Propane vs Natural Gas for Your Home: Cost, Safety, Setup

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Propane and natural gas both heat homes, water and cooking appliances well, and for most households the choice is made by geography. If a natural gas main runs down your street, natural gas is usually cheaper to run and needs no tank or delivery schedule. If it does not, propane is the practical fuel for a gas furnace, range or water heater, at a higher typical cost per unit of heat. Propane carries more energy per cubic foot, but it is sold by the gallon from a tank on your property, and it behaves differently in a leak because it is heavier than air. This guide compares the two side by side, walks through a cost-per-therm example, covers conversion, safety, Front Range altitude and cold-weather factors, and explains what an inspector checks on either system. It summarizes general guidance as of 2026; your appliance manuals, fuel supplier and local building department take priority for any specific installation.

Part of our Heating, Cooling & Ventilation guide — start there for the full picture →

Quick Verdict and Side-by-Side Comparison

Choose natural gas if a utility line is available at a reasonable hookup cost: it is typically cheaper per unit of heat, flows continuously and needs no tank. Choose propane if you are in a rural, foothills or eastern-plains area without a gas main, want gas cooking or heat in a home that is otherwise all-electric, or need fuel for a standby generator, outdoor kitchen or fireplace where piping natural gas is impractical.

Costs above are typical national ranges, 2026; propane tank pricing and utility line-extension charges vary widely by supplier, distance and site. Get written quotes from your utility and at least two propane suppliers.

What Each Fuel Is and How It Gets to Your House

Natural gas is mostly methane. The Department of Energy’s Alternative Fuels Data Center describes it as an odorless, gaseous mixture of hydrocarbons, predominantly methane, that accounts for about 30% of the energy used in the United States. Utilities add an odorant so leaks can be smelled. It arrives through an underground distribution main, a service line and a meter, and the utility is responsible for the system up to the meter.

Propane, also called liquefied petroleum gas (LPG), is a byproduct of natural gas processing and crude oil refining. The same DOE source explains that propane is stored under pressure in a tank as a colorless, odorless liquid, vaporizes into gas as pressure is released, and has an odorant, ethyl mercaptan, added for leak detection. Its main uses include home and water heating, cooking, clothes drying and farm equipment. A residential system typically includes an above-ground or buried tank, a first-stage regulator at the tank, a second-stage regulator near the house, and piping to the appliances. Our guide to the propane regulator explains how those stages work and what failure looks like.

Energy Content and Operating Cost

Comparing fuel bills is confusing because the two fuels are sold in different units. The fair way is to compare cost per unit of heat.

• Natural gas is typically billed in therms. One therm is defined as 100,000 Btu.
• Propane is billed by the gallon. The Alternative Fuels Data Center lists propane’s higher heating value at about 91,420 Btu per gallon, so roughly 1.09 gallons of propane deliver the same heat as one therm of natural gas.

Worked example (illustrative prices)

The numbers below are placeholders to show the method. Replace them with your own utility rate and propane quote, including delivery and fees.

1. Suppose your all-in natural gas rate, including delivery charges, works out to $1.20 per therm.
2. Suppose propane is quoted at $2.80 per gallon delivered.
3. Propane cost per therm-equivalent = $2.80 × (100,000 ÷ 91,420) ≈ $3.06.
4. In this example, propane costs roughly 2.5 times as much per unit of heat.
5. If a home uses 700 therms a year for heat and hot water, that is about $840 on natural gas versus about $2,140 on propane, before fixed fees.

Your ratio may be narrower or wider. Propane prices tend to move with the season, supplier and how much you buy at once, and many suppliers offer pre-buy or budget plans. Natural gas bills include fixed monthly service charges that matter more in low-use months. The efficiency of the appliance applies equally to both fuels: a 95% AFUE furnace converts the same share of fuel energy to heat whether it burns propane or natural gas, so the fuel price, not the appliance, drives the gap.

When comparing whole-home options, it is also worth pricing an electric heat pump. Our guide on heat pump vs furnace walks through when a cold-climate heat pump beats either gas fuel on operating cost, which happens more often against propane than against natural gas.

Upfront and Setup Costs

Natural gas hookup

If gas is already at the house, adding an appliance usually means a new branch line and a permit. If the house is not connected, the utility may charge for a service line and meter, and the cost depends on distance to the main, trenching conditions, and the utility’s line-extension policy. In some cases this is modest; in others, especially on large rural lots, it can be prohibitive. Ask the utility for a written estimate.

