Deciding whether to install a boiler vs. furnace has a huge effect on your energy costs and personal comfort. Because each system operates in a fundamentally different way, homeowners should not only consider their heating needs, but upfront costs and long-term savings as well. In this blog, we’ll break down the key differences between furnaces and boilers, exploring their benefits and drawbacks to help you determine which one is the right choice for your home.
Boiler Systems
In the 19th and 20th centuries, boilers warmed buildings by pumping hot steam through radiators and baseboard heaters. Today, steam boilers are being overtaken by hydronic systems, which circulate hot water through copper or polyethylene pipes embedded under the floor. Hydronic systems are generally more efficient, easier to control, and safer to operate than steam systems, which has made them the leading choice in new construction.
Though there are a few boilers that still rely on heating oil, modern boilers are normally powered by natural gas or electricity. Homes in rural and some suburban communities, which have less access to gas pipelines, often power their units with compressed wood pellets instead.
No matter which type of fuel your boiler uses, it operates similarly to a water heater, except that rather than heating water for daily use, it uses it to warm your home. The process is simple. When the temperature dips, your thermostat signals the boiler, which ignites the burners, if you own a gas boiler, or activates the heating coil, if you own an electric one. The boiler heats the water inside the system to 160-180°F, then pumps it through your home.
Because radiant heat is absorbed directly by nearby surfaces, people and objects on the opposite side of a room with a panel, column, and baseboard radiator take longer to warm up. Radiant flooring systems, on the other hand, distribute warmth more evenly. Though hard to retrofit, they’re a popular choice for new homes. Regardless, after the water has completed its circuit through your piping, it returns to the boiler. If you own a steam boiler, the steam condenses back into water first. Then it’s reheated and sent out again, repeating the cycle until temperatures reach your desired level.
Furnace Systems
Furnaces generate heat and distribute warm air through a series of ducts. They’re categorized according to fuel source. Today’s furnaces are more efficient than they were 100 years ago, but they still operate along the same basic lines.
- Natural Gas Furnace. Like all furnaces, gas furnaces are controlled by your thermostat. When it detects a drop in temperature, it ignites the burners inside the combustion chamber. This raises the temperature of the heat exchanger. As air flows through, it heats up and is distributed through your house by the blower fan. Once it begins to cool, it’s drawn back into the furnace through a return vent, where it’s reheated and blown out again.
- Oil Furnace. Once an extremely common part of residential HVAC systems, oil furnaces are slowly being phased out in most parts of America. Natural gas is more affordable and produces few carbon emissions. Modern oil furnaces rely on kerosene, which is non-explosive and relatively clean. Besides burning kerosene, oil furnaces differ little from their gas counterparts.
- Electric Furnace. Instead of burners, these units run electricity through a metal coil with high electric resistance, which creates a buildup of electrons that generates heat. Electric furnaces are more expensive than gas or oil furnaces, but extremely efficient. Nearly 100 percent of the power they consume is turned into heat. By contrast, modern gas furnaces convert 98 percent of their fuel into heat, while oil furnaces only convert 80-90 percent.
Traditionally, furnaces operated at a single speed, meaning they could only run at full strength. Today, variable speed furnaces allow your HVAC system to generate heat at a lower setting in order to conserve energy when you only need to raise temperatures a few degrees.
Energy Efficiency
Because water holds heat better than air, it takes less fuel to run a boiler than a furnace. But even though boiler heating systems are more efficient, the amount of energy you’ll save depends on the type of fuel they require. Oil and gas boilers produce the biggest savings, while electric boilers produce the smallest.
Water retains heat well, but absorbs it at a relatively slow rate, which means that while boilers cost less to operate, it takes longer to feel their effects. Forced air systems circulate heat far more rapidly. Unfortunately, because they’re reliant on ductwork, their heat distribution isn’t as uniform. Hot air often winds up concentrated around vents and along the ceiling. Because radiant heat spreads evenly in all directions, its warmth is more consistent, especially when distributed through floor piping, which emits heat from every corner of the room.
Other Considerations
Though efficiency is the most important factor when deciding whether to purchase a boiler vs. a furnace, it’s not the only one. There are several other considerations, such as:
- Lifespan. With regular maintenance, boilers and furnaces typically last 15-20 years. Furnaces have air filters that need to be changed every 3-4 months, otherwise their service costs are nearly identical.
- Affordability. Furnaces have significantly lower purchase costs compared to boilers. In an effort to promote efficiency, the government’s ENERGY STAR Program offers tax rebates for boilers with Annual Fuel Utilization Efficiency (AFUE) ratings over 95 percent. Furnaces with ratings over 98 percent are also eligible.
- Air Quality. Because furnaces reduce humidity, running them all day can dry out your skin and irritate your nose, eyes, and throat. Boilers, on the other hand, don’t affect moisture levels. They don’t circulate dust, dander, or allergens either. One thing they have in common: gas boilers and furnaces both produce a number of dangerous fumes, including carbon monoxide. Though these byproducts are normally vented safely through exhaust ports, sometimes old units develop leaks. As a precaution, homeowners should always install carbon monoxide detectors throughout their home, to alert them of potential risks.
Finally, boiler installation is far more complex than furnace installation. Because they utilize the same duct system as your air conditioning, furnaces fit easily into existing infrastructure while new boilers need additional piping in the walls or under your floor, significantly increasing the amount of time, money, and effort in order to integrate them into your home.
Save On Heating Repairs with Agway
A reliable heating system requires reliable support. As components wear down, you need a maintenance team you can count on. Home insurance doesn’t cover problems stemming from daily use, but we do. Agway’s EnergyGuard™ Home Repair Program protects natural gas furnaces and boilers, as well as your internal wiring and central air conditioner from damage that accumulates over time.
When the need for repair occurs, our customers don’t have to waste time searching for a qualified technician. They call us instead. We maintain a network of HVAC contractors in your area and send the first available one straight to your door. There are no service fees or deductibles either. We pay for the visit and all covered parts. For your safety, comfort, and peace of mind, sign up and start enjoying the benefits of EnergyGuard™ today!
