In this guide

Propane Boiler Costs by Material

The heat exchanger inside the boiler is made of one of three different materials - cast iron, aluminum, and stainless steel. Each has different attributes that make it a better fit for one situation over another, as well as different costs and life expectancies.

Cast Iron Propane Boiler

Most older boilers and some new standard boilers use a cast-iron heat exchanger. Cast iron is heavy and long lasting, as well as the least expensive material. It is not uncommon for a cast iron boiler to last 20 years or more. However, it is not as efficient at transferring heat as the other materials. It may not be used in high efficiency condensing boilers. Cast iron boilers cost between $1,200 and $3,000 on average.

Aluminum Propane Boiler

Aluminum is lighter than cast iron, allowing for wall-hung boilers. It also does a better job of transferring heat, so it has a higher energy efficiency rating at 94% on average. It is not usable in high efficiency condensing boilers and does not last as long as cast iron. Aluminum boilers cost between $2,500 and $4,000 on average.

Stainless Steel Propane Boiler

Stainless steel is a lightweight material that is excellent at transferring heat. It is used in high-efficiency condensing heat exchangers because it resists the corrosion that occurs from the high acidity in the condensed water better than cast iron or aluminum. This is the most expensive material, and while a stainless steel boiler lasts up to 15 years, the warranty is only good for 7 years in most cases due to the eventual corrosion that happens. Stainless steel boilers typically cost between $3,000 and $8,000 on average.

Hot Water vs Steam Propane Boilers

Boilers heat your home in one of two ways. They heat water, which is then distributed to either radiators or hydronic radiant heat systems. The water then circulates back to the boiler to be reheated.

Boilers also produce steam, which is sent to upright radiators where it condenses back to water and returns to the boiler for reheating. Steam boilers are larger and less efficient because they need to heat the water enough to produce steam. This type of heating system is less commonly used today for this reason, but many steam radiators still exist.

Because of their size and heating method, steam boilers have higher starting costs than water boilers despite being lower in efficiency. A steam boiler costs around $2,500 to $3,000, while hot water boilers start as low as $1,200 for standard-efficiency boilers.

Condensing vs Non-condensing Propane Boilers

Propane ¹ boilers come in two different types, known as standard and condensing. Standard boilers heat water and vent exhaust directly through a cast iron pipe. Some of the energy used to heat the water and your home is lost through the exhaust. A standard boiler achieves anywhere from 80% to 94% efficiency depending on the type of heat exchanger.

A condensing boiler takes the exhaust and condenses it to retrieve heat and energy before venting the remainder. By doing so, this boiler reaches efficiencies of 98%. However, this requires a stainless steel heat exchanger and a drain for the condensate, which is highly acidic. Condensing boilers save money on your energy bills each month, but are more expensive overall and do not last as long.

Combi Propane Boilers

If you have a small home and use propane to heat both your home and your hot water, you may want to invest in a combi or combination boiler. These small boilers heat the water for hydronic heating on one side and the hot water you use for bathing or laundry on the other. They are meant to be space saving as well as efficient, and typically use condensing heat exchangers. They are often small enough to be wall hung and are meant for use in smaller properties such as condos, tiny homes, apartments, and houses smaller than 1,000 sq.ft.

Combi boiler prices start at around $2,000 for very small units, with most having an average cost of about $3,000.

Sealed vs Non-sealed Combustion Propane Boilers

Boilers also come in both sealed and non sealed combustion forms. In a non-sealed combustion boiler, the unit needs to take inside air to aid combustion, meaning it is taking the heated air from your home and lowering the efficiency of the heater. It also means that dangerous gasses from the boiler may escape into your home.

Sealed combustion boilers take air from the outside, so they are more efficient than non sealed combustion boilers. They are also safer, as there is no chance for the gasses to escape into your home. Non-sealed combustion boilers tend to cost between $1,200 and $4,000, while sealed combustion ranges from $1,200 to $8,000 in costs.

Propane Boiler Costs by Brand

Many brands that make gas boilers also make LPG boilers or create boilers that use either gas or LPG with no conversion kits necessary. In addition, any gas boiler may be converted to an LPG boiler for an additional $25 to $100 kit, which means you have a lot of options for the brand and manufacturer of your propane ¹ boiler. Below are some of the more popular brands, which produce high-efficiency LPG boilers or gas and LPG boilers.

What Size Propane Boiler Do I Need?

Like other HVAC equipment, it is important to make sure you get the correct size boiler for your property. A boiler that is too small struggles to heat your home and a boiler that is too large wears out quickly and costs more in fuel.

To determine the best size boiler for your home, you need to know your climate zone and the amount of square feet that you heat. Find your climate zone by visiting the US Department of Energy’s climate zone map.

To get your square footage, multiply the length and width of each room in your home that you heat. Add up the results to get the total square footage of your home.

Propane boilers are sized by BTUs or British Thermal Units. Each climate zone has a recommended amount of BTUs per square foot that is necessary to comfortably heat a home. Locate your area on the map to discover your zone. Below find the number of BTUs per square foot for each area.

