Types of Heaters and their pros and cons
Choosing the right heater is a minefield for many of us: so many different options and prices. We can go for a cheap fan heater for little more than $15 to hundreds of dollars for more advanced heaters. And so, when you stand in front of a shelve full of different heater options, you, like me, struggle. So we did some research, drew on experience and knowledge of specialists and compared it to our past, as we lived in houses that had those different type of heaters.
Before choosing any heater, you should ensure that whatever you choose, the device can heat the space you want to be heated. To calculate the size heater you need click here. Secondly, you should ensure that you select the right heating device for what you require. And thirdly, choose a heater that is economical to run, saving you much money in the years of operation. To make things easier, we will share here our research in all three heating categories: radiant heaters, air heaters and infrared heaters. We will explore how they work, their benefits and shortcomings.
Imagine you are sitting in front of a fire. The high temperature of the fire emits waves directly to you, without heating the air. Those waves will keep you warm. And those waves are called radiant heat. However, the majority of heat of a fire is actually given out via heating air. As air brushes past the fire, it heats up and rises, allowing more air to heat. Radiant heaters heat up bodies, that reflect heat back into the surrounding air. This is a more comfortable and natural way to heat (same as the sun), that is comfortable at a slightly lower air temperature than air heaters (between 1-2 degrees Celsius).
According to the master plumbing organisation in NZ, underfloor radiant heating devices that we will cover soon, warm bodies with radiant heat to about 60% and heat the air with about 40% of the energy (1). All radiant heaters tend to be more efficient than air heaters because of the way the heat is distributed.
Underfloor heating is one of the types of available radiant heat. Underfloor heating is considered to be one of the most comfortable ways to heat your home or building. Reason for this comfort is threefold:
Underfloor heating works on a low temperature coming through the floor, creating thereby only minimal airflow
Underfloor heating creates very few hot of cold spots in homes, as the heat is evenly distributed
Underfloor heating has the warmest air temperature on the floor. As the warm air rises off the floor, it mixes with its surrounding air and cools slightly down, creating comfort
In New Zealand, there are different versions used in underfloor heating.
Many people choose to install the pipes for heating in the actual concrete slab. Fitting in the slab has the advantage of adding thermal mass, a storage battery for when you need it. This means that if you have a warm floor and for a couple of days no fuel to power your heating, you stay warm most of the time.
The disadvantage of installing in the slab is the speed of heat. It will take a few days for the floor slab to be heated up properly to heat your home. Another advantage or disadvantage is that it is difficult to regulate the heat: even if you turn off a valve in one room, some of the heat from the neighboring pipes will go to colder places in the concrete slab and thereby lost. Also, it is vitally important that if you do use a floor slab underfloor heating system, to use a fully insulated floor slab. In NZ, there is as of the beginning of 2020 no regulation for the sides to be insulated.
Another version is to install them on top of the concrete slab and pouring a so-called screed on top of the pipes. The screed acts as a smaller thermal mass, storing less heat that the floor slab. The advantage of this method is that here you can heat different rooms as you please without heat loss. The time it takes to heat a room is also faster. However, as said, you will not be able to store as much heat as by installing the pipes into the slab.
A third option is electric underfloor heating. Here, wires are installed underneath tiles. Whenever you turn on the heating system, the wires heat the tiles to give you warm feet. Electric underfloor heating is usually used in bathrooms. The advantage of those is that the heat is going through very fast and with minimal heat loss. The disadvantage is that it is expensive to create heat purely with electricity. Using a heat pump, gas, diesel or wood are cheaper forms of heating in most areas.
How do radiant heaters work?
