This is St. Louis's heating and cooling page, built from St. Louis's own numbers: Census housing figures, the metro's ZIP codes and its NOAA climate record. TempReach USA routes your call to an independent local HVAC technician; the homework below is here so you know your home's likely problems before you ever make it.
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The median St. Louis home was built in 1973; 58.8% of the stock predates 1980, and the pattern this metro's own data ranks first is the refrigerant transition reaching older systems. TempReach USA is a referral service, not an HVAC company: one call connects you with an independent local HVAC technician serving your ZIP code.
Read St. Louis through its counties and the picture sharpens. Bond, Calhoun, Clinton, Jersey, Macoupin, Madison, Monroe, St. Clair, Franklin, Jefferson, Lincoln, St. Charles, St. Louis, Warren, St. Louis city were not built in the same decades or for the same households, and their heating and cooling carries those differences: an older core where 33.8% of the metro's homes predate 1960, growth corridors where the subdivisions arrived in waves, and edges still being built out. The metro-wide medians — a middle home built in 1973, 1,267,353 housing units in all — are the average of those local stories, and the sections below are organised by the patterns the combined record produces, from the oldest equipment generations to the newest failure modes.
The pre-1980 stock is where most of the metro's HVAC character lives. Homes from those decades in Bond County and across Bond, Calhoun, Clinton, Jersey, Macoupin, Madison, Monroe, St. Clair, Franklin, Jefferson, Lincoln, St. Charles, St. Louis, Warren, St. Louis city were built with duct layouts from the first age of central systems, furnaces and condensers that have since been renewed piecemeal, and insulation standards from another era, and each of those choices is now at or beyond the age its makers expected of it. Owner-occupiers hold 70.1% of the metro's homes, so most of the people reading this page are reading about a system they own outright — one whose failures arrive as surprises only if nobody has looked at the pattern: cooling fading a little each summer, a furnace recovering a little more slowly, one room drifting a little further from the thermostat.
The newer side of St. Louis — the 18.5% of homes built since 2000, concentrated around growing communities like St. Louis — runs on matched modern systems that age more gracefully but fail in their own ways: heat pumps and condensers worked hard by 1,713 cooling degree days of hot-season demand, control boards and sensors wearing out in houses that all reach the same age at the same time. One metro, two equipment generations, and the sections below take them in the order this metro's data ranks them.
Over everything sits the weather, and here it is measured rather than described: NOAA's station at ST LOUIS LAMBERT INTL AP, MO US averages 57.4 degrees across the year, with 47.1 days reaching 90 or more and 84.9 nights at freezing or below. A furnace feels that record as a season of relentless cycling; a condenser feels it as a summer without a quiet week; a heat pump feels both. The problem ranking below is what those numbers, crossed with the housing profile, produce for St. Louis specifically.
The metro's building eras on one side, its weather record on the other — and its heating and cooling where the two meet.
Lay the eras side by side instead: 33.8% pre-1960 (428,365 homes), 25.0% from 1960-1979 (316,838), 22.7% from 1980-1999 (287,689), and 18.5% since 2000 (234,460). No single era tells the story — the proportions among them do, and those proportions are different in every metro this site covers.
Some metros are defined by their growth; this one is defined by its inheritance. The largest share of St. Louis's homes was built before 1960, and inheritance in HVAC means system designs from another era serving households who did not choose them. The work that follows from that fact is the metro's staple: furnaces renewed, condensers renewed, ducts sealed and rebalanced — the patient, house-by-house modernisation of a founding stock. Newer districts exist and matter, but they are not where this metro's HVAC character was decided.
Close behind the leader come the 1960-1979 homes, 25.0% of the stock. Their systems are mid-change by construction — the decades when cooling spread mid-stream — so this band is where a St. Louis technician earns the diagnostic fee: airflow readings and pressure tests that say which side of the transition a given house was built on.
St. Louis's weather, reduced to what a system experiences: 47.1 hot days a year loading the cooling, 84.9 freezing nights loading the heating, and 41.7 inches of rain feeding the humidity both seasons complain about. NOAA's normals at ST LOUIS LAMBERT INTL AP, MO US — 4,433 heating degree days, 1,713 cooling degree days — are the long average of that experience, and they are why this metro's problem list is not interchangeable with a milder or harsher metro's.
Hold the two halves together and the rest of this page explains itself: the problems ranked highest here are the ones where St. Louis's dominant housing era and its climate record overlap. Change either dataset and the ranking changes — which is precisely why this profile is rebuilt from the records for every metro instead of carried over from the last one.
