If you want to replace your boiler, there has never been a better time to upgrade to a more energy-efficient model. Modern boiler models are more dependable and eco-friendly than ever. While you’ll have to pay more for a higher-efficiency boiler, it will also work better and reduce the amount you have to pay for your radiant heating. In this article, we’ll explore the various types of boilers and how they compare in terms of energy efficiency and heating costs.
Heat Pump Boilers
Electric heat pump boilers are the newest and most advanced type of boiler. The most common type is an air-to-water boiler, which is similar to a standard heat pump, except it serves a radiant heating system instead of a central forced-air heating system. It works via a heat pump unit that captures heat from the air using a special coil and refrigerant.
After the refrigerant moves through the coil and captures heat, it then gets compressed and becomes extremely hot. The heat pump then pumps the refrigerant to the boiler’s heating tank inside. As the refrigerant flows through this tank, all of the heat gets released into the water so that it eventually gets fully hot. There are also ground-source heat pump boilers, which work similarly, except that they capture heat from underground instead of pulling it out of the air.
Air-source heat pump boilers can be anywhere from 200-400% efficient, meaning they use much less energy than the heat they produce. However, their energy efficiency decreases when the air temperature outside is below 40 degrees. This is why some are hybrid boilers with electric resistance heating elements that allow them to work more effectively in cold weather.
It also ensures the boiler can still heat if it’s too cold outside for the heat pump to work. While the popularity of heat pump boilers will definitely increase at some point, the high cost is prohibitive for many property owners. A heat pump boiler could easily cost five times as much as a traditional boiler. The other drawback is that they heat more slowly since they can’t get the water as hot as gas and traditional electric boilers do.
Combi-Boilers
Combi-boilers are combination uses that provide hot water for both radiant heating and plumbing. Most of these units run on natural gas or propane, but electric units are also available. Either option provides on-demand hot water for the plumbing system and will also run whenever the thermostat for the radiant heating system calls for heat. However, the unit always prioritizes the plumbing system, meaning it can’t provide hot water to your radiant heating system when you shower, wash your hands, run the washing machine on warm or hot, etc.
Electric combi-boilers are technically around 98-100% efficient, whereas gas combi-boilers are typically between 90% and 95% efficient. Nonetheless, gas units cost less to use. That’s because electricity costs more than gas, and electric units have much higher energy demands.
A combi-boiler is often the best choice if you have a smaller property or your hot water demands for plumbing aren’t all that high. If you have a large house or low water pressure, the unit will struggle at times to provide sufficient hot water for your plumbing. With a combi-boiler, you also have to be more careful about when you use hot water during the winter. That’s because the boiler will continually stop supplying hot water to your heating system any time you need hot water for your plumbing. In some cases, this can result in the temperature in your property dropping and the boiler then struggling to bring it back up.
Traditional Gas Boilers
Traditional gas boilers are either conventional or condensing units. Conventional units range between 80% and 88% efficient. Most condensing boilers range from 90% to 95% efficient, but some of the top-of-the-line units are around 98-99% efficient. Condensing boilers are more efficient because they capture and transfer more of the heat their burners produce, so less energy gets wasted. That means outside of a heat pump boiler, a condensing boiler is going to be the most energy-efficient option.
This type of boiler has a cold water reservoir and a hot water reservoir. When the thermostat calls for heat, the burner immediately lights and starts supplying heat to the water within the hot water tank. Once the water reaches the correct temperature, the boiler’s pump starts circulating the hot water to the underfloor heating tubes or radiators. The water loses some heat as it moves through the system before finally flowing back to the cold water tank.
Some gas boilers work by producing steam instead of just hot water. Steam boilers are much less common than they used to be since they’re not as efficient as hot water condensing boilers. While the technology has improved, you can still typically only achieve around 88% efficiency with a steam boiler. Steam boilers are also more expensive to run since they take more heat and, thus, more energy to get the water hot enough to boil. Nonetheless, a steam boiler is your only option if you have an older radiant heating system with steam radiators.
Electric Boilers
As with electric combi-boilers, electric conventional boilers are nearly 100% efficient, meaning little to no energy gets wasted. However, using an electric conventional boiler will generally result in higher heating costs than with any other type of boiler due to how much energy an electric boiler uses.
On the plus side, electric boilers are the least expensive type of boiler and usually last longer than traditional gas boilers. The other benefit of an electric boiler is that it doesn’t require an exhaust vent since it doesn’t produce emissions like gas boilers. That means you also never need to worry about the boiler causing any potential carbon monoxide issues in your house, which is a possibility if you have a gas boiler.
Need Help Finding an Energy-Efficient Boiler?
Bobby L. Greene Plumbing, Heating & Cooling Co. is a locally-owned company that’s been serving Shreveport, LA, and the surrounding parishes for over 60 years. As the area’s top boiler service, we can assist you with choosing and installing a new unit. We offer expert residential heating and air conditioning services as well as top-notch plumbing services for both residential and commercial customers.
When you turn to us for your HVAC and plumbing needs, you can trust we’ll handle everything promptly, reliably, and at an honest price. If you’re not sure which type of boiler is best for your property, give us a call. We’ll advise and assist however we can.