Wall-mounted radiators are hot surfaces that are installed on the wall or ceiling. Wall-mounted radiator heat is best known for its ability in delivering warmth into your room at speed. Examples are not just heater devices mounted on the wall, but also fireplaces or pellet burners. Wall-mounted radiators have the following advantages:
Wall-mounted radiators are much cheaper to run than fan or panel heaters
Radiators heat spaces faster than underfloor heating
Though wall-mounted radiators only use other materials as thermal battery storage to a small degree, the advantage of this is that only a little heat is lost for when it is not needed
The disadvantage of this type of system is that you have to create heat when you need it. And that time is often during peak hours, causing higher energy costs. Wall heaters should not have furniture placed in front of them. That means you are losing wall space if you need it. To heat your room the radiators have temperatures around 55 degrees Celsius, creating hot and cold spots in your room; the same as with a fan or bar heater.
Most types of radiate heating are in the form of wood fires or hydronic (water) heating. In NZ, wood fires are used to heat just one room. Hydronic heating is mostly used for a central heating system to heat your entire house. Radiant heating has the advantage compared to air heating that it keeps the warmth for longer after it is turned off.
Infrared heaters are also radiant heaters, but because of their efficiency, they do deserve their own category.
Infrared heaters work by emitting infrared light energy, which is invisible to humans. This light comes in the form of waves and carries heat.
The infrared light waves do work the same as sunlight, which also heats us with infrared light, which is according to science good for our health (2). Infrared panels are most effective if installed on the ceiling or wall. Infrared light waves penetrate the skin deeper than other forms of heating, which has been shown in several medical research studies.
Near-Infrared heaters have a shorter wavelength than far-infrared. Near-infrared do emit heat that you likely feel on your skin. Feeling the temperature on your body makes them ideally suited for outdoor areas or rooms where you only spent a small amount of time in, but want heat instantly. Many outdoor heaters are near-infrared heaters.
Far Infrared Heaters
Far Infrared Heating is used actively in saunas by sports teams and recommended by health professionals because of its health benefits.
Far infrared rays come at a different wavelength compared to near-infrared. The advantage of far infrared heaters is that because they only heat to a very minimal part the air, the vast majority of heat is delivered to bodies and objects, which reflect the heat into the atmosphere. This does make them the most efficient radiators at present.
We did buy a few far infrared heaters many years ago, and without any maintenance, a 600W heater heats our 12sqm uninsulated bedroom with large windows without trouble. According to the official government calculator, we would need a 1.58kW heater for this room if we were to use an air heater.
Far infrared heaters will heat space very fast, and although the air is colder than with other forms of heating, it feels comfortable.
Air heaters heat the air around them and then either let the air naturally rise or force the air around the room.
Air heaters are usually the cheapest type of heaters, however also the most inefficient, therefore requiring the most energy. For the heat to get from the heating device to you, it needs to heat the air in between. The large volume of air in the room also means that you usually require a larger air heater than a radiator. Air heaters do get cold very fast after they are turned off. Further, as the building loses air, it loses heat, which means an air heater has to work more.
A convection heater works by heating a usually metal surface. Air surrounding the metal part will heat up and rise. The heated air will mix with colder air and slowly heat the room. An advantage of convection heaters is that if furniture is placed in front of them, only minimal heat is lost. All that is required is that cold and warm air can flow to and from the convector.
A disadvantage of convector heaters is that they stop working very quickly after it is turned off. Further, a higher air temperature is required to achieve the same comfort level than radiant heaters.
Forced Air Heaters
Forced air heaters distribute heated air via a fan. They are a bit faster in heating a space than a convection heater. However, like a fan heater, they do because of the fan also use more power to run them.
Heat pumps are more efficient forced air heaters because they take the heat out of the air and compress it, creating more heat out of less energy.
(1) Master Plumbers, Radiators and underfloor (hydronic) heating, 11.07.2019
(2) International Medicine, Leg Heating Using Far Infra-red Radiation in Patients with Chronic Heart Failure Acutely Improves the Hemodynamics, Vascular Endothelial Function, and Oxidative Stress,Shujiro Inoue1, Masao Takemoto1, Akiko Chishaki2, Tomomi Ide1, Mari Nishizaka1, Mami Miyazono2, Hiroyuki Sawatari2 and Kenji Sunagawa, 2012