Insulation

For optimal energy efficiency, your home should be insulated from the roof down to two feet below ground level. Insulation’s ability to reduce heat transfer is rated in terms of its R-value, with a higher R-value making the home more efficient and comfortable. Efficiency Maine recommends that the entire building envelope be insulated: attics, cathedral ceilings, all wall cavities, rim joists, basement walls, and crawl spaces.

Increasing the amount of insulation in your home can have the following advantages:

• Lower Heating and Cooling Costs – Effective insulation means that it takes less energy to make your home comfortable and reduces your costs.
• Increased Year-Round Comfort – Insulation helps keep rooms warmer in the winter and cooler in the summer.
• Reduced Outside Noise – Increased insulation levels may also make your home quieter by reducing the amount of outside noise that comes in.

Types of Insulation

There are many different types of materials used for insulation, each with their own costs, advantages, and disadvantages. A Residential Registered Vendor will be able to recommend appropriate insulation levels, tell you which insulation materials might work best in certain locations, and perform insulation work.

Here are some of the common types of insulation:

	Material	R-Value Per Inch	Advantages	Disadvantages
1	Fiberglass (loose blown)	3.6 to 4.4	Low cost	Performs poorly where there’s moving air, settles over time, can be irritating/itchy to install
2	Fiberglass (batt)	2.6 to 4.3	Low cost	Performs poorly where there’s moving air, settles over time, can be irritating/itchy to install
3	Celulose (loose blown)	3.2 to 3.6	Low cost, reduces drafts	Absorbs water, can be heavy, settles over time, may corrode metal if wet
4	Celulose (dense pack)	3.0 to 3.4	Low cost, reduces drafts	Absorbs water, can be heavy, may corrode metal if wet
5	Spray Foam (open cell)	3.5 to 3.8	Reduces drafts, lower price than closed cell foam	Not a moisture barrier, may require fire barrier
6	Spray Foam (closed cell)	6.0 to 7.0	Reduces drafts, serves as a moisture barrier	Highest upfront cost, may require fire barrier
7	Foam (board)	3.6 to 7.6	Reduces drafts, moisture resistant	May require fire barrier
8	Mineral Wool (batt)	3.0 to 3.6	Non-combustible, minimal off-gassing	Heavy, more compressible than fiberglass, fibers can be irritating
9	Mineral Wool (board)	4.0 to 4.4	Non-combustible, minimal off-gassing	Heavy, fibers can be irritating

Source: Residential Energy: Cost Savings and Comfort for Existing Buildings