Nerding out about heaters
The weather in Cape Town is slowly descending into a cold, wet winter (except for today, which is a beautiful). I've brought the heater up from the garage, doubled up the duvets on the bed, and have started wearing long pyjamas to sleep.
Generally at this time of year Emma and I are making plans to head somewhere warm, but this year we've decided to stick it out in South Africa with a month-long road-trip to the North West for some proper time in the bushveld, and then a wedding in Joburg.
For people not from South Africa, it does get cold here. Not in the same way it gets cold in Canada or Northern Europe, but in some ways it gets colder. Let me explain:
In Canada the Canadians know that it's going to get very, very cold. Unbelievably cold. Because of this they do a whole bunch of reasonable things like insulate their homes, ensure they have a robust heating system, and purchase proper winter attire. But not in South Africa. Our weather is great most of the year, with only about 2 to 3 months of cold weather.
It can get down to 5 degrees Celcius on a cold day; and while that may not seem cold to people where the weather gets to -20, we're always completely unprepared for it. Because of our good weather the rest of the year, we forget. We forget to insulate our houses. We forget to get winter sheets. And so when the time comes even the insides of our homes are cold.
I've had Polish and German friends suffer in the South African winter due to a lack of good heating and insulation. And that brings me to my topic of interest today: Heaters.
There are so many different kinds of heaters on the market. Everything from wood fireplaces to under-floor hot water heating. Now, unless you're lucky and your house or apartment has built in heating or a fireplace of some sort, you're stuck purchasing a heater from a store (or layering up, or both).
At the end of the day there are only have 3 different kinds of heating (for the purposes of this write-up):
Conduction - where you physically touch the heated surface and that heat is transferred to you via the conductivity of the surface and the body in contact.
Radiation - where infrared light is radiated from a heating element and absorbed by our skin (or the surrounding objects) over a distance.
Convection - where the heated surface warms the surrounding air, which in turn warms us. While convection involves conduction at a molecular level (heat transfer between particles), it’s distinct from conduction because it relies on the movement of a fluid (air in this case).
Most heaters rely on a combination of these mechanisms. Wood fireplaces predominately rely on radiation (infrared from the fire) and convection (warming up the surrounding air). Under-floor heating relies on conduction (direct contact with the floor) and some convection, although this isn't the main mechanism. Electric quartz heaters (those pretty glowing bars) are predominately radiation, and the oil-filled space heaters are predominately convection.
Store bought heaters come in a variety of shapes, sizes, and price points. But I noticed that by-and-large they all have the same max wattage of 2000 watts (I believe in the US it's 1500 watts due to their 120 volt power supply). Now, theoretically energy is energy is energy. Therefore, if you have a sealed room each one of these heaters will emit the same amount of heat into the room at the same rate, regardless of whether this is an expensive heater or one of those cheapie blower types you put under your desk. And since every 2000 watt heater will cause the same amount of heating and draw the same amount of power, then the mechanism of action shouldn't be that important. Or is it?
We have 3 heaters in our apartment. A quartz bar heater, a fin space heater, and an electric blanket. And they each have their own strengths and weaknesses.
The quartz bar heater is by far my favourite. As soon as I turn it on it starts radiating a gentle warmth directly onto me. This is lovely since I don't sleep with the heater on, so when the apartment is cold in the morning I can sit in front of it with my coffee and be all toasty without having to warm up the entire space. It also warms up the couch I'm sitting on, which provides conductive heating as well. Warming up the entire space is also not easily (or cheaply) done due to South African building's lack of insulation.
Left on for long enough and it does gradually increase the temperature of the room, since that same number of wattage is being radiated into the space where it's absorbed by the floor and furniture, heating them up. Those objects inevitably heat up the air around them, and boom! You have convection.
The fin space heater is no-where near as nice. Due to it relying on convection to heat up the entire space it isn't very efficient (again, no insulation). Instead we use this exclusively in the home office which is a smaller space, has slightly better insulation, and a carpet which I wouldn't like to rest the bar heater on due to the localised heat.
It is a great example of how doing something useful with the heat first is important. With the bar heater it warms me and the objects I interact with up before trying to warm up the surrounding air. Again, in the end it's 2000 watts regardless of method, so may as well make use of that energy locally before trying to warm up the room.
My third heater is the electric blanket. If I put this on 10 minutes before getting into bed it warms it up so well that it's such a toasty pleasure to get into. This is also by far the most efficient form of heating since it is insulated by default, and relies entirely on conduction. It warms up the specific area that I will inhabit without losing much heat to the surrounding area. Due to this the power draw of an electric blanket is negligible compared to actual space heaters (about 7-10%). This is a great example of super localised heat. There's no way that I'm going to use my electric blanket to heat up the apartment.
I grew up with gas heaters (and briefly an anthracite stove heater) and have spent a decent amount of time with wood-fired stoves and fireplaces, and I can honestly say that electricity is just so much subjectively better. No having to leave the window open to vent the carbon dioxide (meaning more gas needs to be burnt to compensate). No ash coating surfaces around the fireplace, no smell of smoke in the house. No having to constantly replenish stocks of wood or haul around gas canisters.
Also, being able to flick the bar heater on and off as needed is great when compared to starting and maintaining a fire in a wood-burning stove. I only spend 45 minutes having coffee before heading to gym in the morning and really couldn't be bothered to make a fire. I'm also a fan of consistent heat instead of the fluctuations of burning hydrocarbons. But that's personal preference and relegated to indoors. I love a good campfire and the ambiance of fire in general.
There are many other heater designs, but when narrowed down to wattage and mechanism, it helps me reason about it better. I guess what can be taken away from this writeup is that if you're stuck deciding between heaters, just know that they'll probably all heat up your space at the same rate, but finding a way to use that heat locally first is good practise. Also, save your money. Expensive heaters are not better by default.