Central Iowa heats mostly with natural gas at the metro core, but the state's full heating ledger is wider and more expensive than the gas map suggests. Propane trucks serve an enormous share of rural Iowa, from the small towns of the carve out past every gas main, and oil furnaces survive in older farmhouses. Electric baseboard hides in student-adjacent conversions near Drake and in Ames, and in additions across the older neighborhoods. Aging first-generation heat pumps in the newer suburbs quietly burn resistance-strip money through every below-zero stretch. This guide runs the conversion arithmetic for each case, with a long Iowa winter doing the multiplying.
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 multiple efficiency | Strong |
| Propane | Usually rural Iowa'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 past the gas mains, and rural Iowa is defined by being past the gas mains, buys heat in large lumps, a tank fill at a time, at prices that swing with a market it cannot negotiate with. Several hundred gallons of propane a winter is ordinary when the heating season runs from October into April. A cold-climate 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 MidAmerican rebate tiers trim 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 of a long season. 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 the metro's rental and conversion stock, the student blocks of Ames and the Drake Neighborhood, older houses cut into flats in Sherman Hill and Highland Park Des Moines, this is the most common expensive-heat configuration and the strongest case in this guide. The long 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, Ankeny, Waukee, Johnston, Urbandale, 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 central Iowa's real design days, they hand the load to electric resistance backup at full resistance rates, precisely when the cold makes the load largest. The bill signature is unmistakable: tolerable shoulder months, brutal deep-winter statements. A modern cold-climate variable-speed replacement, specified against published capacity tables per 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 stretches 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 Iowa, 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 propane, oil, and resistance conversions the year wins by a margin the rebate only sweetens.
Renters, Landlords, and the Split Incentive
The metro's most expensive heat disproportionately warms people who cannot replace the equipment: baseboard in Drake-adjacent conversions and Ames rentals, tired systems in the older blocks, resistance additions across the prewar 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 rebated purchase through MidAmerican's tiers, 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.
One Rule Before Any Conversion
Every case above assumes the machine was specified for central Iowa's real winter: published capacity at the design condition beside a room-by-room load calculation, cold-climate equipment, 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 after the first below-zero stretch. Skip it and the strips will quietly re-run these numbers in the other direction.
The Short Version
Propane and oil lose to the heat pump on truck-versus-meter arithmetic, and propane loses hardest. 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, Iowa nice has nothing to do with it, and the rebate arrives at the register.
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