Multiply your square foot by the number of BTUs per square foot recommended for your area to get the general size of boiler you need. Keep in mind to stay within 10% to 20% of this range: any larger than this and the boiler is too large for your home. Below is the number of BTUs needed for several home sizes located in zone 4.

Labor Costs to Install a Propane Boiler

The cost to install a propane ¹ boiler varies depending on several items including the size and location of the boiler, whether it is sealed or unsealed, standard or condensing, and whether you have the drains, exhaust, and fuel lines in place or not. It costs between $1,000 and $3,000 in labor fees to install a propane boiler, with most people paying around $2,000 for a straightforward installation. If you need a new exhaust vent, drain, propane fuel line hookup, or other work, the price increases with additional costs from $500 to as high as $5,000.

Propane Boiler Replacement Cost

Many propane boiler installations are replacements, meaning you already had a propane boiler and are replacing it with a newer model, rather than setting up a propane boiler for the first time. In most cases, the boiler you are installing for the replacement is newer, more energy-efficient, and requires things in its setup that older boilers did not, such as exhaust vents, drains, and new fuel lines. For this reason, the average cost to replace a propane boiler is about the same as it is to install a new one - $7,500 for a boiler designed for hydronic heating.

Cost to Run a Propane Boiler

Propane is more expensive than natural gas but is usually less expensive than either oil or electricity. There are several factors that go into determining running costs for your propane boiler, including the cost of propane in your area, size of boiler, and its efficiency rating.

Liquid propane is sold by the gallon, with the national average cost per gallon of propane at the end of March 2020 being $1.869. One gallon of propane produces 91,547 BTUs. To determine how much it costs to run your propane boiler for one hour, you need the number of BTUs your boiler produces and the cost of propane in your area.

Divide the number of BTUs your boiler produces by 91,547 to get the number of gallons of propane you use in one hour. A boiler that produces 200,000BTUs uses 2.18 gallons of propane an hour. At a rate of $1.869, this boiler costs roughly $4.07 an hour to run.

High-efficiency Propane Boiler Prices

Propane ¹ boilers come in a range of efficiencies, with the most efficient coming in at 98%. These boilers use stainless steel heat exchangers and are condensing units that help recover some of the heat from the exhaust so they use less fuel. The cost of these boilers is between $3,000 and $8,000 on average, depending on the size and model.

Oil vs Propane Boiler

If you live in an area of the country where natural gas is unavailable, you have a choice of either oil or propane for heating your home. Both are delivered to your home and stored on your property in tanks. Of the two, propane tends to be less expensive to purchase, although oil burns hotter, so you use less of it each day.

Oil boilers tend to be higher in maintenance than propane boilers because the soot produced by the oil often clogs the lines and needs to be cleaned out regularly. Propane burns cleaner, with fewer particulates, which means that it is better for the environment and less likely to clog your lines.

An oil boiler of the same size costs around $6,500 installed, but only reaches roughly 91% efficiency, so while it may be less expensive to install, it costs more in fuel monthly.

Electric Boiler vs Propane Boiler

Another choice for homes that do not have access to natural gas is an electric boiler. Electric boilers use electricity to heat the water. Due to the high cost of electricity, though, they are often smaller and used primarily in zones 1 & 2 where not much heat is needed. They are a good choice for home additions, where the addition needs a different heating system than the rest of the house.

If you live in a moderate or cold climate, however, and you want to use a boiler to heat your whole house, propane is the better choice. Propane boilers are larger, hold more water and produce more heat, and cost less to run.

Propane Boiler Service Cost

Propane ¹ boilers are relatively low maintenance, only requiring service once every few years. This service costs between $50 and $200 on average, depending on whether or not any parts need to be replaced to help keep your boiler running efficiently.

The only maintenance that you may need to perform regularly is occasionally flushing the system to remove any sediment from inside the line, and refilling with fresh water.

Manual J Calculation

To truly determine what the best size boiler is for your home, your HVAC technician performs a Manual J calculation. This formula takes into account the square footage of your home, your climate zone, and how much insulation your home has, as well as any other energy-saving features. This gives you the most accurately sized boiler for your home, so trust that you are not overpaying in energy bills.

Enhancemet and Improvement Costs

Old Boiler Removal

Most HVAC companies remove your old boiler at no additional cost. However, some may charge a fee between $50 and $200 for removal and disposal, depending on its age and location.

Boiler Insulation

Adding insulation to your boiler reduces energy costs by slowing the amount of heat lost by the boiler. Insulation costs between $50 and $100 on average.

Wall-mounted Propane Boiler

If you have a lighter aluminum or stainless steel boiler, it is likely wall mounted ² to help save space. Many boilers today are available as a wall-mounted unit. They have costs starting at $2,500 on average.

Programmable Thermostat

Another way to get a good handle on your energy costs is to install a programmable thermostat, which allows you to automatically reduce your boiler usage during the times when you are not at home. A programmable thermostat costs between $145 and $230 installed.

Generator

If the power goes out, your boiler’s motor stops working. For this reason, you may want to invest in a portable generator to keep your boiler working. They have starting costs of around $2,000.

Remodeling Terms Cheat Sheet

¹ Propane: A hydrocarbon gas used as a common fuel source

³ Thermostat: A device that senses and regulates temperature by turning heating and cooling devices on and off