Sequenced by this metro's own problem ranking, not by a national catalogue order.
The local professional you are connected with reads the system the way it fails: electrical values first, then temperatures and pressures, then airflow, until one finding explains all of the symptoms at once.
One more pattern belongs in the St. Louis picture: repair calls here are also a refrigerant story. Systems fitted in the older decades run on refrigerant generations the industry has been retiring, and every repair on those units weighs the charge's scarcity against the system's remaining life. The technician who explains that arithmetic plainly — what the repair restores, what it cannot assure anyone about next summer — is giving the household the real choice, and in the 745,204 pre-1980 homes it is a conversation held weekly. That is the daily reality for the 1,154,841 households spread across Bond, Calhoun, Clinton, Jersey, Macoupin, Madison, Monroe, St. Clair, Franklin, Jefferson, Lincoln, St. Charles, St. Louis, Warren, St. Louis city.
The local caseload behind this service is written in the climate figures: 1,713 cooling degree days a year and 47.1 days at 90 or above, pressing on a cooling fleet whose oldest members serve the 745,204 pre-1980 homes — in O'Fallon (92,697 residents) as much as in the oldest districts.
In St. Louis this service is booked most often through the problem patterns at the top of this page — the metro's housing data, not habit, sets the order. If your home is in the 58.8% built before 1980, mention its age on the call: it changes the parts the technician loads before heading to St. Louis and the rest of the metro.
Post-renovation is the clearest case in the trade. Drywall dust and sanding residue settle through every open register, and one thorough cleaning after the work ends removes in hours what the system would otherwise circulate for years.
Ducts in St. Louis collect what the metro's life sends through them: construction dust in the growth subdivisions, decades of household dust in the older districts, pollen riding the return air through long pollen seasons. The honest framing for cleaning is the system's condition, not a calendar — a duct system in a the 1970s home that has been remodelled twice carries a different load from one in a new build near O'Fallon. The cleaning visit itself is agitation and extraction under negative pressure, register by register, with the blower compartment and coil inspected while access is open. Locally the workload concentrates where the stock is oldest — the districts built around the 1970s first.
Duct demand concentrates in the metro's long-biography homes: 745,204 pre-1980 systems that have carried decades of household air, and the renovated homes around St. Peters (58,200 residents) whose construction dust is still in the runs.
Where this service gets booked in St. Louis follows the map on this page: the older districts generate the deep-end work, the post-2000 subdivisions the wear-and-tear work, and the 287,689 homes in between split the difference. Telling the call center your home's build decade — most St. Louis owners know it within a few years — puts the right kit on the van the first time.
The condition report is the product that outlasts the visit. Specific measurements, watch items named, urgency ranked — and next year's visit comparing against this year's numbers, so drift becomes visible before it becomes failure.
Ask what a tune-up prevents in St. Louis and the answer is the peak-season failure: the capacitor that gives out on the first 100-degree afternoon, the condensate switch that floods a closet in the humid weeks, the igniter that chooses the coldest night of January. Those parts announce themselves in advance to anyone measuring — weakening values, slow drains, dirty flame sensors — and the maintenance visit exists to hear the announcements in spring and autumn instead of in the emergency weeks. In St. Louis that holds across 241 ZIP codes, from St. Louis out to St. Charles.
The maintenance caseload is the installed base itself: 1,267,353 housing units whose systems each face 47.1 hot days and 84.9 freezing nights a year. Around Chesterfield (49,591 residents) as in the old core, the twice-yearly visit is what stands between that calendar and the emergency diary.
One local habit worth copying: St. Louis homeowners who mention their street's building era when they book get a better-matched visit, because a technician heading to a the 1970s home in Bond County loads different parts than one heading to a new-build subdivision in O'Fallon. The service is the same; the preparation is local.
A furnace announces its fault by where its startup sequence stops — inducer, ignition, flame proving or blower — and St. Louis technicians diagnose by watching that sequence, not by replacing parts in a hopeful order.
A furnace in St. Louis rarely fails all at once; it files warnings first. Short cycling on cold mornings, a rumble at startup, one room that never reaches the thermostat's number while the rest of the house overshoots. The metro's climate makes those warnings worth reading early — a system that limps in October is being examined by 84.9 freezing nights all winter. The repair visit tests the safety chain before anything else: the exchanger's integrity, the venting, the carbon monoxide picture, then the parts that wear. Count it in homes if you prefer: 745,204 built before 1980, 234,460 since 2000, one shared system of streets and seasons.
