South Central Wisconsin heats mostly with natural gas at its metro core, but the region's full heating ledger is messier and more expensive than the gas map suggests. Propane and oil trucks still serve the rural townships across the carve, from the Driftless edges out past the Dells country. Electric baseboard hides in older conversions near the Isthmus, student-adjacent flats, and additions across the Near East and Near West Sides. And aging heat pumps in the newer suburbs quietly burn resistance-strip money through every below-zero stretch. This guide runs the conversion arithmetic for each, including the honest gas paragraph that sales pages skip.
The Ledger in One Table
| Existing heat | Case for a heat pump | Strength |
|---|---|---|
| Heating oil | Truck-priced fuel loses to metered kilowatt hours moved at two to three times efficiency | Strong |
| Propane | Usually the region's most expensive delivered heat | Strongest |
| Electric resistance | Same meter, a half to a third the consumption for the same warmth | Strongest |
| Aging heat pump | Modern cold-climate machine holds capacity below zero, retires the strips | Strong |
| Natural gas | Closest race; usually decided at equipment end of life | Honest maybe |
Delivered Fuel: The Truck Stops Coming
A household buying propane or oil pays for heat in large lumps, a tank fill at a time, at prices that swing with a market it cannot negotiate with. Several hundred gallons a winter is ordinary in the carve's rural stretches, where the heating season runs long and the gas mains never arrived. A heat pump replaces those gallons with kilowatt hours that move two to three units of heat per unit of electricity, billed monthly at rates that move slowly. The saving shows up in four figures for most conversions, and its shape is distinctive: the delivery line disappears entirely, the winter electric bill rises, and the year-total falls. These are the fastest-payback whole-home projects in the region, priced in our installation cost guide, and the Focus on Energy instant discount, $400 to $900 off qualifying equipment, trims the front end at purchase.
Electric Resistance: Arithmetic on a Single Bill
Resistance heat, baseboard, ceiling cable, wall units, converts one unit of electricity into one unit of warmth, full price, every hour. A heat pump on the same meter at the same rate moves two to three units of warmth per unit purchased. No fuel forecast, no rate speculation, no assumptions: the same bill simply shrinks toward a half or a third for the heating share. In Madison's rental and conversion stock, older houses cut into flats decades ago, this is the most common expensive-heat configuration, and it is the strongest conversion case in this guide. The long Wisconsin heating season sharpens it: the more hours the multiplier works, the larger the annual number it produces.
The Aging Heat Pump, the Quiet Money Leak
The newer suburbs, Fitchburg, Sun Prairie, Verona, Waunakee, hold earlier-generation heat pumps that were honest machines in their day and are strip-heaters in this one. Below the temperatures where their compressors fade, well above this region's design nights, they hand the load to electric resistance backup, which bills at full resistance rates precisely when the cold makes the load largest. The bill signature is unmistakable: tolerable shoulder months, brutal deep-winter stretches. A modern cold-climate variable-speed replacement, specified against published capacity tables in our cold-weather guide, holds output far deeper into the cold and retires the strip habit. Owners see similar bills in mild months and meaningfully lower ones in the deep stretches, exactly where the old machine was bleeding.
The Honest Gas Paragraph
A household with a functioning furnace on the metro's gas grid faces the closest race in the region, and deserves it stated coldly. Gas is cheap heat in Wisconsin, and displacing a mid-life furnace rarely pays on fuel savings alone. The conversion cases that clear anyway are calendar cases: the furnace at end of life, where the replacement dollar was being spent regardless; the air conditioner also due, since one machine replaces both; the household that wants off combustion for its own reasons and prices that preference honestly. Dual fuel, a heat pump carrying the season with the furnace held for the deepest below-zero nights, is a legitimate configuration a good contractor prices without being asked. What no honest bidder does is promise a gas household dramatic savings; a bid that does has failed the first test in our contractor guide.
Reading the First Winter Correctly
Judge the conversion by shape, not by a single statement. The delivered-fuel convert sees a larger winter electric bill and a smaller year, because the truck line vanished. The resistance convert sees the same warmth cheaper immediately. The heat pump replacer sees the deep stretches flatten. The discipline that makes all three legible is one ledger: last year's total heating spend, every source, next to this year's, read whole year against whole year each spring. January in isolation is always the wrong number; in a below-zero climate it is the most misleading number in the file. The year is the verdict, and for oil, propane, and resistance conversions the year wins by a margin the instant discount only sweetens.
Renters, Landlords, and the Split Incentive
The region's most expensive heat disproportionately warms people who cannot replace the equipment: baseboard in Isthmus-adjacent conversions, tired systems in student-heavy blocks, resistance additions across the older neighborhoods. The tenant pays the bill; the owner owns the fix; and the arithmetic in this guide reads identically for both, with only the beneficiary line changing. The owner's case needs no subsidy: a discounted purchase through Focus on Energy, a large operating improvement, real summer cooling in stock that never had it, and a winter bill a tenant can pay. A tenant's cheapest and most effective move is forwarding this page to whoever holds the deed, with one sentence attached: the heating system is costing us both money.
The Cooling Dividend, Counted Once
Most of the stock this guide's strongest cases live in, rural farmhouses on propane, Isthmus-adjacent conversions on baseboard, has never had central air conditioning, and Wisconsin summers have stopped pretending it is unnecessary. The same machine that retires the truck or the baseboard cools the house in July, which means the conversion price is buying two systems and the comparison ledger should say so. Count it once, honestly, as avoided air conditioner spend, and the payback math in every case above improves without a single assumption changing.
One Rule Before Any Conversion
Every case above assumes the machine was specified for this region's actual below-zero design nights: published capacity at the design condition beside a room-by-room load calculation, backup sized as a safety net rather than a crutch. The arithmetic in this guide is fuel arithmetic; the specification discipline is what keeps it true through the first deep stretch. A conversion that skips it can turn the strongest case on this page into a strip-heat bill wearing a new nameplate.
The Short Version
Propane and oil lose to the heat pump on truck-versus-meter arithmetic. Resistance loses on a single bill's multiplication, loudest in a long heating season. Aging heat pumps lose on their strip habit through every below-zero stretch. Functioning gas furnaces make it a fair fight the calendar usually settles. The math carries every case, and the statewide instant discount arrives at the register rather than in the mail.
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