Propane tank: own or lease

Propane homes either lease a tank from the supplier or buy one outright. Common residential sizes range from small tanks for a single appliance to larger tanks for whole-house heating.

• Leasing typically means lower upfront cost, but you are tied to that supplier for fuel, and lease fees or minimum-use requirements may apply.
• Owning means a higher upfront cost, typically a few thousand dollars installed for a whole-house tank, but freedom to shop suppliers for each fill. You also take on responsibility for the tank’s condition.

Underground tanks cost more to install than above-ground ones and need corrosion protection. Either way, the tank must be placed according to the supplier’s and fire code’s clearance requirements from buildings, property lines and ignition sources. NFPA 58 is the national code most jurisdictions use for LP-gas storage; check with your city or county building department and your supplier for the requirements that apply to your lot.

Quote checklist

• Tank size, ownership or lease terms, and any minimum annual purchase
• Installation, pad, trenching and line to the house
• Regulators, gas piping, appliance connections and leak test
• Permit and inspection
• Delivery terms: automatic versus will-call, and any fees for small deliveries or after-hours service

Red flags include long lease terms with steep removal fees, no written price per gallon, and no mention of permits or a leak test.

Switching or Converting Appliances

Propane and natural gas are delivered at different pressures and need different orifice sizes, so appliances cannot simply be swapped from one fuel to the other. Many furnaces, water heaters, ranges and dryers can be converted with a manufacturer-approved conversion kit, which typically changes burner orifices and adjusts or replaces the gas valve or regulator. Some appliances cannot be converted at all.

A conversion should be done by a qualified gas technician who follows the manufacturer’s instructions, checks manifold pressure and verifies combustion afterward. A poorly converted appliance can burn with a lazy, sooting flame and produce carbon monoxide. If you buy a home that was converted from propane to natural gas, or the reverse, ask for documentation and have the appliances checked.

Safety: Leaks, Detectors and Carbon Monoxide

Both fuels are safe when systems are installed and maintained properly, and both are odorized so most people can smell a leak. The important difference is how each one moves. The Alternative Fuels Data Center’s fuel-properties comparison describes propane as a pressurized liquid that is heavier than air as a gas, and compressed natural gas as lighter than air. In practice:

• Natural gas tends to rise and disperse.
• Propane tends to sink and can collect in basements, crawlspaces and low areas, which makes a basement appliance leak more hazardous.

That difference affects where gas detectors belong. Detectors made for propane are generally mounted low, and natural gas detectors generally high, following the detector manufacturer’s instructions. Our roundup of the best gas leak detectors compares options for each fuel, and our guide to what a gas leak smell means covers the immediate steps: leave the building, avoid switches and flames, and call the supplier or utility from outside.

Carbon monoxide is a combustion problem shared by both fuels. The EPA lists back-drafting from furnaces and gas water heaters, gas stoves, unvented gas space heaters, and poorly adjusted or maintained combustion devices among indoor CO sources, and recommends having a trained professional inspect, clean and tune up central heating systems annually. The CPSC recommends battery-operated CO alarms or CO alarms with battery backup on every level of the home and outside sleeping areas, and notes interconnected alarms are best. Our roundup of the best carbon monoxide detectors covers models that meet those placement needs.

Front Range Factors: Altitude, Cold and Snow

Altitude derating

Gas appliances burn with less oxygen at Front Range elevations, so their input is reduced, or derated, at altitude. A commonly cited rule of thumb is a reduction of about 4% for each 1,000 feet above sea level beyond a threshold, but the method and threshold vary by manufacturer and appliance, and many modern units handle altitude through specific kits or settings. This applies equally to propane and natural gas. What matters is that the installer sets up the appliance for your elevation using the manufacturer’s high-altitude instructions. A furnace or water heater that is over-fired at altitude can run hot, short-cycle or produce excess carbon monoxide.

Cold weather and propane tanks

Propane vaporizes from the liquid in the tank, and that vaporization slows as the liquid gets colder. In a long cold snap, a small or nearly empty tank may struggle to supply a large heating load. Keeping tanks filled before winter and sizing the tank for the home’s peak demand reduces that risk. Many propane suppliers recommend not letting the tank drop too low in winter.

