What’s a Hydronic Pellet Boiler?

Pellet heaters are great. Real heat at the push of a button and none of the hassle you get from firewood and a wood heater. However, they are space heaters, which means they are good at heating a space like a lounge room. This doesn’t mean you can’t heat your whole home with a pellet heater but the heat won’t be evenly spread through your house. The room the pellet heater is in will be warmer than other rooms. Enter a hydronic pellet boiler. If you are looking for a way to heat your whole house evenly and have control over how much heat goes to rooms then a hydronic pellet boiler could be just the thing you need.

hydronic pellet boiler

Here’s the short version of what a hydronic pellet boiler is and does:

  • Central heating system that burns wood pellets to create hot water
  • Hot water is pumped around the house for heating
  • Heated water can also be used for domestic use (showering etc.)
  • Pellet boiler heat output ranges from 18kw to 50kw
  • Price ranges $6,000 to $10,000 for the hydronic pellet boiler
  • Approx $5,000 to $10,000 for plumbing and installation

What is a Hydronic Pellet Boiler?

A hydronic pellet boiler burns pellets to heat water. Boilers aren’t very popular in Australia but they work basically the same as boilers found in other countries that usually heat water with firewood or gas. As pellets in the pellet boiler are burn creating hot water, this hot water is then pumped around the house to provide heating. Heating is usually provided via underfloor pipes or radiators that are installed in rooms that require heating. The boiler usually has a storage tank, typically anywhere from 30 to 50 litres, which stores hot water as it is pumped around the house.

Some pellet boilers are installed with buffer tanks. These buffer tanks are basically hot water tanks, like a hot water heater most houses have, that store hot water. The advantage of doing this is the pellet boiler can heat water up which can then be used later for heating. Another advantage is this additional hot water can be used for domestic use, such as showering. Using buffer tanks means the pellet boiler won’t be running as often, as it will switch on, heat up the tanks and then switch off and only switch back on when the temperature of the water drops too low.

Hydronic Pellet Boiler vs Pellet Heater

Hydronic pellet boilers and pellet heaters are very similar in design and how they operate. The main difference is pellet boilers heat via hot water, whereas pellet heaters heat via hot air. Boilers have a hopper, an auger, a burn pot, exhaust fans, an igniter and pretty much almost everything you’d find in a standard pellet heater. However, because pellet boilers can go up to 50kw in heat output, compared to 13kw from a standard pellet heater, they are usually much larger. Hoppers often go up to 40kg and many models have hopper extensions or addons which expand the pellet storage.

Most pellet boilers are also installed outside of the house or area that is being heated. If used in a home you might find a pellet boiler under a house or possible in the garage or shed that might be attached to the house. The reason for this is because most boilers heat via hot water, there’s no need and it’s a waste of space to install them in a lounge room or in a room in your house. Also, as they need plumbing and other hardware to run pipes and hot water around, it’s often better to store them in an area that is out of the way.

What are Hydronic Pellet Heater Boilers?

Even though I just said pellet boilers are installed outside of the house, this isn’t always the case. There is a type of smaller hydronic pellet boiler that provides heat via hot air, like a standard pellet heater, and also via hot water. In Tassie you can buy Sampson pellet boilers in 18kw or 24kw sizes, but these boiler heaters are usually much smaller in heat output. About one third of the heat they provide, so about 6kw to 8kw, is used to heat hot air and the rest going to creating hot water. Because they blow out hot air, these boiler heaters are installed inside the house, maybe in a lounge room or somewhere that requires heating.

Due to their smaller heat output and size, pellet heater boilers are cheaper than dedicated boilers. They are a good option for anyone wanting to get a pellet boiler but a more affordable option. While the heat output is less, 18kw to 24kw is more than enough to heat most standard sized houses in Tasmania. Also, because the heater is installed in a lounge room this means you also get to see a fire and flame, which some people definitely enjoy seeing. This isn’t something you’d get with a pellet boiler as there is no winder to the burn box and the boiler is usually installed outside of the home.

Why Buy a Hydronic Pellet Boiler?

Now you know what a hydronic pellet boiler is, so why would anyone buy one? Pellet heaters are great. Real heat, real fast with very little hassle. However, they are space heaters. This means they are best at heating a space or fixed area or zone. You can heat a house with a pellet heater but you will find that some rooms in your house, like the room the pellet heater is installed in, will be warmer than other rooms, especially rooms that are further away from the pellet heater. Pellet heaters are not central heaters that provide an even amount of consistent heat throughout your whole home and nor do they allow you to control heat for each room.

Hydronic pellet boilers are whole house heaters. They will eventually distribute heat throughout your home to the rooms or areas that you want heated. You can usually also control the amount of heat that each room receives, such as turning the radiator in a bedroom up or down. Pellet boilers not only provide heating but can also provide hot water for your home. Hydronic pellet boilers are central heaters, whereas pellet heaters are space heaters that heat a specific area, such as a lounge room.

How Much do Hydronic Pellet Boilers Cost?

Pellet boilers are considerably more expensive than standard pellet heaters. You are going to pay anywhere from $10,000 to $20,000 for a pellet boiler. This includes the boiler unit, installation and heaters, such as radiators. The actual boilers cost anywhere from $6,000 to $10,000 and can be purchased from retailers such as Pellet Fires Tasmania if you live in Tasmania (Bass Pellet Heaters in Launceston also sell boilers) or check my where to buy a pellet heater post if you live outside of Tasmania. However, because they heat via hot water you will need pipes and plumbing installed.

You will then need heaters installed in the rooms you want to heat or underfloor pipes installed for floor heating. Finally, don’t forget that because pellet boilers heat a much larger area and can provide hot water, you will be burning more wood pellets than you would with a pellet heater. So, in comparison with a standard pellet heater, the boiler and installation will cost more and you will spend more on pellets. However, remember boilers are central heaters. You will be spending more but you will have a warmer home, it will be heated more evenly and you may even be getting hot water from the boiler also. This is all something a standard pellet heater can’t do.

What’s Better: Hydronic or Pellet Heater?

So which one should you buy or which one is best for you and your home? Choosing between a hydronic pellet boiler and a pellet heater depends on your heating needs and budget. First, do you want to heat a lounge room and warm the rest of your house or are you looking for a way to heat the whole house or many rooms and control how much heat these rooms get? Next, what are you willing to pay? A 12kw pellet heater is probably going to cost around $5,000 to $6,000 installed. A hydronic pellet boiler is going to cost anywhere from $10,000 to $20,000 depending on size of the heater and how many rooms you want heated.

Hydronic Pellet Boiler Summary

A hydronic pellet boiler is an excellent choice if you want to heat your entire home evenly and efficiently. While they may be more expensive than pellet heaters, they offer better control over temperature and can provide consistent heat throughout your home. When deciding between a hydronic pellet boiler and a pellet heater, consider the size of your home and your budget to make the best decision for your needs.

Wikipedia pellet boiler website