Attic insulation cost in St. Louis, MO

How much does attic insulation cost in St. Louis?

Attic insulation in St. Louis typically costs $3,070 for the example home, with a range of $2,400 to $4,120. The job is blown cellulose in an open attic, brought up toward a planning target of R-60 for climate zone 4A. It is not closed-cell foam on the roofline, not wall insulation, and not a kneewall that has to be built before anyone can blow anything. The target is the one this site uses so cities can be compared. Confirm the energy code that actually applies before you treat R-60 as a legal minimum.

Why the St. Louis zone changes the price

Zone 4A is why the target is R-60 and not the same number as a Gulf city or a northern city. A hotter-or-milder zone uses less material in this model. A colder zone uses more. St. Louis has about 4,740 heating degree days and 1,550 cooling degree days. The national starting point for this house, before labor, is $3,110. Local labor at 0.98 saves about $40 versus a crew priced at 1.00. About 55 percent of the price is labor. The bags of cellulose are the rest, and they do not change much by city.

What the example attic is, and what yours might not be

The example home was built around 1952 and has about 1,550 square feet of floor, which this page treats as the attic area. brick houses and two-families, basements, humid summers and a real winter An open, walkable attic with a hatch is the typical price of $3,070. The low price, $2,400, is that attic when the hatch is easy and there is almost no old insulation to move. The high price, $4,120, is the same cellulose when the hatch is a closet ceiling, the baffles at the eaves take time, or a small amount of old material has to be raked. Knob-and-tube wiring, a wet attic, vermiculite, or a full removal before the new blow can sit above the high number. Those are different jobs. St. Louis brick houses with basements are workable for trades, and the labor factor sits just under national. Humidity in summer and a real heating season mean equipment actually runs both ways. The high column is a two-family with shared electric and a basement drain that does not work. This page is the Missouri side. East St. Louis and the Metro East are not silently included.

What insulation does not do to the other prices

A better attic does not change the furnace sticker on the furnace page, and it does not change the roof price. It can change the yearly bill, which is why the heating page exists separately. Do not let a contractor add “you’ll save the insulation back on the furnace” into one number with no yearly bill attached. At 13.2¢ per kilowatt-hour the cooling hours matter too. Ameren Missouri serves the Missouri side. The planning rate is under the national figure. The Illinois side of the river is a different utility and not this page. This page does not promise a payback.

If you rent in St. Louis

Blowing an attic is an owner’s project. A renter can use the range to read a proposal for the building, not to hire an insulation crew. An owner of a different size house should set square footage in the calculator. A 900 square foot bungalow and a 2,200 square foot house are not the same number of bags. Reviewed 2026-09-01. Planning model: IECC climate zone, degree-day normals, a metro labor factor, and a residential rate used only for operating-cost context. Installed costs start from published national ranges and scale the labor share. Rents are planning medians, not listings. Reviewed 2026-09-01.

Before you accept an insulation quote in St. Louis, ask what R-value is already there, what R-value they will leave, and whether air sealing at the hatch and the wire holes is included. The typical price of $3,070 assumes an open attic and a top-up toward R-60, at labor 0.98. If they are foaming the roof deck, stop using this table.