Snow, ice and access

Front Range snowstorms can bury tanks, regulators and gas meters. Keep a clear path for delivery trucks, and gently clear snow and ice from regulators and meters so their vents are not blocked. Ice on a regulator vent can affect pressure to the house. High-efficiency furnaces and water heaters also have sidewall intake and exhaust pipes that must stay clear of drifting snow.

Where each fuel is common

Natural gas serves most of the Denver, Colorado Springs, Boulder and Fort Collins metro areas. Propane is common in rural parts of Elbert, Douglas, El Paso and Jefferson counties, in foothills and mountain homes, and on larger eastern-plains lots where gas mains do not reach.

Appliance by Appliance: Where the Fuel Choice Shows Up

For most equipment, the burner design and installation matter more than which gas feeds it. Still, a few differences are worth knowing as you plan.

Furnaces and boilers

Space heating is usually the biggest fuel load in a Front Range home, so this is where the operating-cost gap is largest. On propane, a high-efficiency condensing furnace or boiler pays back faster than on natural gas because each therm-equivalent costs more. Sizing the tank for a long cold spell matters here too.

Water heaters

Tank and tankless gas water heaters are available for both fuels. Tankless units have high burner inputs, so on propane the tank, regulator and piping must be sized for that demand, and at altitude the unit must be set up for elevation. A heat pump water heater is another option worth pricing in propane homes.

Ranges and cooktops

Cooks rarely notice a difference between the two fuels once a range is configured correctly. Most ranges ship for natural gas and include or offer a propane conversion. Induction is the main alternative for off-main homes that want fast, responsive cooking without a tank.

Dryers, fireplaces and outdoor equipment

Gas dryers and fireplaces work on either fuel with the right configuration. Propane’s portability is the advantage outdoors: grills, patio heaters and fire tables often run on small cylinders even in natural gas homes. Standby generators can run on either fuel, but a generator on natural gas depends on the meter having enough capacity, and one on propane depends on enough stored fuel for a multi-day outage.

Whatever the appliance, keep the installation manual and any conversion or high-altitude kit paperwork with the house records. Future buyers, inspectors and service technicians will want to see them.

Which Should You Choose?

1. Gas main at or near the house: Natural gas, almost always, on operating cost and convenience.
2. No main, and an extension is costly: Propane for gas appliances, or compare against an electric heat pump and induction cooking.
3. Standby generator or outdoor kitchen on a natural gas home: Natural gas if the meter can supply the extra load; otherwise a dedicated propane tank.
4. Budget-sensitive propane household: Consider owning the tank so you can shop suppliers, and review pre-buy pricing.
5. Considering a switch in either direction: Confirm every appliance can be converted with a manufacturer kit, then price conversions, permits and any tank removal.

How a Home Inspector Evaluates Gas Systems

The ASHI Standard of Practice directs inspectors to inspect fuel storage and fuel distribution systems and to describe the location of main water and fuel shut-off valves, along with heating equipment and its energy source. A standard home inspection is visual. It typically covers:

• The fuel type and location of the main shutoff, whether at a gas meter or propane tank
• Visible gas piping, supports and connectors, including flexible appliance connectors and CSST bonding where visible
• Propane tank location, visible condition, regulator orientation and whether a leased tank has a supplier tag
• Furnace, boiler and water heater venting, signs of back-drafting, corrosion or scorching
• Presence and placement of smoke and CO alarms
• Evidence of improvised conversions or unpermitted appliance work

Inspectors do not typically pressure-test gas lines, measure tank contents or verify altitude derating settings. For those items, a licensed gas technician or the propane supplier is the right specialist. A dedicated furnace inspection goes deeper on heat exchangers, combustion and safety controls, and our heating and cooling hiring guide explains how to choose HVAC contractors and inspectors.

References

• Propane Fuel Basics — U.S. Department of Energy, Alternative Fuels Data Center
• Natural Gas Fuel Basics — U.S. Department of Energy, Alternative Fuels Data Center
• Fuel Properties Comparison — U.S. Department of Energy, Alternative Fuels Data Center
• Carbon Monoxide’s Impact on Indoor Air Quality — U.S. Environmental Protection Agency
• Carbon Monoxide Information Center — U.S. Consumer Product Safety Commission
• ASHI Standard of Practice for Home Inspection — American Society of Home Inspectors

Buying a Front Range home on propane, or one with an older gas furnace and water heater? Reach out through our contact page to connect with a local inspector before you close.