Insulation in Ellisville, Missouri

Insulation and air sealing in Ellisville

Ellisville runs to about 4.4 square miles and roughly 10,002 people. It sits about 20 miles west of downtown St. Louis. Around 4,349 housing units sit inside those boundaries, most of them built before anyone measured a house for air leakage. The community dates back to 1932. We cover ZIP codes 63011, 63021 and 63038.

No completed job in Ellisville is logged in our records yet, and this page will say so until one is.

The housing stock in Ellisville

The typical home in Ellisville dates to around the early-1980s. Houses of this vintage usually got batts or blown fibre at whatever the standard of the day was, which is well short of what is recommended now. Most are one top-up away from being right.

Mostly 1970s-80s subdivisions (about 26% built in the 1970s, 17% in the 1980s).

Settled before 1837, Ellisville incorporated as a village in 1932 (to create its own school district) and became a fourth-class city in 1957; Money magazine ranked it #25 on its 2009 'Best Places to Live in America' list.

What we usually find in a late-century house

Housing from this stretch in Ellisville generally got a real attempt at insulation — a real layer in the attic, batts in the walls — so the argument here is rarely about starting from nothing. It is about the gap between what was standard then and what is recommended now, and about the parts nobody insulated at all. Recurring finds: batts stuffed into the rim joist rather than sealed, insulation missing entirely above a cathedral or tray ceiling, soffit vents blocked solid by insulation blown over them with no baffles, and can lights punched straight through the ceiling plane. A house from this era is usually a top-up plus a day of sealing, not a rebuild.

What the energy code requires in Ellisville

Ellisville enforces the 2015 IRC Chapter 11 (Energy Efficiency). Section 500.010 of the Ellisville code adopts twelve codes: the 2015 International Building Code, the 2015 International Residential Building Code for One- and Two-Family Dwellings, the 2015 National Green Building Standard, the 2015 International Plumbing Code, the 2015 International Property Maintenance Code, the St. Louis County explosives, weights and measures and property maintenance codes, the 2015 International Swimming Pool and Spa Code, the 2014 National Electrical Code, the 2015 International Mechanical Code and the 2015 International Fire Code. No International Energy Conservation Code is on that list. The amendments in Section 500.020 do not delete or amend Chapter 11, Energy Efficiency, of the 2015 IRC, so the residential energy requirements are the ones in that chapter.

Under that edition the required attic value for new work here is R-49, and walls R-20, or R-13 plus R-5 continuous. For comparison, the Department of Energy recommends R60 for an uninsulated attic in this climate zone and R49 where there are already a few inches up there.

Chapter 11 of the 2015 IRC carries the same envelope table as Table R402.1.2 of the 2015 IECC. For climate zone 4 except marine that is ceiling R-49 and wood frame wall R-20 or R-13+5, per the U.S. Department of Energy's 2015 IECC residential provisions summary and the PNNL Building America Solution Center IECC and IRC insulation table.

Do you need a permit to insulate here?

Nothing Ellisville publishes settles this. Its permit lists name the work types it cares about, and insulation is not among them in either direction. That is the normal state of affairs across this metro — only a handful of the 45 jurisdictions on this site say anything about it at all. It says construction documents are reviewed for renovations, additions and new construction. Insulation, air sealing and weatherization are not mentioned. So we ask the department directly before the first day on site, and whatever comes back, pulling it is our job rather than yours.

The city publishes a plumbing license application and Section 500.030 sets out master plumber, apprentice and master drainlayer licensing. Nothing published requires an insulation contractor to register or be licensed with the city.

Permits and inspections in Ellisville

The published number is 636-227-9660. The department page is here.

Permitting is on us, not on you.

Rebates an Ellisville homeowner can actually use

Ellisville is on the Missouri side, which for most addresses means Ameren Missouri — and Ameren Missouri does not hand out a straight per-square-foot insulation rebate the way its Illinois sister utility does. What it runs instead is Pay As You Save: a free home energy assessment, then the work installed by a programme partner and paid back through a fixed monthly charge on the electric bill, which cannot exceed 80% of the estimated monthly saving, so the bill still comes down while it is being repaid. No loan and no credit check.

Published incentives inside that programme for the 2026 programme year are $0.20 per square foot on ceiling and attic insulation, $0.06 per square foot on air sealing, and 50% of costs up to $250 per home on duct sealing. Each one has a condition attached, and they matter:

• Attic: Beginning R-value must be R-20 or below and must be increased to a minimum of R-38. An attic already better than R-20 does not qualify, however much you add to it.
• Air sealing: Must achieve a minimum 20 percent air leakage reduction. That is measured, not asserted, which is why the blower door goes on the door twice.
• Duct sealing: Must achieve a minimum 20 percent duct leakage reduction.
• Who qualifies: the free assessment is open to Ameren Missouri residential electric customers generally, but the incentives above sit inside tier 4 of Pay As You Save and require that you have lived in the home for the past twelve months.