Heating demand in St. Louis concentrates where the cold does its work: 84.9 nights a year at or below freezing, against a housing stock whose median build year is 1973. Around Belleville as in the old core, that combination is not an abstraction — it is the street's furnaces, house by house.
One local habit worth copying: St. Louis homeowners who mention their street's building era when they book get a better-matched visit, because a technician heading to a the 1970s home in Bond County loads different parts than one heading to a new-build subdivision in O'Fallon. The service is the same; the preparation is local.
Stabilization precedes diagnosis. The fault isolated, the water contained, the dangerous component out of service — a repair decided in a worsening house is rarely the right one, so the worsening stops first.
What counts as an emergency here is narrower than discomfort and wider than breakdown. No cooling with an infant or an elderly resident in the house during a St. Louis heat stretch is an emergency. No heat with pipes exposed to a freezing night is an emergency twice over. A burning smell, a tripped breaker that will not hold, water from a condensate overflow — each is the system asking for a same-day answer. The call center's questions sort the urgent from the schedulable, and local technicians already working these streets are the ones routed first. The 41.7 inches of rain in an average year here is part of the story too — humidity loads every cooling coil in the metro.
Scale the problem by the Census count: 1,154,841 households depending on systems that cannot be improvised around — no heat in a freeze, no cooling in a heat wave. The emergency visit exists for the hours when waiting until Monday is not a plan, in Oakville this month, somewhere else next.
In St. Louis this service is booked most often through the problem patterns at the top of this page — the metro's housing data, not habit, sets the order. If your home is in the 58.8% built before 1980, mention its age on the call: it changes the parts the technician loads before heading to St. Louis and the rest of the metro.
From St. Louis to St. Peters, St. Louis replacements routed through TempReach USA end in commissioning — measured charge and airflow — so the installed system matches the calculated one.
From St. Louis to St. Peters, St. Louis installations routed through TempReach USA finish with commissioning — combustion, temperature rise and airflow verified — so the fitted system is the specified system.
Across 241 ZIP codes and housing from a median build year of 1973, St. Louis heat pumps are specified and serviced from heat-loss figures and low-temperature performance data, not nominal tonnage.
From period homes near St. Louis to newer builds toward St. Peters, St. Louis's ductless projects serve the rooms central systems miss — additions, conversions and homes built without ductwork.
Across Bond, Calhoun, Clinton, Jersey, Macoupin, Madison, Monroe, St. Clair, Franklin, Jefferson, Lincoln, St. Charles, St. Louis, Warren, St. Louis city, the housing split decides the starting point: older, leakier homes around St. Louis usually need filtration and moisture work first, while tighter newer builds in the 241 covered ZIP codes usually need deliberate ventilation most.
In St. Louis, the thermostat question splits by housing era: homes from around the median build year of 1973 often lack a common wire in the wall, while newer builds across the 241 covered ZIP codes usually carry one — the local professional checks the cable before choosing the control.
St. Louis's commercial buildings span every era around a median build year of 1973 — and with the era goes the equipment, from aging single units over old storefronts to multi-zone systems in new developments, all serviced from a per-unit record.
If this page's services were ranked by St. Louis's call patterns rather than listed in catalogue order, they would come out much as they do here — because the ranking behind them is data, not habit. The refrigerant transition reaching older systems leads the metro's problem table and leaky ducts losing air and energy follows, so the services answering them lead the list. The long tail of a metro's HVAC life — thermostat calls, duct questions, the one room that never matches the rest — fills in the diary around them, here as everywhere.
Selected and ranked from this metro's housing-age profile and climate record — not copied from another city's page.
There is a paperwork side to the transition that touches St. Louis homes quietly. Refrigerant work is regulated work: recovery, handling and record-keeping rules apply to whoever services a system, and the newest refrigerants — mildly flammable by classification — arrive with their own sensors, labeling and code provisions that installers must follow. For the homeowner the visible part is small: a nameplate with a different designation, a technician explaining why a charge is measured and documented as it is, an installation that includes leak-detection provisions the older system never had. The invisible part matters more over time: as the newest generation becomes the metro's standard, parts, training and service practice consolidate around it, and the older generations become the specialty work. Owning an older-generation system is not a fault — but its service ecosystem is, year by year, becoming a smaller room.
