Codes. https://www.energycodes.gov/sites/default/files/2021-07/DelawareResidentialCostEffectiveness_2021.pdf#:~:text=Moving%20to%20the%202021%20International,over%2030%20years%20by%203%2C704%2C000

U.S. Environmental Protection Agency. (n.d.). Insulation R-values. ENERGY STAR. https://www.energystar.gov/saveathome/seal_insulate/identify-problems-you-want-fix/diy-checks-inspections/insulation-r-values#:~:text=4A%20and%204B

U.S. Environmental Protection Agency. (n.d.). Why seal and insulate? ENERGY STAR. https://www.energystar.gov/saveathome/seal_insulate/why-seal-and-insulate#:~:text=Air%20that%20leaks%20through%20your,over%20crawl%20spaces%20and%20basements