Ameren Missouri also runs CommunitySavers, which installs attic insulation at no charge for income-eligible households. The program operates through December 31, 2026; incentives are dependent on available funds.

Spire, the gas utility on this side, lists furnace, water heater and thermostat rebates on its Missouri rebate page rather than a standalone insulation one. Its published route to attic insulation and air sealing is the same on-bill Pay As You Save programme, which it co-delivers, plus income-based weatherization. If you are a Spire customer it is worth ringing them to ask what is open this year, because that page moves.

If the household income qualifies, the work can be free rather than discounted. St. Louis County is served by Community Action Agency of St. Louis County (CAASTLC) under the Missouri low-income weatherization program — 314-863-0015, details here.

One more, by its absence: the federal 25C credit, which covered 30% of insulation and air sealing up to $1,200 a year, ended for anything placed in service after 31 December 2025. Work finished on or before that date is still claimed on that year's return; nothing done in 2026 is. It should not be in your 2026 price, whoever tells you otherwise — the rebate guide has the detail.

Why the number is what it is

NOAA's 1991–2020 normals put 84.9 nights a year at or below freezing here, and only 19.3 days that never climb back above it. Most freezes in Ellisville thaw the same day, and that daily cycling is what drives moisture into a cold attic. The energy code and rebate guide has the full climate figures.

Nearby

Ellisville borders Clarkson Valley, Ballwin and Wildwood. These are the ones we also cover, each with its own energy code and permit rule:

Elsewhere in St. Louis County we also cover:

How Ellisville compares with the rest of St. Louis County

Missouri sets none of this at state level, so the number that was right one municipality over is not automatically right here.

Common questions about insulation in Ellisville

How much insulation does Ellisville require in an attic?

The code edition Ellisville enforces sets R-49 for new work. The Department of Energy separately recommends R60 for an uninsulated attic in this climate zone, and R49 where a few inches are already there.

Do I need a permit to insulate a house in Ellisville?

Unresolved on paper. Ellisville names the work types it wants permits for and insulation is not one of them, but nor is it on the exemption list. It gets settled by phone before we schedule, at our end.

What insulation rebates can I get in Ellisville?

For most addresses here the route is Ameren Missouri's Pay As You Save programme, which publishes $0.20 per square foot on ceiling and attic insulation and $0.06 per square foot on air sealing for the 2026 programme year. Both carry conditions: the attic has to start at R-20 or below and reach at least R-38, and the air sealing has to cut leakage by at least 20 percent. The incentives sit inside tier 4 of the programme and need you to have lived in the home for the past twelve months, and they are recovered through a monthly charge on the electric bill rather than paid as a cheque. Income-eligible households can get attic insulation at no charge through CommunitySavers instead. The federal 25C credit ended for work placed in service after 31 December 2025.

How old are most houses in Ellisville?

The typical home in Ellisville dates to around the early-1980s. Houses of this vintage usually got batts or blown fibre at whatever the standard of the day was, which is well short of what is recommended now. Most are one top-up away from being right. That figure is an ACS-derived median republished by housing-data services, not a survey of individual houses.

Have you worked in Ellisville before?

Not yet. We have no completed job logged in Ellisville, and we would rather say so than put a number on this page that is not real.

Does Missouri or Illinois license insulation contractors?

Neither state licenses insulation contractors as a trade. In Missouri there is no statewide residential code at all, and registration is imposed city by city — several metro municipalities require a contractor to be registered with them before a permit is pulled. What matters more in practice is utility programme enrolment, because that is what decides whether your rebate is real.

Energy code, permit and department details for Ellisville come from the jurisdiction's own published pages and codified ordinances. Rebate figures come from the utility's own published incentive tables and carry the programme year they were verified in. Housing-age figures are ACS-derived medians republished by housing-data services, so treat them as approximate. Sources: ecode360.com · ecode360.com · ellisville.mo.us · ellisville.mo.us · energycodes.gov · basc.pnnl.gov · data.mo.gov · ellisville.mo.us · en.wikipedia.org · censusreporter.org · point2homes.com · ameren.com · ameren.com · ameren.com · ameren.com · energy.gov. Adopted code editions, department phone numbers and utility rebate amounts all change — confirm with the jurisdiction or the utility before relying on anything here.