Judge a refrigerant-era system by its leak history and its trend, not by a single charge reading. One low reading after many tight years is an event; a pattern of small losses is a biography, and the biography is what the economics should be based on. St. Louis's climate record loads the question at both ends — a leaking system underperforms exactly when ST LOUIS LAMBERT INTL AP, MO US's 47.1 hot days demand its full capacity, and its owner pays for refrigerant and lost performance simultaneously. The households that navigate this transition well keep one habit: they can state their system's age, refrigerant and last three repairs without looking them up. That small command of the facts converts an industry-wide generational change into a single household's managed decision, which is the scale at which it was always going to be decided anyway.
Count the generations the way a technician's route does: a single St. Louis street can hold an R-22 veteran, two R-410A systems and a current-generation installation within a few doors. The service records of one metro contain the whole transition — which is why identification, not assumption, opens every diagnosis here.
Renovation writes its own chapter in this pattern. Homes in St. Louis have been extended, finished and re-divided for decades — a garage converted, a basement finished, an addition tied into ductwork sized for the original house. Each alteration borrows air from the existing network, and the borrowing is rarely repaid with new capacity or rebalanced runs. The result is a duct system whose map no longer matches the house it serves: original rooms over-supplied, added rooms fed by a hopeful tap into a trunk that was never asked to carry them. Add the slow leaks of age on top of the redesigns of renovation, and the far rooms' complaints stop being mysterious. The remedy starts with honesty about the map — what was designed, what was improvised, and what each run can actually deliver — before any cleaning, sealing or resizing is worth doing.
Households judge their heating and cooling at the thermostat, but the thermostat only reports the room it sits in. Judge the system at its furthest register instead: the air arriving there, its temperature against the supply at the unit, its volume against the room's need. In St. Louis that furthest room is the honest auditor of the duct network — it inherits every leak, every sag and every degree of attic heat between it and the air handler. The homes whose far rooms match their near rooms have networks that were sealed when they were built and checked as they aged. The homes whose far rooms lag are not necessarily homes with weak equipment; they are homes whose delivery network has been quietly resigning, joint by joint, while the equipment took the blame and the service calls. The register, not the nameplate, is where the resignation is announced.
The housing numbers frame the exposure: 1,267,353 housing units in St. Louis, a median build year of 1973, and duct networks installed era by era in attics, crawl spaces and wall cavities. Every one of those networks is a set of joints ageing in the dark — the loss pool is the size of the metro itself.
Ageing also changes what a repair means. On a young system, a failed part is an interruption; on an old one, it is information — a data point about the machine's remaining life and about whether the next failure is already loading. In the older districts of St. Louis, around St. Louis and the streets that grew with it, technicians read repairs that way and say so: this motor can be replaced, and here is what its failure tells us about the compressor behind it. The household's decision — maintain, repair, or plan a replacement on a calm schedule — is only as good as that reading. Systems do not owe anyone a warning before their last season, but in practice they file their intentions in a language of rising run times and narrowing margins, for those who have the readings taken.
Judge an ageing system by its trend line, never by its kindest day. On its kindest day — mild weather, light load — almost any system in St. Louis can still argue for itself. The trend line is written elsewhere: in run times lengthening season over season, in the setting creeping to hold the same comfort, in the rooms that quietly dropped out of the system's reach. ST LOUIS LAMBERT INTL AP, MO US's climate record ensures the trend will be tested at both ends of the year — 47.1 hot days and 84.9 freezing nights in an average year. The households that read their trend early choose the terms of the ending, whether that ending is a renewed component, a planned replacement in a shoulder season, or a few more good years bought with honest maintenance. The households that wait for the system's verdict receive it in the weather least suited to hearing it.
The arithmetic is straightforward: 1,267,353 housing units in St. Louis, a median build year of 1973, and equipment that turns over far more slowly than it ages. At any given moment, a large share of the metro's systems are in the second half of their working lives — being maintained there, or being discovered there.
Ask a furnace what hard cold does to it and it answers in cycles. Every call for heat is a sequence — inducer, igniter, gas valve, flame proving, blower — and deep cold multiplies the sequences while lengthening each run. In St. Louis the oldest furnaces run that sequence in the oldest housing: the 745,204 pre-1980 homes across the metro, whose flues, ductwork and clearances were built for earlier generations of equipment. A replacement furnace in such a home inherits the harder half of the installation — the venting and duct conditions — while the furnace being retired often shows the season's wear in its heat exchanger and its ignition train. Reading that wear correctly, rather than replacing parts one failure at a time, is the judgment the cold season asks of both homeowner and technician.
