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Sizing a furnace for a house in Madison County starts with the structure: insulation, duct layout, how the building sits. 81 severe weather events were recorded in Madison County, Ohio between 2015 and 2024. That rate puts severe weather in the picture without making it the center of every installation decision a contractor works through. What it does mean is that a system installed here has to be set up correctly from the start, because loose ductwork or an undersized unit compounds whatever the seasons bring. A contractor quotes around the house, then confirms the equipment can handle the load this area carries.
Ductwork laid in for older equipment carries assumptions about airflow, trunk sizing, and return placement that a new furnace may not match. Half the homes in Madison County, Ohio were built in 1976 or earlier (2020-2024 ACS 5-year). A contractor quoting a furnace here has to assess what those ducts were built to move and whether the existing runs will distribute heat the way a current unit delivers it. If they will not, the ductwork becomes part of the job before the new equipment is ever ordered.
What Gets Installed With a New Furnace
The furnace itself sits in the basement, utility room, or closet and is the unit that produces heat for the house. Attached to it on the supply side is the plenum, a sheet-metal box that gathers the heated air before it moves into the duct runs. The heat exchanger lives inside the furnace cabinet, separating the combustion gases from the air that enters your living space.
The flue pipe runs from the furnace to an exterior wall or through the roof, carrying combustion exhaust out of the house. The blower motor and its housing sit inside the cabinet as well, pulling return air in and pushing conditioned air out. A new thermostat, mounted on an interior wall, connects to the furnace and tells it when to fire.
The drawing shows a general layout of these components, and a licensed contractor determines exactly what applies to your house.
Get matched in Madison CountyMadison County, Ohio, by the numbers
81 severe weather events were recorded in Madison County, Ohio between 2015 and 2024.
NOAA National Centers for Environmental Information, Storm Events Database, bulk CSV export, events 2015-01-01 through 2024-12-31.Half the homes in Madison County, Ohio were built in 1976 or earlier (2020-2024 ACS 5-year).
U.S. Census Bureau, 2020-2024 American Community Survey 5-Year EstimatesMadison County, Ohio holds 16,519 housing units (2020-2024 ACS 5-year).
U.S. Census Bureau, 2020-2024 American Community Survey 5-Year EstimatesOwners occupy 77.5% of the occupied homes in Madison County, Ohio (2020-2024 ACS 5-year).
U.S. Census Bureau, 2020-2024 American Community Survey 5-Year EstimatesFurnace Installation Rules & Code in Madison County, Ohio18 sourced regulations and standards
What the Installation Actually Looks Like
Non-weatherized gas furnaces manufactured on or after November 19, 2015 must reach 80.0 percent AFUE.
Non-weatherized oil-fired furnaces manufactured on or after November 19, 2015 must reach 83.0 percent AFUE.
Mobile home gas furnaces manufactured on or after November 19, 2015 must reach 80.0 percent AFUE.
Non-weatherized gas furnaces manufactured on or after December 18, 2028 must reach 95.0 percent AFUE, up from the 80.0 percent minimum that applies to units manufactured before that date.
Licensing and Legal Requirements in Madison County, Ohio
An Ohio home construction services contract must include a copy of the supplier's certificate of insurance showing general liability coverage of not less than two hundred fifty thousand dollars.
In Ohio a home construction service means the construction of a residential building, including the repair, improvement, remodel or renovation of an existing structure, and does not include construction on a structure containing four or more dwelling units except for work on an individual dwelling unit within it.
A home construction service supplier in Ohio is defined as a person who contracts with an owner to provide home construction services for compensation and who maintains a general liability insurance policy of not less than two hundred fifty thousand dollars.
The Ohio construction industry licensing board issues state licenses to individuals as heating, ventilating and air conditioning contractors, refrigeration contractors, electrical contractors, plumbing contractors and hydronics contractors.
An Ohio board of county commissioners may accept a valid and unexpired Chapter 4740 license held by a heating, ventilating and air conditioning contractor toward its own licensing requirements for work on one-, two-, or three-family dwelling houses.
An Ohio board of county commissioners may adopt rules licensing heating, ventilating and air conditioning contractors who are not required to hold a state license under Chapter 4740.
In Ohio municipal law a specialty contractor includes heating, ventilating and air conditioning contractors, refrigeration contractors, electrical contractors, plumbing contractors and hydronics contractors.
An Ohio board of county commissioners may not register a specialty contractor who is required to hold a license under Chapter 4740 but does not hold a valid one.
An Ohio municipal corporation may not register a specialty contractor who is required to hold a license under Chapter 4740 but does not hold a valid one.
In Ohio building law a residential building means a one-family, two-family or three-family dwelling house and any accessory structure incidental to it, and does not include an industrialized unit, a manufactured home or a mobile home.
Ohio's contractor licensing chapter reaches only work on a construction project, and a construction project is defined to exclude residential buildings, so an HVAC contractor working on a one-, two-, or three-family dwelling in Ohio falls outside the state licensing requirement.
Violating Ohio's contractor licensing prohibition is a minor misdemeanor on a first violation and a misdemeanor of the fourth degree on subsequent violations.
Under Ohio law no person may act as or claim to be a type of contractor that Chapter 4740 licenses unless that person holds a license issued under that chapter.
In Ohio a home construction service supplier may not perform a home construction service costing twenty-five thousand dollars or more without entering into a written home construction services contract with the owner, unless the supplier and owner enter into a cost-plus contract.
Severe Weather History in Madison County
Heating equipment in Ohio works against whatever the local climate throws at it, and Madison County's weather record is part of what shapes how hard a furnace has to work over its lifetime. Contractors who install here account for that workload when they size and spec equipment.
81 severe weather events, 2015–2024. Source: NOAA National Centers for Environmental Information, Storm Events Database.