Judge a furnace by its coldest week, not its kindest. In its coldest week a St. Louis furnace shows its true condition: whether it lights first time every time, whether it holds the house through the night without the temperature sagging, whether its sounds are the sounds it made when it was younger. ST LOUIS LAMBERT INTL AP, MO US's record — 84.9 freezing nights in an average year — makes the examination annual and unsparing. Households that come through it without drama have usually done one unglamorous thing: they treated the autumn symptoms as the season's advance copy. A furnace rarely fails without having filed its intentions first, in a slower start, a louder cycle, a room that stopped keeping up. The winter merely publishes what the furnace had already written.
Housing adds its evidence: with a median build year of 1973, much of St. Louis's heating plant serves homes whose ductwork and insulation ask more per cold night than modern construction would. The furnace wears against the house as well as the weather.
A heating failure in mild weather is an appointment. The same failure in a hard freeze is a countdown, because a house without heat in St. Louis's coldest weather is losing temperature toward the point where its plumbing becomes the next casualty. The record at ST LOUIS LAMBERT INTL AP, MO US — 84.9 nights a year at or below freezing and 4,433 heating degree days across the season — says the exposure is not hypothetical here. As indoor temperature falls, the spaces that go first are the ones the heat reached last: pipes in exterior walls, runs through crawl spaces and garages, the plumbing of additions and rooms over unheated ground. A burst pipe discovered at the thaw converts one breakdown into two trades' worth of damage, which is why freeze-season heating calls run on different logic from every other call of the year: restore heat or protect the house, in that order, with no step treated as routine. Knowing the sequence before the night it is needed — how to keep a house safer while help travels, when to drip taps, when to shut water down — is part of owning a heated home in this climate.
A freeze-call diagnosis runs triage first and depth second. The first questions sort the stop into its great families: no power or no call for heat; a safety lockout reporting itself through the board's codes; a fuel or ignition failure; a condensate or venting stop on high-efficiency equipment; a heat pump standing on failed auxiliary heat. Each family has a different restoration path and a different implication for how long the house will be cold. In the same visit, the freeze-specific checks ride along: the condensate drain's exposed run, the intake and exhaust terminations against snow and ice, the state of the spaces the pipes cross. Where restoration will take time, the professional's advice turns to the house itself — which water to shut, which taps to open, which rooms to close off and consolidate warmth in — because in a freeze the building is the second patient, and its treatment window is shorter than the equipment's.
The timing evidence recurs every cold season: heating calls in St. Louis cluster in the deepest cold and at the thaw, the signature of marginal systems audited simultaneously by 47.1-degree summers' opposite number — the freeze weeks when ST LOUIS LAMBERT INTL AP, MO US's coldest readings arrive together.
Twice a year, St. Louis changes its mind. The shoulder seasons — the weeks when a house can need heating in the morning and cooling by afternoon, sometimes within the same day — ask more of a system and its household than either deep season does: both modes in working order at once, controls set for change rather than for a settled pattern, and equipment that may sit idle for stretches and then be called on without ceremony. The record at ST LOUIS LAMBERT INTL AP, MO US frames the workload honestly — 4,433 heating degree days against 1,713 cooling degree days, a genuinely two-season climate — and the shoulders are where the two halves meet and negotiate. The checks that matter are changeover checks: the season just ending reviewed for what it spent — the filter, the wear items, the symptoms it filed — and the season arriving proven before it is needed, with a full run in the new mode while the weather is still forgiving. The thermostat's program belongs in the same check; last season's schedule, carried forward unexamined, is how a house ends up heating against an open-window afternoon. Households that treat the shoulders as their maintenance seasons get two calm, well-timed looks at their system a year — which is exactly the rhythm the equipment's manufacturers had in mind.
The season loads St. Louis's systems the way its record at ST LOUIS LAMBERT INTL AP, MO US says it will: 4,433 heating degree days against 1,713 cooling degree days in an average year, against a housing stock whose median build year is 1973. The households that read the season early — filters, drains, a system run before the extreme weeks — are the ones whose calls stay schedulable.
There is a supply-side depth as well. A shrinking refrigerant does not vanish; it circulates — recovered from retired systems, reclaimed to specification, and returned to service at an expense that reflects the shrinking pool. In St. Louis that means the R-22 in a system serviced this year may have cooled three other homes before it, and may cool another after this system retires, provided it is recovered rather than vented. The chain gives older equipment a managed twilight rather than a cliff: service remains possible, performed by technicians qualified for the work, for as long as the economics hold for the household. Understanding that chain replaces two common errors — that old systems are already unserviceable, and that they can be serviced forever as cheaply as ever — with the true picture: a gradually tightening supply, a gradually aging fleet, and a decision that improves with information and worsens with delay.
Read the ranking backwards and it reads as a data summary: 2,809,414 residents in 1,267,353 housing units, 33.8% of the housing from before 1960, 41.7 inches of rain in an average year. The pattern leads because the exposure is broad — counted not in individual unlucky houses but in whole eras of the metro's building, stacked one on another.
The first visit follows a short, diagnostic list — each item ruling a branch of the problem in or out:
PROBLEM
SOLUTIONPopulation 293,109
Population 92,697
Population 71,048
Population 58,200
Population 51,915
Population 49,591
Population 45,734
Population 41,722
Population 35,168
Population 35,166
Population 34,655
Population 30,835
Also in the St. Louis metro: Kirkwood (population 29,302), Mehlville (population 29,089).
Read the grid as a building programme spread over a century. The oldest communities sit where the metro began; the youngest are still adding streets at its edge; and O'Fallon and St. Charles, with 92,697 and 71,048 residents, stand for the rings in between. Each ring was fitted in its era's equipment, and each is now failing, wearing or holding in its era's characteristic order. The ZIP codes below draw the coverage boundary; the eras inside it draw everything else on this page — the problems ranked, the services ordered, the checks advised.
The map continues: St. Peters (58,200), Florissant (51,915), Chesterfield (49,591), Wentzville (45,734), Belleville (41,722). Different names, different decades — each community in Bond, Calhoun, Clinton, Jersey, Macoupin, Madison, Monroe, St. Clair, Franklin, Jefferson, Lincoln, St. Charles, St. Louis, Warren, St. Louis city was fitted with heating and cooling in its own growth years, which is why two streets in the same metro can need entirely different HVAC conversations. The ZIP list below is the working definition of coverage; the housing behind each code is the working definition of the job.
St. Louis (293,109 residents) anchors the metro, and O'Fallon (92,697) is its second centre of gravity. Between them they hold the bulk of the 1,154,841 households — and, not coincidentally, the bulk of every housing era this page discusses, from the pre-1960 core to the newest subdivisions. St. Charles (71,048) and the communities beyond it repeat the same eras at smaller scale.
Administratively the metro is drawn from Bond, Calhoun, Clinton, Jersey, Macoupin, Madison, Monroe, St. Clair, Franklin, Jefferson, Lincoln, St. Charles, St. Louis, Warren, St. Louis city — 15 in all — with Bond County at its centre. County lines do not change how a system runs, but they do shape the paperwork around the work: permits, inspections and code details are county and city business, which is one reason the professional who serves your street is a local one.
Three neighbouring coverage areas begin where this one ends: Jefferson City, MO, some 99 miles off; Columbia, MO, 124 miles; and Springfield, MO, 182 miles. Each keeps its own page because each keeps its own numbers — a different median build year, a different climate station, a different problem ranking. Boundary households should trust the ZIP list over the map: the code, not the compass, assigns the dataset.
Set St. Louis among its neighbours and the contrasts sharpen the profile: Jefferson City, MO — metro population 152,712, median build year 1982 — sits 99 miles away; Columbia, MO (219,062, median 1990) 124 miles; Springfield, MO (500,694, median 1987) 182 miles. Three different housing stocks under three nearby skies, which is why each keeps its own page and its own problem ranking rather than borrowing this one.
Ratios tell the metro's story compactly. Renters occupy 29.9% of homes; owners hold the rest. For every home built since 2000 there are 3.2 from before 1980. Spread the stock across the coverage map and each ZIP code carries about 5,259 housing units — the density at which era patterns repeat street after street instead of scattering, and at which a routed round of calls stays inside a few districts.
The St. Louis record in one line — median home age: 53 years · owner-occupied homes: 809,544 · renter-occupied homes: 345,297 · pre-1960 homes per covered ZIP code: 1,777 · heating-to-cooling degree-day ratio: 2.59 · average rainfall: 1,059 mm a year.
County pages carry the local detail — land area, climate normals and the heating and cooling pressures on the ground in each county.
More plain-language help: the TempReach USA heating & cooling guides
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